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1
Nandekar, Kamlakar. "Novel Applications of Some Organic Copolymers Derived From Phenolic and Nitrogen-Containing Compounds- A Review". Journal of ISAS 2, nr 1 (31.07.2023): 15–26. http://dx.doi.org/10.59143/isas.jisas.2.1.kdqi5413.
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A variety of organic copolymers have been synthesized from phenolic compounds like p-Hydroxybenzoic acid, p-Hydroxybenzaldehyde, p-Hydroxyacetophenone, and also from nitrogen- containing compound like anthranilic acid, aniline, urea, biurate. These copolymers have been studied for various properties like thermal behavior, kinetic parameters, antimicrobial screening, ion-exchange study, polymer composites, photoluminiscence etc. Kinetic parameters of the copolymers derived from phenolic and nitrogen-containing compounds have been studied using Freeman-Carroll (FC) and Sharp-Wentworth (SW). Based on TGA, thermal stability and decomposition temperature have been studied for the copolymers and composites. Higher thermal stability for copolymer composites has been found as compared to the copolymer because the composite has a high activation energy and more residue left out at the end of the decomposition process. The metal ion uptake capacity of the copolymer have been studied by using the batch equilibrium method and is useful for wastewater treatment. The antimicrobial activity of the copolymers have been studied using the agar diffusion method. Polymer composites have been made from copolymers using an ultra-sonication process and exhibit excellent properties in metal ion uptake for wastewater treatment. The present review paper involves the study of novel applications of the copolymer resins derived from phenolic compound and nitrogen-containing compound.
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Chon, Yang, Lee, Kim, Jeon, Jho i Chung. "Novel PEEK Copolymer Synthesis and Biosafety – I: Cytotoxicity Evaluation for Clinical Application". Polymers 11, nr 11 (2.11.2019): 1803. http://dx.doi.org/10.3390/polym11111803.
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In this research, we synthesized novel polyetheretherketone (PEEK) copolymers and evaluated the biosafety and cytotoxicity of their composites for spinal cage applications in the orthopedic field. The PEEK copolymers and their composites were prepared through a solution polymerization method using diphenyl sulfone as a polymerization solvent. The composite of PEEK copolymer showed good mechanical properties similar to that of natural bone, and also showed good thermal characteristics for the processing of clinical use as spine cage. The results of an in vitro cytotoxicity test did not show any evidence of a toxic effect on the novel PEEK composite. On the basis of these cytotoxicity test results, the PEEK composite also proved its in vitro biosafety for application to an implantable spine cage.
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BARIM, Esra. "Synthesis, Characterization, Optical and Thermal Properties of P(NVC-co-BZMA) Copolymer and Its ZnO Composites". Gazi University Journal of Science Part A: Engineering and Innovation 9, nr 4 (31.12.2022): 526–36. http://dx.doi.org/10.54287/gujsa.1199767.
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Recent studies have paid particular attention to polymer-nanoparticle composite materials considering they have a number of interesting properties, which include optical, thermal, electrical, and others (Reyna-Gonzalez et al., 2009; Yakuphanoglu et al., 2010). In this study, a free radical polymerization process was used to create a copolymer of N-vinylcarbazole (NVC) and benzyl methacrylate (BZMA) at 25–75 mol% each. The procedure was conducted at 70°C with azobisisobutyronitrile (AIBN) acting as the initiator. Nano zinc oxide powders were then added to composites at three different ratios of 5%, 10%, and 15% weight of the copolymer. In order to better understand the structures of the P(NVC-co-BZMA) and its composites, FT-IR, 1H NMR, and UV spectroscopic techniques were also implemented. The optical characteristics of both the pure copolymer and its composites were examined. In the visible region, the composite containing 15% nano ZnO had the highest optical absorbance value. Additionally, the thermal behaviours of the composites and copolymers were analysed.
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Tzoumani, Ioanna, Zacharoula Iatridi, Athena M. Fidelli, Poppy Krassa, Joannis K. Kallitsis i Georgios Bokias. "Room-Temperature Self-Healable Blends of Waterborne Polyurethanes with 2-Hydroxyethyl Methacrylate-Based Polymers". International Journal of Molecular Sciences 24, nr 3 (29.01.2023): 2575. http://dx.doi.org/10.3390/ijms24032575.
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The design of self-healing agents is a topic of important scientific interest for the development of high-performance materials for coating applications. Herein, two series of copolymers of 2-hydroxyethyl methacrylate (HEMA) with either the hydrophilic N,N-dimethylacrylamide (DMAM) or the epoxy group-bearing hydrophobic glycidyl methacrylate were synthesized and studied as potential self-healing agents of waterborne polyurethanes (WPU). The molar percentage of DMAM or GMA units in the P(HEMA-co-DMAMy) and P(HEMA-co-GMAy) copolymers varies from 0% up to 80%. WPU/polymer composites with a 10% w/w or 20% w/w copolymer content were prepared with the facile method of solution mixing. Thanks to the presence of P(HEMA-co-DMAMy) copolymers, WPU/P(HEMA-co-DMAMy) composite films exhibited surface hydrophilicity (water contact angle studies), and tendency for water uptake (water sorption kinetics studies). In contrast, the surfaces of the WPU/P(HEMA-co-GMAy) composites were less hydrophilic compared with the WPU/P(HEMA-co-DMAMy) ones. The room-temperature, water-mediated self-healing ability of these composites was investigated through addition of water drops on the damaged area. Both copolymer series exhibited healing abilities, with the hydrophilic P(HEMA-co-DMAMy) copolymers being more promising. This green healing procedure, in combination with the simple film fabrication process and simple healing triggering, makes these materials attractive for practical applications.
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Prasomsin, Wassika, Tewarak Parnklang, Chaweewan Sapcharoenkun, Sunan Tiptipakorn i Sarawut Rimdusit. "Multiwalled Carbon Nanotube Reinforced Bio-Based Benzoxazine/Epoxy Composites with NIR-Laser Stimulated Shape Memory Effects". Nanomaterials 9, nr 6 (14.06.2019): 881. http://dx.doi.org/10.3390/nano9060881.
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Smart materials with light-actuated shape memory effects are developed from renewable resources in this work. Bio-based benzoxazine resin is prepared from vanillin, furfurylamine, and paraformaldehyde by utilizing the Mannich-like condensation. Vanillin-furfurylamine-containing benzoxazine resin (V-fa) is subsequently copolymerized with epoxidized castor oil (ECO). When the copolymer is reinforced with multiwalled carbon nanotubes (MWCNTs), the resulting composite exhibits shape memory effects. Molecular characteristics of V-fa resin, ECO, and V-fa/ECO copolymers are obtained from Fourier transform infrared (FT-IR) spectroscopy. Curing behavior of V-fa/ECO copolymers is investigated by differential scanning calorimetry. Dynamic mechanical properties of MWCNT reinforced V-fa/ECO composites are determined by dynamic mechanical analysis. Morphological details and distribution of MWCNTs within the copolymer matrix are characterized by transmission electron microscopy. Shape memory performances of MWCNT reinforced V-fa/ECO composites are studied by shape memory tests performed with a universal testing machine. After a significant deformation to a temporary shape, the composites can be recovered to the original shape by near-infrared (NIR) laser actuation. The shape recovery process can be stimulated at a specific site of the composite simply by focusing NIR laser to that site. The shape recovery time of the composites under NIR actuation is four times faster than the shape recovery process under conventional thermal activation. Furthermore, the composites possess good shape fixity and good shape recovery under NIR actuation.
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Tzoumani, Ioanna, Amaia Soto Beobide, Zacharoula Iatridi, George A. Voyiatzis, Georgios Bokias i Joannis K. Kallitsis. "Glycidyl Methacrylate-Based Copolymers as Healing Agents of Waterborne Polyurethanes". International Journal of Molecular Sciences 23, nr 15 (23.07.2022): 8118. http://dx.doi.org/10.3390/ijms23158118.
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Self-healing materials and self-healing mechanisms are two topics that have attracted huge scientific interest in recent decades. Macromolecular chemistry can provide appropriately tailored functional polymers with desired healing properties. Herein, we report the incorporation of glycidyl methacrylate-based (GMA) copolymers in waterborne polyurethanes (WPUs) and the study of their potential healing ability. Two types of copolymers were synthesized, namely the hydrophobic P(BA-co-GMAy) copolymers of GMA with n-butyl acrylate (BA) and the amphiphilic copolymers P(PEGMA-co-GMAy) of GMA with a poly(ethylene glycol) methyl ether methacrylate (PEGMA) macromonomer. We demonstrate that the blending of these types of copolymers with two WPUs leads to homogenous composites. While the addition of P(BA-co-GMAy) in the WPUs leads to amorphous materials, the addition of P(PEGMA-co-GMAy) copolymers leads to hybrid composite systems varying from amorphous to semi-crystalline, depending on copolymer or blend composition. The healing efficiency of these copolymers was explored upon application of two external triggers (addition of water or heating). Promising healing results were exhibited by the final composites when water was used as a healing trigger.
