Статті в журналах: "Functional copolymers"

1

Kalinova, Radostina, Miroslava Valchanova, Ivaylo Dimitrov, Sevdalina Turmanova, Iva Ugrinova, Maria Petrova, Zlatina Vlahova, and Stanislav Rangelov. "Functional Polyglycidol-Based Block Copolymers for DNA Complexation." International Journal of Molecular Sciences 22, no. 17 (September 4, 2021): 9606. http://dx.doi.org/10.3390/ijms22179606.

Повний текст джерела

Анотація:

Gene therapy is an attractive therapeutic method for the treatment of genetic disorders for which the efficient delivery of nucleic acids into a target cell is critical. The present study is aimed at evaluating the potential of copolymers based on linear polyglycidol to act as carriers of nucleic acids. Functional copolymers with linear polyglycidol as a non-ionic hydrophilic block and a second block bearing amine hydrochloride pendant groups were prepared using previously synthesized poly(allyl glycidyl ether)-b-polyglycidol block copolymers as precursors. The amine functionalities were introduced via highly efficient radical addition of 2-aminoethanethiol hydrochloride to the alkene side groups. The modified copolymers formed loose aggregates with strongly positive surface charge in aqueous media, stabilized by the presence of dodecyl residues at the end of the copolymer structures and the hydrogen-bonding interactions in polyglycidol segments. The copolymer aggregates were able to condense DNA into stable and compact nanosized polyplex particles through electrostatic interactions. The copolymers and the corresponding polyplexes showed low to moderate cytotoxicity on a panel of human cancer cell lines. The cell internalization evaluation demonstrated the capability of the polyplexes to successfully deliver DNA into the cancer cells.

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Wan, Fei, Rui Pu, and Chao Feng. "Ultralow Fouling Surfaces from Self-Assembly of Copolymers with Sticky Biomimic Functional Groups." Key Engineering Materials 775 (August 2018): 298–304. http://dx.doi.org/10.4028/www.scientific.net/kem.775.298.

Повний текст джерела

Анотація:

In this work, a new strategy for preparing antifouling surfaces by a simple dip-coating procedure is reported. Copolymers containing catechol and antifouling pendant side groups were synthesized via the free radical polymerization of a catechol-containing methacrylate monomer N-(3,4-dihydroxyphenyl) ethyl methacrylamide and three kinds of antifouling monomers separately using α,α’-azobisisobutyronitrile (AIBN) as initiator. These copolymers can assemble onto variety of materials surfaces including metals, oxides, and polymers such as PTFE using catechol groups via multivalent complex bonding. The catechol groups are helpful for adhesion of the copolymers onto the surfaces, while the other side chains endow the coatings with antifouling activity. Modification on the substrates with copolymers were verified by X-ray photoelectron spectroscopy (XPS), the images of microalgaes and zoospores setting on the substrates were taken by microscope and scanning electron microscope (SEM). The copolymer-coated surfaces, especially the surface modified by copolymer with 3-sulfopropyl methacrylate potassium salt (SPMA(K)), displayed excellent antifouling activity and fouling-release properties in settlement assay with microalgaes and zoospores.

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Lipowska-Kur, Daria, Łukasz Otulakowski, Barbara Trzebicka, Alicja Utrata-Wesołek, and Andrzej Dworak. "Thermoresponsive Nanogels of Modified Poly((di(ethylene glycol) methyl ether methacrylate)-co-(2-aminoethyl methacrylate))s." Polymers 12, no. 8 (July 24, 2020): 1645. http://dx.doi.org/10.3390/polym12081645.