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O'Donnell, Justin N. R., i Drago Skrtic. "Degree of Vinyl Conversion, Polymerization Shrinkage and Stress Development in Experimental Endodontic Composite". Journal of Biomimetics, Biomaterials and Tissue Engineering 4 (grudzień 2009): 1–12. http://dx.doi.org/10.4028/www.scientific.net/jbbte.4.1.
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This study explores degree of vinyl conversion (DVC), polymerization shrinkage (PS) and shrinkage stress (PSS) of the experimental amorphous calcium phosphate (ACP) composites intended for use as an endodontic sealer. Light-cure (LC), chemical cure (CC) or dual-cure (DC; combined light and chemical cure) resins comprised urethane dimethacrylate (UDMA), 2-hydroxyethyl methacrylate (HEMA), methacryloyloxyethyl phthalate (MEP) and a high molecular mass oligomeric co-monomer, poly(ethyleneglycol)-extended UDMA (PEG-U) (designated UPHM resin). To fabricate composites, a mass fraction of 60 % UPHM resin was blended with a mass fraction of 40 % as-made (am-ACP) or ground ACP (g-ACP). DVC values of copolymer (unfilled UPHM resin) and composite specimens were determined by infrared spectroscopy. Glass-filled composites were used as controls. PS and PSS of composites were determined by dilatometry and tensometry, respectively. LC copolymers attained extraordinary high DVC values at 24 h post-cure (95.7 %), compared to CC (52 %) and DC (79.3 %) copolymer specimens. While the DVC values of LC and DC am-ACP composites were reduced between 5 and 10 %, DVC values of DC g-ACP composites increased almost 8 % compared to the corresponding copolymers. High DVC attained in LC composites was, expectedly, accompanied with high PS values (on average 7 vol%). However, PSS developed in LC and especially DC composites did not exceed PSS values seen in other UDMA-based composites. Based on this initial evaluation, it is concluded that, DC, g-ACP filled UPHM composite shows promise as an endodontic sealer. However, further physicochemical evaluations, including water sorption, mechanical stability and ion release as well as a leachability studies need to be performed before this experimental material is tested for cellular responses and, eventually recommended for clinical utility.
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Desbrieres, Jacques, Stephanie Reynaud, Pierre Marcasuzaa i Francis Ehrenfeld. "Actuator-Like Hydrogels Based on Conductive Chitosan". Advances in Science and Technology 84 (wrzesień 2012): 29–38. http://dx.doi.org/10.4028/www.scientific.net/ast.84.29.
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Intrinsically conducting polymers are of great interest for a large number of applications. But among major drawbacks are their low solubility in common solvents and their poor mechanical properties. Elaboration of composites associating a matrix, bringing its mechanical properties, and polyaniline, as the conducting polymer is a way of overcoming these disadvantages. Chitosan-graft-polyaniline copolymers were synthesized by simple oxidative method. The grafting reaction was quite total and it was found that the copolymers crosslinked to yield a composite hydrogel in which the polyaniline was homogeneously embedded. The conductivity of precursor (block copolymer) and gels was found to be larger than 10-2 S.cm-1. The composite gels were characterized in terms of swelling and rheological properties. They can be classified as "superabsorbent" hydrogels and the swelling is reversible. The composite gels were then successfully used as actuators.
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Liu, Fei, Shan Lu, Weihong Cao, Juncheng Huang, Yi Sun, Yiting Xu, Meiling Chen, Haining Na i Jin Zhu. "Using Cellulose-graft-Poly(L-lactide) Copolymers as Effective Compatibilizers for the Preparation of Cellulose/Poly(L-lactide) Composites with Enhanced Interfacial Compatibility". Polymers 14, nr 17 (24.08.2022): 3449. http://dx.doi.org/10.3390/polym14173449.
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Cellulose-grafte-poly(L-lactide) (C-g-PLLA) copolymers synthesized in a CO2-switchable solvent are proposed for use as effective compatibilizers for the preparation of cellulose–PLLA composites with enhanced interfacial compatibility. The effect of the molar substitution (MSPLLA) of the grafted PLLA side chain in the C-g-PLLA copolymer and the feeding amount of this copolymer on the mechanical and thermal properties and hydrophilicity of the composites was investigated. The composites had a largely increased impact strength with the incorporation of the compatibilizer. With the increasing of MSPLLA and the feeding amount of the copolymer, the resulting composites had an increased impact strength. When 5 wt% C-g-PLLA with MSPLLA of 4.46 was used as a compatibilizer, the obtained composite containing 20 wt% cellulose presented an impact strength equal to that obtained for the neat PLLA. The composites had a slightly decreased melting temperature and thermal decomposition temperature, but increased hydrophilicity due to the incorporation of the compatibilizer. This work suggests an effective method to improve the interfacial compatibility between cellulose and PLLA for the fabrication of fully bio-based composites with high performance.
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Piggott, M. R., i W. (Vincent) Zhou. "Shrinkage Control in Fibre Reinforced Polymers III: Carbon Fibre Reinforced Polyesters with Expanding Monomers and Low Profile Additives". Engineering Plastics 3, nr 6 (styczeń 1995): 147823919500300. http://dx.doi.org/10.1177/147823919500300601.
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Copolymers of polyester were made with two spiro orthocarbonates: cyclohexane and cyclohexene. They were also used to make unidirectional carbon fibre composites, and the properties of polymers and composites were compared with those made with a low profile additive (a copolymer of methyl and allyl methacrylates). The copolymers were not effective in reducing the shrinkage stress of the resin, except through a reduction in glass transition temperature. They gave composites with poor properties. The low profile additive was effective in reducing the shrinkage volume, but at the cost of a reduction in tensile strength. It did not affect the shrinkage stress very much, and did not have much effect on composite properties. Thus, while it is advantageous to use low profile additives with reinforced polyesters, it is not beneficial to use spiro orthocarbonate expanding monomers. Overall, the three papers in this series strongly suggest that, while controlling shrinkage stress may well be useful, it cannot be realized to any useful extent by using expanding monomers.
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Piggott, M. R., i W. (Vincent) Zhou. "Shrinkage Control in Fibre Reinforced Polymers III: Carbon Fibre Reinforced Polyesters with Expanding Monomers and Low Profile Additives". Polymers and Polymer Composites 3, nr 6 (wrzesień 1995): 395–402. http://dx.doi.org/10.1177/096739119500300601.
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Copolymers of polyester were made with two spiro orthocarbonates: cyclohexane and cyclohexene. They were also used to make unidirectional carbon fibre composites, and the properties of polymers and composites were compared with those made with a low profile additive (a copolymer of methyl and allyl methacrylates). The copolymers were not effective in reducing the shrinkage stress of the resin, except through a reduction in glass transition temperature. They gave composites with poor properties. The low profile additive was effective in reducing the shrinkage volume, but at the cost of a reduction in tensile strength. It did not affect the shrinkage stress very much, and did not have much effect on composite properties. Thus, while it is advantageous to use low profile additives with reinforced polyesters, it is not beneficial to use spiro orthocarbonate expanding monomers. Overall, the three papers in this series strongly suggest that, while controlling shrinkage stress may well be useful, it cannot be realized to any useful extent by using expanding monomers.
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Yang, Chongling, Shouzai Tan, Gengen Chen i Litao Guan. "Preparation and Characterization of PA6-PEG/Li High Performance Static Dissipation Composites". Australian Journal of Chemistry 70, nr 6 (2017): 669. http://dx.doi.org/10.1071/ch16288.
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A copolymer of PA6 (polyamide 6) and PEG (polyethylene glycol) was synthesized by a condensation reaction. The optimal reaction conditions were determined as the following: a reaction temperature of 255°C, –0.04 MPa vacuum, and a condensation time of 40 min. A series of novel PA6-PEG/Li composites were developed by melt blending the PA6-PEG copolymer (10 wt-% PEG) with three different kinds of colourless lithium salts (LiCl, C18H35LiO2, LiAc). FT-IR, NMR, thermogravimetric (TGA), electronic universal testing, and resistivity analyses were employed to investigate the comprehensive properties of the copolymers and composites. The results of FT-IR and 1H NMR analyses revealed that the PEG was copolymerized with PA6 successfully. TGA results indicated that the decomposition temperature of the PA6-PEG copolymer was above 350°C. Resistivity testing revealed that the surface resistivity (Rs) of the copolymer decreased from 1 × 1014 to 5.67 × 109 Ω square–1 with an increase of the content of PEG. The PA6-PEG/LiCl composite showed an excellent static dissipation performance of 2.71 × 108 Ω square–1.
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Mamedli, S. B. "PREPARATION OF OPTICAL TRANSPARENT COMPOSITES ON THE BASIS OF BUTYL METHACRYLATE WITH -METHYL STYRENE". Azerbaijan Chemical Journal, nr 1 (15.03.2022): 34–40. http://dx.doi.org/10.32737/0005-2531-2022-1-34-40.
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The process of radical binary copolymerization of butyl methacrylate and α-methyl styrene in a solvent has been carried out and optically transparent copolymers at various molar ratios have been synthesized. The copolymers synthesized based on butyl methacrylate and α-methyl styrene have relatively high refraction coefficient ( =1.5880) and transmission values (about 86%). The copolymerization constants values (r1 and r2) of the above-mentioned monomer pairs have been found and Q-e parameters have been calculated. The microstructure of the obtained copolymer samples of the butyl methacrylate with α-methyl styrene has been determined
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Allahverdiyeva, K. V. "Adhesive properties of aluminum-containing functionalized polymer composites obtained in the process of mechano-chemical modification". Perspektivnye Materialy 10 (2021): 27–36. http://dx.doi.org/10.30791/1028-978x-2021-10-27-36.
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The influence of the concentration of finely dispersed aluminum and compatibilizer on the resistance to peeling of aluminum foil from the surface of a composite based on low density polyethylene and high density polyethylene is considered. To improve the compatibility of the filler with the polymer matrix, a compatibilizer was used, which is a graft copolymer of polyethylene of various grades with methacrylic acid and maleic anhydride. Copper and aluminum foil was used as a substrate. It is shown that the introduction of a compatibilizer into the composition of aluminum-filled composites improves their peeling resistance. It has been found that if an aluminum filled compatibilizer is used directly as an adhesive, then the peeling resistance of copper and aluminum foil is significantly increased. Graft copolymers of polyethylene with maleic anhydride have the highest peel resistance values. The results of the study of the influence of the pressing temperature on the type of adhesive failure are presented. It is shown that with an increase in the pressing temperature, a mixed type of adhesive destruction is observed. It has been experimentally proved that, in percentage terms, the cohesive type of fracture prevails in composites where graft copolymers are used as a polymer matrix. It was found that a 100 % cohesive type of fracture is observed in foil-clad composites pressed at a temperature of 190 °C, where a graft copolymer of polyethylene with methacrylic acid or maleic anhydride is used as an adhesive.
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Zhou, Xiaodong, Qunfang Lin, Ruohua Xiong, Xinyu Cui i Gance Dai. "Effect of Flexible Polymer Coating on Interfacial Adhesion of Glass Fibre Reinforced Polypropylene". Polymers and Polymer Composites 13, nr 6 (wrzesień 2005): 619–25. http://dx.doi.org/10.1177/096739110501300607.
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Polymer coatings were obtained by using two rubbers, cis-polybutadiene rubber and ethylene-propylene diene monomer and two block copolymer: polystyrene-block-polybutadiene-block-polyvinyltriethoxysilane and polystyrene -block-polyvinyltrietho xysilane. They were used to coat glass fibre surfaces. The effects of the coatings on the interfacial adhesion and thermal cycling resistance of composites were studied by a single-filament fragmentation technique designed to measure the interfacial shear strength of glass fibre reinforced polypropylene. The interfacial shear strength was improved by the rubber coatings, which could graft to silane coupling agents coated onto the fibre surfaces, and could undergo crosslinking under peroxide initiation. The interfacial bond strength was determined by the nature and thickness of the rubber coatings. The interfacial adhesion was also improved when using block copolymers to treat glass fibres. The rubbers and those copolymers having flexible blocks in their chain structures both produced coatings that could relieve the thermal stresses at the composite interface during temperature cycling. The interface between the composites and the flexible polymer coatings had good thermal cycling fatigue resistance.
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Fan, Xiaoguang, Liyan Wu i Lei Yang. "Fabrication and characterization of thermoresponsive composite carriers: PNIPAAm-grafted glass spheres". e-Polymers 21, nr 1 (1.01.2021): 222–33. http://dx.doi.org/10.1515/epoly-2021-0023.
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Abstract Processing capacity and product yield of three-dimensional (3D) smart responsive carriers are markedly superior to those of two-dimensional substrates with the same compositions due to the special structure; therefore, more attempts have been made to develop the 3D intelligent systems in recent decades. A novel preparation strategy of thermoresponsive glass sphere-based composite carriers was reported in this study. First, PNIPAAm copolymers were synthesized by free-radical polymerization of N-isopropylacrylamide (NIPAAm), hydroxypropyl methacrylate (HPM), and 3-trimethoxysilypropyl methacrylate (TMSPM). Then, the copolymer solution was sprayed on the surfaces of glass spheres using a self-made bottom-spray fluidized bed reactor, and the bonding between copolymers and glass spheres was fabricated by thermal annealing to form PNIPAAm copolymer/glass sphere composite carriers. The coating effects of PNIPAAm copolymers on sphere surfaces were investigated, including characteristic functional groups, surface microstructure, grafting density, equilibrium swelling, as well as biocompatibility and potential application for cell culture. The results show that the temperature-responsive PNIPAAm copolymers can be linked to the surfaces of glass spheres by bottom-spray coating technology, and the copolymer layers can be formed on the sphere surfaces. The composite carriers have excellent thermosensitivity and favorable biocompatibility, and they are available for effective cell adhesion and spontaneous cell detachment by the use of smart responsiveness.
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Gutarowska, Beata, Renata Kotynia, Dariusz Bieliński, Rafał Anyszka, Jakub Wręczycki, Małgorzata Piotrowska, Anna Koziróg, Joanna Berłowska i Piotr Dziugan. "New Sulfur Organic Polymer-Concrete Composites Containing Waste Materials: Mechanical Characteristics and Resistance to Biocorrosion". Materials 12, nr 16 (15.08.2019): 2602. http://dx.doi.org/10.3390/ma12162602.
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The aim of this study was to develop new sulfur-copolymer concrete composites using waste compounds that have good mechanical characteristics and show a resistance to biocorrosion. The comonomers used to synthesize the sulfur–organic copolymers were—90 wt. % sulfur; 5 wt. % dicyclopentadiene (DCPD); 5 wt. % organic monomers, styrene (SDS), 1-decene (SDD), turpentine (SDT), and furfural (SDF). The concrete composites based on sulfur–organic copolymers were filled with aggregates, sand, gravel, as well as additives and industrial waste such as fly ash or phosphogypsum. The sulfur–organic copolymers were found to be chemically stable (softening temperature, thermal stability, melting temperature, amount of recrystallized sulfur, and shore D hardness). Partial replacement of DCPD with other organic comonomers did not change the thermal stability markedly but did make the copolymers more elastic. However, the materials became significantly stiffer after repeated melting. All the tested copolymers were found to be resistant to microbial corrosion. The highest resistance was exhibited by the SDS-containing polymer, while the SDF polymer exhibited the greatest change due to the activity of the microorganisms (FTIR analysis and sulfur crystallization). The concrete composites with sulfur–organic copolymers containing DCPD, SDS, SDF, fly ash, and phosphogypsum were mechanically resistant to compression and stretching, had low water absorbance, and were resistant to factors, such as temperature and salt. Resistance to freezing and thawing (150 cycles) was not confirmed. The concrete composites with sulfur–organic copolymers showed resistance to bacterial growth and acid activity during 8 weeks of incubation with microorganisms. No significant structural changes were observed in the SDS composites after incubation with bacteria, whereas composites containing SDF showed slight changes (FTIR and microscopic analysis). The concrete composite containing sulfur, DCPD, SDS, sand, gravel, and fly ash was the most resistant to microbiological corrosion, based on the metabolic activity of the bacteria and the production of ergosterol by the molds after eight weeks of incubation. It was found that Thiobacillus thioparus was the first of the acidifying bacteria to colonize the sulfur concrete, decreasing the pH of the environment. The molds Penicillium chrysogenum, Aspergillus versicolor and Cladosporium herbarum were able to grow on the surface of the tested composites only in the presence of an organic carbon source (glucose). During incubation, they produced organic acids and acidified the environment. However, no morphological changes in the concretes were observed suggesting that sulfur–organic copolymers containing styrene could be used as engineering materials or be applied as binders in sulfur-concretes.
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El-Aassar, Mohamed R., Tamer M. Tamer, Mohamed Y. El-Sayed, Ahmed M. Omer, Ibrahim O. Althobaiti, Mohamed E. Youssef, Rawan F. Alolaimi, Emam F. El-Agammy, Manar S. Alruwaili i Mohamed S. Mohy-Eldin. "Development of Azo Dye Immobilized Poly (Glycidyl Methacrylate-Co-Methyl Methacrylate) Polymers Composites as Novel Adsorbents for Water Treatment Applications: Methylene Blue-Polymers Composites". Polymers 14, nr 21 (2.11.2022): 4672. http://dx.doi.org/10.3390/polym14214672.
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Methylene blue azo dye (MB) immobilized onto Poly (glycidyl methacrylate-Co-methyl methacrylate), (PGMA-co-PMMA), and sulphonated Poly (glycidyl methacrylate-Co-methyl methacrylate), (SPGMA-co-PMMA), polymers composites have been developed as novel adsorbents for water treatment applications. The effect of copolymer composition and sulphonation on the MB content has been studied. Maximum MB content was correlated to the Polyglycidyl methacrylate content for both native and sulphonated copolymers. Furthermore, the effect of the adsorption conditions on the MB content was studied. Sulfonated Poly (glycidyl methacrylate; SPGMA) was the most efficient formed composite with the highest MB content. The developed composites’ chemical structure and morphology were characterized using characterization tools such as particle size, FTIR, TGA, and SEM analyses. The developed MB-SPGMA composite adsorbent (27 mg/g), for the first time, was tested for the removal of Cr (VI) ions and Mn (VII) metal ions from dichromate and permanganate contaminated waters under mild adsorption conditions, opening a new field of multiuse of the same adsorbent in the removal of more than one contaminants.
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Davis, Cher, i Drago Skrtic. "Determination of leachable components from an experimental endodontic sealer by nuclear magnetic resonance (NMR) spectroscopy". Serbian Dental Journal 58, nr 4 (2011): 187–201. http://dx.doi.org/10.2298/sgs1104187d.
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Introduction. Studies of experimental composites based on amorphous calcium phosphate (ACP) intended for dental applications as remineralizing pit and fissure sealants, orthodontic adhesives and, most recently, endodontic sealers were mainly focused on improving their mechanical, esthetic and remineralizing capabilities. Similar to the vast majority of commercial composites, these experimental formulations might have clinical drawbacks due to incomplete conversion of monomers and leachability of monomers and degradation products, shrinkage and stress associated with polymerization, and microleakage typically occurring at the tooth/composite interfacial region. The aim of this study was to identify and quantify leachable components from the experimental amorphous calcium phosphate (ACP) endodontic sealer using 1H nuclear magnetic resonance (NMR) spectroscopy. Material and Methods. The light-cure resin [camphorquinone (CQ) + ethyl-4-N,N-dimethylamino benzoate (4EDMAB)] was formulated from urethane dimethacrylate (UDMA), poly(ethylene glycol)- extended urethane dimethacrylate (PEG-U), 2-hydroxyethyl methacrylate (HEMA) and methacryloyloxyethyl phthalate (MEP). The experimental sealer contained 40 mass % ground ACP and 60 mass % resin. The copolymer (unfiled resin) and ACP/UPHM composite specimens, after being dried to a constant mass, were extracted in butylated hydroxyl toluene (BHT; prevents polymerization of eluted components) containing acetone for 7 days at 23?C with continuous magnetic stirring. Gravimetric changes were recorded for each specimen. After solvent evaporation, 1H NMR spectra were collected on the extractable portion of each specimen. Representative peaks for each component were used to calculate their relative portions in the extracts. By combining the gravimetric and NMR data, the overall loss of each monomer and its concentration in the extract was calculated. Results were statistically analyzed by ANOVA and multiple pair-wise comparisons (t-test). Results. No CQ could be detected in the extracts. However, 33.06 % and 24.66 % of the initially incorporated 4EDMleached from the copolymers and composites, respectively. 0.30-14.29% and 0.12-10.39% of each monomer content leached out from copolymers and composites, respectively. The apparent differences in the concentrations between copolymers and composites became marginal when composite data were normalized with respect to the initial amount of the resin. Conclusion. 1H NMR conveniently provides qualitative and quantitative information on leachables without the elaborate sample preparation and/or data interpretation. Leachability of the unrectaed monomers from the experimental ACP sealer is apparently controlled by the highly cross-linked resin network and unaffected by the incorporation of bioactive ACP into the resin. The maximum levels of leachables from our experimental composite were within or below the concentration ranges reported for the commercial counterparts.
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Ouyang, Mi, Zhen Wei Yu, Yi Xu, Yu Jian Zhang i Cheng Zhang. "Electrochemically Synthesis and Characterization of Copolymers Based on 1, 4-Diethoxybenzene and 3, 4-Ethylenedioxythiophene". Advanced Materials Research 335-336 (wrzesień 2011): 989–93. http://dx.doi.org/10.4028/www.scientific.net/amr.335-336.989.
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Copolymers based on 1, 4-diethoxybenzene (DEB) and 3, 4-ethylenedioxythiophene (EDOT) were electrochemically synthesized and characterized. The structures of the copolymers were established by 1H NMR and FT-IR spectroscopy. The results indicated the final product was a copolymer instead of a blend or a composite. The physical properties were systematically investigated by cyclic voltammetry, UV-vis absorption and fluorescence. The PL maximum of copolymers presented obviously red-shift to long wavelength as the feed ratio of EDOT in monomer mixture increased.
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Azimi, Hamid Reza, Mostafa Rezaei i Mostafa Salehi. "The effect of copolymer composition on the batch foaming dynamics of styrene/methylmethacrylate copolymers". Journal of Thermoplastic Composite Materials 30, nr 1 (5.08.2016): 47–66. http://dx.doi.org/10.1177/0892705715575095.
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In this work, styrene/methyl methacrylate (St/MMA) copolymer particles were synthesized by suspension polymerization process with different copolymer compositions to study the visual batch foaming dynamics. The visualization system consisted of the self-sealing observation cell equipped to the pressure and temperature controller. The synthesized copolymer particles were impregnated by n-pentane, followed by recording of particle expansion. The cell structure of foams was studied by scanning electron microscopy. The effect of different foaming conditions on the expansion behavior of copolymers was examined. It was concluded that sorption pressure and temperature have contradictory effects on the foaming ratio of the synthesized copolymers at lower and higher sorption pressures, and the results were confirmed with the foams’ cell structure. Furthermore, it was shown that, at different temperatures and pressures, the expansion behavior change dramatically with increasing of MMA content in the copolymer.
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Semsarzadeh, Mohammad Ali, Arezoo Sh Dadkhah i Alireza sabzevari. "High-performance family of polymeric particles prepared from poly(phenylene oxide)-poly(hexyl isocyanate) liquid crystal block copolymer: synthesis and properties study". Polymers and Polymer Composites 30 (styczeń 2022): 096739112211046. http://dx.doi.org/10.1177/09673911221104678.
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The poly (phenylene oxide)-block-poly (hexyl isocyanate) copolymers (PPO-b-PHIC)s were synthesized in various ratios of blocks using the organotitanium coordination method at room temperature. The copolymer particles were prepared by precipitation of concentrated solution of the copolymers in non-solvent under stirring. The synthesized copolymers and their particles were characterized by 1H and 13C nuclear magnetic resonance (1H and 13C NMR), Fourier transform infrared (FTIR) spectra, differential scanning calorimetry (DSC), polarized optical microscope (POM), thermogravimetric analysis (TGA) and scanning electron microscope (SEM). The effect of block ratio on the anisotropic-isotropic transition and liquid crystal texture of copolymers as a function of temperature and concentration of the solution was investigated. The polymeric particles tend to be aligned along the fibrillar direction by increasing the block ratio of amide in the copolymer.
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Guo, Wei, Zicheng Zheng, Wei Li, Hao Li, Fankun Zeng i Huajie Mao. "The Cellular Structure and Toughness of Hydrogenated Styrene-Butadiene Block Copolymer Reinforced Polypropylene Foams". Polymers 15, nr 6 (17.03.2023): 1503. http://dx.doi.org/10.3390/polym15061503.
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Polypropylene nanocomposites containing varying amounts of Styrene-ethylene-butadiene-styrene block copolymer (SEBS) were prepared through the supercritical nitrogen microcellular injection-molding process. Maleic anhydride (MAH)-grafted polypropylene (PP-g-MAH) copolymers were used as compatibilizers. The influence of SEBS content on the cell structure and toughness of the SEBS/PP composites was investigated. Upon the addition of SEBS, the differential scanning calorimeter tests revealed that the grain size of the composites decreased, and their toughness increased. The results of the rheological behavior tests showed that the melt viscosity of the composite increased, playing a role in enhancing the cell structure. With the addition of 20 wt% SEBS, the cell diameter decreased from 157 to 66.7 μm, leading to an improvement in the mechanical properties. Compared to pure PP material, the impact toughness of the composites rose by 410% with 20 wt% of SEBS. Microstructure images of the impact section displayed evident plastic deformation, effectively absorbing energy and improving the material’s toughness. Furthermore, the composites exhibited a significant increase in toughness in the tensile test, with the foamed material’s elongation at break being 960% higher than that of pure PP foamed material when the SEBS content was 20%.
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Skorokhoda, Volodymyr, Nataliya Semenyuk, Iryna Dziaman i Oleg Suberlyak. "Mineral Filled Porous Composites Based on Polyvinylpyrrolidone Copolymers with Bactericidal Properties". Chemistry & Chemical Technology 10, nr 2 (15.06.2016): 187–92. http://dx.doi.org/10.23939/chcht10.02.187.
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The polymerization of 2-hydroxyethylmethacrylate compositions with polyvinylpyrrolidone has been investigated in the presence of mineral fillers (hydroxyapatite, montmorillonite and wollastonite). The influence of the nature and amount of mineral filler on polymerization kinetics and composition of copolymers has been determined. In the composite structure silver particles were obtained via silver nitrate reduction by polyvinylpyrrolidone tertiary nitrogen. The synthesized silver-containing composites possess bactericidal properties against E. colі and S. aureus bacteria, in particular.
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Rajalingam, P., i W. E. Baker. "The Role of Functional Polymers in Ground Rubber Tire-Polyethylene Composite". Rubber Chemistry and Technology 65, nr 5 (1.11.1992): 908–16. http://dx.doi.org/10.5254/1.3538650.
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Abstract The impact energies of different polyethylene-ground rubber tire (GRT) composites were investigated. All the thermoplastic composites were prepared on a Haake Buchler batch mixer and injection molded test specimens were tested on Rheometrics drop weight instrumented impact tester. Addition of small amounts of functional polymers increases the impact energy of the polyethylene-GRT composite as much as 60%. The percent improvement in the impact energy for linear low density polyethylene (LLDPE) and the composites prepared from them is greater than for the corresponding high density polyethylene (HDPE) composites. Precoating of GRT particles with ethylene-acrylic acid (EAA) copolymers improves the impact energy of the composite, whereas precoating with the other functional polymers does not. An attempt has been made to identify the role of the functional polymers as to whether they act as toughening agents for the polyethylene matrix or coupling agent at the polyethylene-GRT interface. The results show the increase in impact energy resulting from the addition of styrene block copolymers is due to toughening of the polyethylene matrix while the reactive ethylene copolymers increase the impact energy by a coupling action with GRT.
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Shibata, Mitsuhiro, Ryutoku Yosomiya, Junzuo Wang, Chunhai Chen, Guohong Bai, Zhongwen Wu, Shanger Wang i Zhishen Mo. "Synthesis and Properties of Block Copolymers of Poly(ether sulphone)s with Liquid Crystalline Polyester Units". Polymers and Polymer Composites 5, nr 1 (styczeń 1997): 1–5. http://dx.doi.org/10.1177/096739119700500101.
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Block copolymers of poly(ethersulphone) (PES) oligomers with liquid crystalline polyester units were synthesized by the reaction of dihydroxy-terminated poly(ether sulphone) oligomers (number-average molecular weights: 704, 1,158 and 2570) and terephthaloyl bis(4-oxybenzoyl chloride), and their properties were investigated. The results indicated that the copolymer with PES segments of molecular weight of 704 possessed birefringent features when annealed at 360°C, while the copolymer with PES segments of molecular weight of 2,570 became isotropic. Also, the block copolymers had a better chemical resistance and high-temperature stability than PES.
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Skrtic, Drago, S. Y. Lee, Joseph M. Antonucci i D. W. Liu. "Amorphous Calcium Phosphate Based Polymeric Composites: Effects of Polymer Composition and Filler's Particle Size on Composite Properties". Key Engineering Materials 284-286 (kwiecień 2005): 737–40. http://dx.doi.org/10.4028/www.scientific.net/kem.284-286.737.
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This study explores how a) the resin grafting potential for amorphous calcium phosphate (ACP) and b) particle size of ACP affects physicochemical properties of composites. Copolymers and composites were evaluated for biaxial flexure strength (BFS), degree of vinyl conversion (DC), mineral ion release and water sorption (WS). Milled ACP composites were superior to unmilled ACP composites and exhibited 62 % and 77 % higher BFS values (dry and wet state, respectively). The average DC of copolymers 24 h after curing was 80 %. DC of composites decreased 10.3 % for unmilled Zr-ACP and 4.6 % for milled Zr-ACP when compared to the corresponding copolymers. The WS increased as follows: copolymers < milled Zr-ACP composites < unmilled Zr-ACP composites. The levels of Ca and PO4 released from both types of composites increased with the increasing EBPADMA/TEGDMA ratio in the matrix. They were significantly above the minimum necessary for the redeposition of HAP to occur. No significant consumption of released calcium by the carboxylic groups of methacryloxyethyl phtahalate (MEP) occurred at a mass fraction of 2.6 % of MEP in the resin. Improvements in ACP composite’s physicochemical properties are achieved by fine tuning of the resin and improved ACP’s dispersion within the polymer matrix after ball-milling.
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Lin, Hu Bin, Chong Min Du, Jian Yi Zhu i Wen Yao Liang. "Morphology and Mechanical Properties of Compatibilized β Nucleated Polypropylene/Polystyrene Blends". Advanced Materials Research 902 (luty 2014): 63–65. http://dx.doi.org/10.4028/www.scientific.net/amr.902.63.
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The β nucleated polypropylene (PP), uncompatibilized β nucleated PP/polystyrene (PS) and compatibilized β nucleated PP/PS blends were prepared on a twinscrew extruder.and then,added into compatibilizers styrene-ethylene-propylene block copolymer (SEP) or twostyrene-ethylene-butylene-styrene block copolymers (SEBS) with different content of styrene.The morphology and mechanical properties of these composites were investigated.
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Wang, Chaoyang. "Synthesis of Multiblock Copolymers of Poly(2-vinylpyridine) and Polyoxyethylene and their Application as Compatibilizers for Epichlorohydrin Rubber/Poly(Vinyl Chloride) Blends". Polymers and Polymer Composites 13, nr 2 (luty 2005): 191–98. http://dx.doi.org/10.1177/096739110501300208.
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Multiblock copolymers of poly(2-vinylpyridine) (P2-VP) and polyoxyethylene (PEO) were synthesized by condensing telechelic dihydroxy poly(2-vinylpyridine) (THPVP) and PEO with dichloromethane in the presence of potassium hydroxide. The copolymers were purified by extraction with water and toluene successively and characterized by Fourier Transform Infrared Spectroscopy and nuclear magnetic resonance spectroscopy. The block copolymers behave as good compatibilizers for the blending of epichlorohydrin rubber (CHR) with poly(vinyl chloride) (PVC). The addition of approximately 2-3% block copolymer to the blends evidently improves their mechanical properties and causes the two glass transition temperatures ( Tg) to become closer. The blends with a weight ratio PVC/CHR of 4/6 and the addition of 2-4% block copolymer show mechanical properties consistent with those of a thermoplastic elastomer.
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Ghumman, Ali Shaan Manzoor, Rashid Shamsuddin, Mohamed Mahmoud Nasef, Carmelo Maucieri, Obaid Ur Rehman, Arief Aizat Rosman, Mohamed Izzat Haziq i Amin Abbasi. "Degradable Slow-Release Fertilizer Composite Prepared by Ex Situ Mixing of Inverse Vulcanized Copolymer with Urea". Agronomy 12, nr 1 (28.12.2021): 65. http://dx.doi.org/10.3390/agronomy12010065.
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To improve the crop yield and nitrogen uptake efficacy, a novel slow-release urea composite fertilizer (SUCF) was developed using inverse vulcanized copolymer with better biodegradation and nutrient release longevity. Copolymers were synthesized via inverse vulcanization of jatropha oil, and their properties were evaluated using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), powdered-X-ray diffractometry (p-XRD), and scanning electron microscopy (SEM). SUCFs were developed by ex situ mixing of inverse vulcanized copolymer with urea powder using mechanical mixer, and their properties were evaluated using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR spectra of developed fertilizer possesses the urea characteristics peaks along with the undisturbed peaks representing copolymer, confirming the mechanical mixing and that no reaction took place. SEM images of the SUCFs compared with images of copolymer revealed the appearance of new isolated particles with different morphology; EDX mapping showed that these particles represent the urea added to the copolymer. Nitrogen release longevity of developed fertilizers was evaluated in both soil and distilled water. The leaching test revealed that only 70% of the total nitrogen of SUCF prepared from 50 wt% sulfur copolymer was released after 16 days of incubation in distilled water, whereas it released only 35% nitrogen after 20 days in soil. The biodegradability of all copolymers developed was investigated by burying in soil and it revealed their biodegradable nature as weight loss was observed, which increased with the increase of incubation period.
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Wang, Zihao, Susu Tao, Yanyan Chu, Xiaoyan Xu i Qinggang Tan. "Diameter of Carbon Nanotube-Directed Self-Assembly of Amphiphilic Block Copolymers". Materials 12, nr 10 (16.05.2019): 1606. http://dx.doi.org/10.3390/ma12101606.
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The cooperative self-assembly of nanoparticles and amphiphilic block copolymers has attracted increasing interests as it offers effective routes to achieve nanocomposite supramolecular structures with desired structure and properties. The incorporation of nanoparticles usually tunes the self-assembly structure of block copolymers, as the copolymer–nanoparticle interactions may change the relative volume ratio of hydrophobic block/hydrophilic block copolymers. It should be noted that the micro-size length and the strong nonpolar feature of carbon nanotubes (CNTs) may cause the block copolymer–CNT interactions to differ from the the block copolymer–nanoparticle interactions. Herein, we show that the diameter of CNTs and the copolymer/CNT ratio have a profound effect on the self-assembly behavior of amphiphilic block copolymers. Upon the addition of carboxylated multi-walled carbon nanotubes (c-MWCNTs, diameter <8 nm,) to the methoxy polyethylene glycol-poly (D,L-lactic acid) (MPEG-PDLLA) solution, it is difficult to observe the c-MWCNTs directly in TEM images. However, it has been found that they form supramolecular nanocomposite structures with MPEG-PDLLA. Moreover, these supramolecular structures transform from core–shell spherical micelles into rod-like micelles and then into large composite aggregates with the increase of the c-MWCNT addition. However, in the case of the addition of c-MWCNTs with a diameter of 30–50 nm, the dispersed c-MWCNTs and spherical core–shell micelles could be observed simultaneously in the TEM images at a low c-MWCNT addition, and then the micelle structure disappeared and only well-dispersed c-MWNTs were observed in TEM images at a high c-MWCNT addition. A possible model was proposed to explain the rule of CNTs participating in the formation of copolymer/CNT nanocomposite structures. It was also shown that as-prepared copolymer/CNT supramolecular nanocomposites could be used as drug carriers, enabling the adjustment of the drug loading and release time.
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Grytsenko, Oleksandr, Ludmila Dulebova, Emil Spišák i Bohdan Berezhnyy. "New Materials Based on Polyvinylpyrrolidone-Containing Copolymers with Ferromagnetic Fillers". Materials 15, nr 15 (26.07.2022): 5183. http://dx.doi.org/10.3390/ma15155183.
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The article investigates the peculiarities of the effect of ferromagnetic fillers (FMFs) of various natures (Ni, Co, Fe, FeCo, SmCo5) on the formation of the structure and properties of 2-hydroxyethylmethacrylate (HEMA) with polyvinylpyrrolidone (PVP) copolymers. The composites were characterized using FTIR-spectroscopy, SEM, DMTA, magnetometry of vibrating samples, specific electrical resistivity studies, and mechanical and thermophysical studies. The formation of a grafted spatially crosslinked copolymer (pHEMA-gr-PVP) was confirmed and it was established that the FMF introduction of only 10 wt.% into the copolymer formulation increased the degree of crosslinking of the polymer network by three times. The surface hardness of composites increased by 20–25%. However, the water content decreased by 16–18% and lay within 42–43 wt.%, which is a relatively high number. The heat resistance of dry composites was characterized by Vicat softening temperature, which was 39–42 °C higher compared to the unfilled material. It was established that the obtained composites were characterized by a coercive force of 200 kA × m−1 and induction of a magnetic field at the poles of 4–5 mT and 10–15 mT, respectively. The introduction of FMF particles into pHEMA-gr-PVP copolymers, which, in the dry state, are dielectrics, provides them with electrical conductivity, which was evaluated by the specific volume resistance. Depending on the FMF nature and content, as well as their orientation in the magnetic field, the resistance of filled materials could be regulated within 102–106 Ohm·m. Therefore, the modification of HEMA with PVP copolymers by ferromagnetic fillers of various natures provides the possibility of obtaining materials with unique predicted properties and expands the fields of their use, for instance as magnetic sorbents for various applications, as well as the possibilities associated with their being electrically conductive materials that can respond by changing of electrical conductivity, depending on various factors.
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Lin, Hu Bin, Chong Ming Du, Jian Yi Zhu i Wen Yao Liang. "Non-Isothermal Crystallization Behavior and Kinetics of Compatibilized β Nucleated Polypropylene/Polystyrene Blends". Advanced Materials Research 893 (luty 2014): 291–94. http://dx.doi.org/10.4028/www.scientific.net/amr.893.291.
Pełny tekst źródłaStreszczenie:
The β nucleated polypropylene (PP), uncompatibilized β nucleated PP/polystyrene (PS) and compatibilized β nucleated PP/PS blends were prepared on a twinscrew extruder.and added into compatibilizers styrene-ethylene-propylene block copolymer (SEP) or two styrene-ethylene-butylen- e-styrene block copolymers (SEBS) with different content of styrene.The crystallization characteristic, melting behavior and crystallization kinetics of these composites were studied.
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Lim, Young Don, Dong Wan Seo, Soon Ho Lee, Md Monirul Islam, Hyun Mi Jin, Ho Hyoun Jang, Insuk Jeong i Whan Gi Kim. "Nano Composite Membranes of Sulfonated Poly(ether sulfone) Containing 4,4-Bis(4-hydroxylphenyl)valeric Acid and SiO2 for PEMFC". Materials Science Forum 695 (lipiec 2011): 37–40. http://dx.doi.org/10.4028/www.scientific.net/msf.695.37.
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Poly(ether sulfone)s (PES) containing 25-75 mol % valeric acid were prepared with bisphenol A, bis(4-chlorophenyl)sulfone and 4,4-Bis(4-hydroxylphenyl)valeric acid using potassium carbonate in DMAc (dimethylacetamide) at 160 °C. Copolymers containing carboxylacid group were reduced to hydroxy group by BH3solution 1M in THF and NaBH4 co-catalyst. Sulfonated poly(ether sulfone)s (S-PES) were obtained by reaction of 1,3-propanesultone and the reduced copolymer (PES-OH) with potassium t-butoxide. Composite membranes were prepared with copolymers and SiO2nanoparticles(20 nm, 4-10 wt%). The composite membranes were cast from DMSO.A series of composite membranes were studied by1H-NMR spectroscopy, differential scanning calorimetry (DSC), and thermo gravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction of sulfonated polymers with water and methanol.
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Dolza, Celia, Eloi Gonga, Eduardo Fages, Ramon Tejada-Oliveros, Rafael Balart i Luis Quiles-Carrillo. "Green Composites from Partially Bio-Based Poly(butylene succinate-co-adipate)-PBSA and Short Hemp Fibers with Itaconic Acid-Derived Compatibilizers and Plasticizers". Polymers 14, nr 10 (12.05.2022): 1968. http://dx.doi.org/10.3390/polym14101968.
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In this work, green composites have been developed and characterized using a bio-based polymeric matrix such as BioPBSA and the introduction of 30 wt.% short hemp fibers as a natural reinforcement to obtain materials with maximum environmental efficiency. In order to increase the interfacial adhesion between the matrix and the fiber to obtain better properties in the composites, a reactive extrusion process has been carried out. On the one hand, different additives derived from bio-based itaconic acid have been added to the BioPBSA/HEMP composite, such as dibutyl itaconate (DBI) and a copolymer of PBSA grafted with itaconic acid (PBSA-g-IA). On the other hand, a different copolymer of PBSA grafted with maleic anhydride (PBSA-g-MA) was also tested. The resulting composites have been processed by injection-molding to obtain different samples which were evaluated in terms of mechanical, thermal, chemical, dynamic-mechanical, morphological and wettability and color properties. In relation to the mechanical properties, the incorporation of hemp fibers resulted in an increase in the stiffness of the base polymer. The tensile modulus of pure BioPBSA increased from 281 MPa to 3482 MPa with 30% fiber. The addition of DBI shows a remarkable improvement in the ductility of the composites, while copolymers with IA and MA, generate mechanically balanced composites. In terms of thermal properties, the incorporation of hemp fiber and compatibilizing agents led to a reduction in thermal stability. However, from the point of view of thermomechanical properties, a clear increase in rigidity is achieved throughout the temperature range studied. As far as the color of the samples is concerned, the incorporation of hemp generates a typical color, while the incorporation of the compatibilizing agents does not modify this color excessively. Finally, the introduction of lignocellulosic fibers greatly affects water absorption and contact angle, although the use of additives helped to mitigate this effect.
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Kakhramanov, N. T., I. V. Bayramova, V. S. Osipchik, A. D. Ismayilzade, S. R. Abdalova, I. A. Ismayilov i U. V. Namazli. "PHYSICOMECHANICAL PROPERTIES OF NANOCOMPOSITES BASED ON COPOLYMERS OF ETHYLENE WITH α-OLEFINS AND CLINOPTILOLITE". Azerbaijan Chemical Journal, nr 4 (12.12.2020): 22–27. http://dx.doi.org/10.32737/0005-2531-2020-4-22-27.
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The results of studying the effect of clinoptilolite concentration on the properties of nanocomposites based on of ethylene with butylene and of ethylene with hexene copolymer are presented. The effect of clinoptilolite particle size on ultimate tensile stress, elongation at break, flexural modulus, heat resistance, and melt flow index of composites was studied. It is shown that nanocomposites based on ethylene copolymers are characterized by higher values of physicomechanical properties. The additional use of ingredients such as alizarin and calcium stearate contributes to a significant improvement in the complex of properties of nanocomposites based on ethylene copolymers and clinoptilolite
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Vladimirov, Nikolay G., i Ivan Gitsov. "Polymerization Initiated by Graphite Intercalation Compounds Revisited: One-Pot Synthesis of Amphiphilic Pentablock Copolymers". Macromol 2, nr 2 (14.05.2022): 184–93. http://dx.doi.org/10.3390/macromol2020012.
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This study reports the first attempt to employ a potassium–graphite intercalation compound (KC24) as an initiator for the one-pot synthesis of a multi-block copolymer. The results obtained show that KC24 successfully initiated the copolymerization, leading to a copolymer consisting of poly(styrene), poly(methyl methacrylate) and poly(ethylene oxide) blocks. When all three comonomers were introduced simultaneously or in a specific sequence, the resulting copolymers had molecular masses in the range between 170,000 Da and 280,000 Da. Their composition was investigated by size-exclusion chromatography with triple detection (dRI/UV/IR) and 1H-NMR. The analyses indicated that all copolymers were enriched in methyl methacrylate (50–66 mol%) despite the fact that the comonomers were added in equimolar amounts. Due to the layered structure of the initiator, the polymerization took place in the graphite interlayer spaces and lead to extensive delamination, indicating at the potential to produce in situ graphite/copolymer composite materials.
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Ren, Huanhuan, Zhankui Mei, Yangyang Chen, Shaojun Chen, Zaochuan Ge i Jinlian Hu. "Synthesis of zwitterionic acrylamide copolymers for biocompatible applications". Journal of Bioactive and Compatible Polymers 33, nr 1 (10.05.2017): 3–16. http://dx.doi.org/10.1177/0883911517707776.
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In order to prepare acrylamide copolymers with non-toxicity for environment-friendly materials, a series of zwitterionic acrylamide copolymers with varying acrylamide content were synthesized with DMAPS (3-dimethyl (methacryloyloxyethyl) ammonium propane sulfonate) and acrylamide via free radical polymerization. The structural properties and cytotoxicity are carefully investigated. The results demonstrate that DMAPS- co-acrylamide copolymers contain DMAPS and acrylamide segments that form a matrix consisting of strong electrostatic interactions as well as strong hydrogen bonding. DMAPS segments exhibit negligible influence on the glass phase transition behavior, yet affect the composite’s water-contact angle. The optimum hydrophilic properties are obtained by adjusting the acrylamide content to 50 wt%. All DMAPS- co-acrylamide copolymers are measured to be non-toxic. The DMAPS segments allow for suitable contribution to the biocompatibility of the synthesized copolymer, in which copolymers containing higher DMAPS content demonstrate better biocompatibility.
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Zalina, A. L., J. A. Soboleva, D. V. Zakharova i I. P. Storozhuk. "Self-healing polyurethane-polypropylene oxide copolymers for the protection of carbon and glass fiber-reinforced composites". E3S Web of Conferences 413 (2023): 02036. http://dx.doi.org/10.1051/e3sconf/202341302036.
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Polyurethane-polypropylene oxide block copolymers containing fragments of an adduct capable of self-healing by the Diels-Alder reaction mechanism have been synthesized and studied for the first time. All obtained polyurethane copolymers were characterized by IR spectroscopy. The temperature transitions and thermal stability of copolymer melts were determined by using the methods of differential scanning calorimetry and thermogravimetric analysis. The self-healing effect was confirmed using a thermal cycling procedure on pre-damaged samples of modified polyurethanes and surface morphology studies. The perspective of the work begun on the creation of self-healing protective polyurethane coatings are shown.
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Lee, Dong Hoon, Hye Suk Park, Dong Wan Seo, Tae Whan Hong, Soon Chul Ur i Whan Gi Kim. "Synthesis and Characterization of Branched Sulfonated Poly(ether Sulfone-Ketone) Copolymer and Organic-Inorganic Nano Composite Membranes". Materials Science Forum 534-536 (styczeń 2007): 121–24. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.121.
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Branched sulfonated poly(ether sulfone-ketone) copolymer was prepared with bisphenol A, 4,4-difluorobenzophenone, sulfonated chlorophenyl sulfone (40mole% of bisphenol A) and THPE (1,1,1-tris-p-hydroxyphenylethane) as a branching agent. THPE was used 0.4 mol% of bisphenol A to synthesize branched copolymers. Organic-inorganic nano composite membranes were prepared with copolymer and a series of SiO2 nanoparticles (20 nm, 4, 7 and 10 wt%). The composite membranes were cast from dimethylsulfoxide solutions. The films were converted from the salt to acid forms with dilute hydrochloric acid. The membranes were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction of sulfonated polymers with water and methanol. Branched copolymer and nano composite membranes exhibited proton conductivities from 1.12x10-3 to 6.04x10-3 S/cm2, water uptake from 52.9 to 62.4%, IEC from 0.81 to 1.21 meq/g and methanol diffusion coefficients from 1.2x10-7 to 1.5x10-7 cm2/S.
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Tong, Wang Shu, Yi He Zhang, Li Yu, Jiao Hao i Feng Zhu Lv. "The Investigation of the PAM / St-g-PAA /Bentonite Superabsorbent Composite in Model of Rain Garden". Advanced Materials Research 374-377 (październik 2011): 1405–8. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.1405.
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The polyacrylamide/starch-acrylic acid graft copolymer/bentonite composites with different concentrations of the bentonite and starch-acrylic acid graft copolymer were prepared by in-situ polymerization. The influence of the concentration of the bentonite and starch-acrylic acid graft copolymer on the water absorbency was investigated. The water absorbency of 115 g/g could be achieved with the composite composed of 50wt% bentonite, 17wt% starch-acrylic acid graft copolymer and 33wt% polyacrylamide. The excellent absorption and retention performance of the composite makes it potential to be applied in the model of Rain garden.
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Hong, Haoqun, Quannan Guo, Haiyan Zhang i Hui He. "Effect of interfacial modifiers and wood flour treatment on the rheological properties of recycled polyethylene/wood flour composites". Progress in Rubber, Plastics and Recycling Technology 36, nr 1 (17.12.2019): 31–46. http://dx.doi.org/10.1177/1477760619895014.
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The article presents the preparation of a high-performance wood–plastic composites with improved interfacial interactions by adding ternary-monomer graft copolymers as the interfacial modifiers and by braising wood flour (WF) and investigates their effects on the rheological properties of recycled polyethylene (rPE)/WF composites. The processing properties, capillary rheological properties, dynamical rheological properties, and mechanical properties were investigated. Results show that graft copolymer of polyethylene is effective in improving the interfacial interactions of rPE/WF composites, dramatically changing the rheological and mechanical properties. The braising of WF enlarges the gaps of cells and promotes the infiltration of rPE into the gaps, as promoting the increasing in mechanical properties of rPE/WF composites and significantly changing the rheological properties of the composites.
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Grytsenko, O. M., L. Dulebova, N. M. Baran, T. O. Grytsenko i P. P. Voloshkevych. "Еlectrically conductive composite materials based on polyvinylpyrrolidone copolymers with combined fillers". Chemistry, Technology and Application of Substances 6, nr 1 (1.06.2023): 137–43. http://dx.doi.org/10.23939/ctas2023.01.137.
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Composite materials based on copolymers of polyvinylpyrrolidone and 2-hydroxyethylmethacrylate with combined fillers consisting of metal powders and graphite were obtained by the method of polymerization filling. The developed materials are characterized by sufficiently high physical and mechanical properties, increased electrical conductivity and water content. It was established that the addition of graphite to metal-filled copolymers increases the sensitivity of the electrical resistance of composites to moisture changes.
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Shahabi, Sima, Farhood Najafi, Abbas Majdabadi, Tabassom Hooshmand, Masoumeh Haghbin Nazarpak, Batool Karimi i Seyyed Mostafa Fatemi. "Effect of Gamma Irradiation on Structural and Biological Properties of a PLGA-PEG-Hydroxyapatite Composite". Scientific World Journal 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/420616.
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Gamma irradiation is able to affect various structural and biological properties of biomaterials In this study, a composite of Hap/PLGA-PEG and their ingredients were submitted to gamma irradiation doses of 25 and 50 KGy. Various properties such as molecular weight (GPC), thermal behavior (DSC), wettability (contact angle), cell viability (MTT assay), and alkaline phosphatase activity were studied for the composites and each of their ingredients. The results showed a decrease in molecular weight of copolymer with no change in the glass transition and melting temperatures after gamma irradiation. In general gamma irradiation can increase the activation energy ΔHof the composites and their ingredients. While gamma irradiation had no effect on the wettability of copolymer samples, there was a significant decrease in contact angle of hydroxyapatite and composites with increase in gamma irradiation dose. This study showed an increase in biocompatibility of hydroxyapatite with gamma irradiation with no significant effect on cell viability in copolymer and composite samples. In spite of the fact that no change occurred in alkaline phosphatase activity of composite samples, results indicated a decrease in alkaline phosphatase activity in irradiated hydroxyapatites. These effects on the properties of PLGA-PEG-hydroxyapatite can enhance the composite application as a biomaterial.
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Pandit, Rajesh, Albrecht Berkessel, Ralf Lach, Wolfgang Grellmann i Rameshwar Adhikari. "Synthesis and Characterization of Nanostructured Blends of Epoxy Resin and Block Copolymers". Nepal Journal of Science and Technology 13, nr 1 (21.01.2013): 81–88. http://dx.doi.org/10.3126/njst.v13i1.7445.
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Polystyrene–polybutadiene block copolymers having different molecular architectures were epoxidized by using meta-chloroperoxybenzoic acid (MCPBA). Then, the blends with epoxy resin (diglycidyl ether of bisphenol-A; DGEBA) and their nanocomposites with boehmite and layered silicate nanofiller in presence of methylene dianiline (MDA) as a hardener were prepared. The epoxidized copolymers and the composites were characterized by Fourier transform infrared (FTIR) spectroscopy and microindentation technique. In this way, it was possible to tune the morphology of the nanostructured blends of the epoxy resin using the functionalized block copolymer as the template. The presence of nanostructured morphology was attested by the optical transparency of the blends as well as of the composites with nanofiller. The microhardness properties were improved by the incorporation of the nanoparticles, viz. boehmite and layered silicate. Nepal Journal of Science and Technology Vol. 13, No. 1 (2012) 81-88 DOI: http://dx.doi.org/10.3126/njst.v13i1.7445
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Liu, Jingwei, Yunsheng Ye, Xiaolin Xie i Xingping Zhou. "Effect of MWNT Functionalization with Tunable-Length Block Copolymers on Dispersity of MWNTs and Mechanical Properties of Epoxy/MWNT Composites". Polymers 14, nr 15 (1.08.2022): 3137. http://dx.doi.org/10.3390/polym14153137.
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The dispersion level of carbon nanotubes (CNTs) and interface design are two of the most crucial roles in developing the superior mechanical performance of polymer/CNT nanocomposites. In this work, a series of azide-terminated poly(glycidyl methacrylate)-block-poly(hexyl methacrylate) (PGMA-b-PHMA) copolymers with different PHMA chain lengths and similar PGMA chain lengths were grafted on the surface of multiwall carbon nanotubes (MWNTs). PHMA length changes significantly impact the grafting density and solubility in organic solvents of as-prepared block copolymer functionalized MWNTs(bc@fMWNTs). Then, the bc@fMWNTs were introduced to epoxy, and the resulted epoxy/bc@fMWNT composites show better mechanical properties than neat epoxy and epoxy/p-MWNT composites. The results suggest that longer PHMA chains cause the two competitive and opposing effects on the dispersion state and soft interface. On the one hand, the longer PHMA chains on the surface of MWNTs would afford higher deformation for the matrix and enhanced mobility for MWNTs because of the soft and flexible nature of PHMA, enhancing the energy dissipation during strain. On the other hand, as the length of PHMA extends, the dispersion level of bc@fMWNTs in epoxy declines, which is harmful to the composite’s mechanical properties. Hence, epoxy/bc@fMWNTs composites with relatively short PHMA chains show the best tensile and fracture properties.
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Gong, Yongji, Weihua Song, Yifan Wu, Daohai Zhang, Yufei Liu, Qian Zhao, Min He i Xiaolang Chen. "Effect of chain segment length on crystallization behaviors of poly(l-lactide-b-ethylene glycol-b-l-lactide) triblock copolymer". Polymers and Polymer Composites 28, nr 2 (22.07.2019): 77–88. http://dx.doi.org/10.1177/0967391119863951.
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The poly(l-lactide-b-ethylene glycol-b-l-lactide) (PLLA-PEG-PLLA) triblock copolymers with different chain segment length are fabricated by ring-opening polymerization. The structure, molecular weight, and crystallization behaviors of the triblock copolymers are characterized by Fourier transform infrared, nuclear magnetic resonance spectroscopy, gel permeation in chromatography, X-ray diffraction, differential scanning calorimetry, and polarizing optical microscopy (POM). The results show that the increase of block length is beneficial to improve its crystallization. In addition, the triblock copolymer exhibits a double crystallization phenomenon. The POM results indicate that PEG and PLLA chains of the copolymer crystallize in their respective crystallization temperature regions. The growth rate of the PLLA spherocrystal decreases and the dendritic spherocrystals appear with increasing the PEG chain length when the PLLA chain of the copolymer is isothermal crystallized at 80°C and PLLA chain length is constant. The growth rate of the PEG spherocrystal decreases and the spherocrystal morphology changes little with increasing PLLA chain length when the PEG chain is isothermal crystallized at 25°C and the length of PEG chain remained unchanged.
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Bowen, Rafael L., i William A. Marjenhoff. "Dental Composites/Glass Ionomers: the Materials". Advances in Dental Research 6, nr 1 (wrzesień 1992): 44–49. http://dx.doi.org/10.1177/08959374920060011601.
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Most commercial dental composites contain liquid dimethacrylate monomers (including BIS-GMA or variations of it) and silica-containing compositions as inorganic reinforcing filler particles coated with methacrylate-functional silane coupling agents to bond the resin to the filler. They also contain initiators, accelerators, photo-initiators, photosensitizers, polymerization inhibitors, and UV absorbers. Durability is a major problem with posterior composites. The typical life-span of posterior composites is from three to 10 years, with large fillings usually fewer than five years. Polymerization shrinkage and inadequate adhesion to cavity walls are remaining problems. Some pulp irritation can occur if deep restorations are not placed over a protective film. Some have advocated the use of glass-ionomer cement as a lining under resin composite restorations in dentin. The concept of glass-ionomer cements (GICs) was introduced to the dental profession in the early 1970's. Current GICs may contain poly(acrylic acid) or a copolymer. Higher-molecular-weight copolymers may also be used to improve the physical properties of some GICs. Stronger and less-brittle hybrid materials have been produced by the addition of watersoluble compatible polymers to form light-curing GIC formulations. The ion-leachable aluminosilicate glass powder, in an aqueous solution of a polymer or copolymer of acrylic acid, is attacked by the hydrated protons of the acid, causing the release of aluminum and calcium ions. Salt bridges are formed, and a gel matrix surrounds the unreacted glass particles. The matrix is adhesive to mineralized tissues. Provisions must be made for maintenance of the water balance of restorations for the first 24 hours. A varnish to seal newly-placed restorations is provided by most manufacturers. The introduction of metal powder to GICs significantly improved abrasion resistance.
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Patel, Rakesh B., Umesh P. Tarpada i Dipak K. Raval. "A study on glass fiber reinforced composites from 2,3-epoxypropyl-3-(2-furyl) acrylate and methyl methacrylate". Journal of Polymer Engineering 34, nr 6 (1.08.2014): 531–41. http://dx.doi.org/10.1515/polyeng-2013-0084.
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Abstract 2,3-Epoxypropyl-3-(2-furyl) acrylate (EPFA) was synthesized from 3-(2-furyl) acrylic acid (FAA) and epichlorohydrin, followed by copolymerization of EPFA with methyl methacrylate (MMA) by varying the mole ratio of EPFA:MMA at different reaction times using benzoyl peroxide as an initiator at 80°C in toluene. The FAA, EPFA and copolymers were characterized by Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (1H NMR) spectroscopy, viscosity measurement, gel permeation chromatography (GPC) as well as epoxy equivalent weight (EEW). Mechanical properties, electrical properties and chemical resistance of the selected glass fiber reinforced composites were determined according to the ASTM method and discussed in light of copolymer composites.
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Mohapatra, Ranjit, Ashok K. Swain, Roomky Mohapatra, Pradeep K. Rana i Prafulla K. Sahoo. "Poly(2-Hydroxy Ethyl Methacrylate-co-Acrylic Acid) as Novel Biodegradable Macroporous Hydrogel". Polymers and Polymer Composites 13, nr 8 (listopad 2005): 807–14. http://dx.doi.org/10.1177/096739110501300806.
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Hydrogels of macroporous copolymer, 2-hydroxyl ethyl methacrylate with acrylic acid, were prepared in the presence of N,N'-methylene-bis-acrylamide as crosslinker and benzoyl peroxide as initiator. The structure of the copolymer was characterized by FT-IR, H1-NMR and scanning electron microscopy and the thermal stability by thermogravimetric analysis. Its hydrogel character was observed by studying the swelling of the copolymers simply by measuring weight gain and weight loss. The swelling was determined in distilled water, saline solution and buffers of pH, 4 and 9.2, was found to increase with increasing pH, attaining a maximum at pH 9.2. The biodegradability of the copolymers was studied by introducing microbes to the culture media along with the prepared sample and it was verified by examining the surface morphology by SEM. The rate of biodegradation was monitored by the CO2 release method.