Повний текст джерела

Анотація:

A series of copolymers of di(ethylene glycol) methyl ether methacrylate (D) and 2-aminoethyl methacrylate (A) (P(D-co-A)) with variable ratios of comonomers were synthesized using atom transfer radical polymerization. Then, the amino groups of obtained copolymers were modified to clickable azide or prop-2-yn-1-yl carbamate groups. A thermoresponsive copolymers were obtained with the value of cloud point temperature (TCP) dependent on the type and number of functional groups in the copolymer and on the concentration of solutions. For P(D-co-A) copolymers, the TCP increased with increasing content of 2-aminoethyl methacrylate comonomer. The presence of azide and prop-2-yn-1-yl carbamate groups caused the changes of TCP of modified copolymers. All studied copolymers in dilute aqueous solutions aggregated above TCP to nanoparticles with sizes dependent on the solution concentration, heating procedures, and types and numbers of functional groups present in a copolymer chain. The presence of hydrophilic elements in the chain and the increase in the copolymer concentration led to the enlargement of the particle sizes. Aggregates were crosslinked using click reaction between an azide and prop-2-yn-1-yl carbamate groups that led to stable thermoresponsive nanogels. A systematic study of the behavior of copolymers allowed the determination of the chains useful for possible application in drug delivery.

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Benavides, R., L. W. Oenning, M. M. S. Paula, L. Da Silva, and C. Kotzian. "Use of a TrI-functional Crosslinking Agent in Styrene/Acrylic Acid Copolymers to Enhance Mechanical Properties for use as Membranes in Fuel Cells." Journal of New Materials for Electrochemical Systems 16, no. 3 (July 4, 2013): 157–62. http://dx.doi.org/10.14447/jnmes.v16i3.5.

Повний текст джерела

Анотація:

Alternative copolymers to the well-known Nafion membranes are the styrene/acrylic acid PS/AA) copolymers, which have advantages in cost and availability of raw materials. Previous attempts to improve their mechanical properties involved crosslinking with divinyl benzene, but in this case the use of the tri-functional monomer TMPTMA (trimethylol propane trimethacrylate) is examined. Copolymers with a PS/AA molar ratio of 94/6 were prepared by a free radical polymerization reaction, including TMPTMA at 0.1, 0.01 and 0.001 % mol concentrations. Reactions were followed by percentage yield (gravimetry), Infrared spectroscopy (FTIR) and extent of crosslinking by gel percentage evaluation (soxhlet extraction) with three different solvents (water, tetrahydrofuran and dichloromethane). Thermal transitions were followed by calorimetry (DSC), stability by thermogravimetry (TGA) and mechanical properties by dynamic mechanical analysis (DMA). FTIR spectra show typical bands from the copolymer while the corresponding bands associated with crosslinking are overlapped; however, gel percentage evaluations show a higher level of crosslinking for the 0.1% TMPTMA copolymer and lack of solubility in water. DSC thermograms indicate an increment in the glass transition (Tg) and TGA exhibits a small increment in thermal stability for the crosslinked copolymers. Elastic moduli suggests a rubbery material for TMPTMA crosslinked copolymers while loss modulus confirms a Tg enhancement as observed by DSC. A 0.1 % TMPTMA copolymer does not form a membrane due to its insolubility and infusibility.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Jiang, Kai, Weiquan Xu, and Pingwen Zhang. "Analytic Structure of the SCFT Energy Functional of Multicomponent Block Copolymers." Communications in Computational Physics 17, no. 5 (May 2015): 1360–87. http://dx.doi.org/10.4208/cicp.281113.271114a.

Повний текст джерела

Анотація:

AbstractThis paper concerns the analytic structure of the self-consistent field theory (SCFT) energy functional of multicomponent block copolymer systems which contain more than two chemically distinct blocks. The SCFT has enjoyed considered success and wide usage in investigation of the complex phase behavior of block copolymers. It is well-known that the physical solutions of the SCFT equations are saddle points, however, the analytic structure of the SCFT energy functional has received little attention over the years. A recent work by Fredrickson and collaborators [see the monograph by Fredrickson,The Equilibrium Theory of Inhomogeneous Polymers, (2006), pp. 203–209] has analysed the mathematical structure of the field energy functional for polymeric systems, and clarified the index-1 saddle point nature of the problem caused by the incompressible constraint. In this paper, our goals are to draw further attention to multicomponent block copolymers utilizing the Hubbard-Stratonovich transformation used by Fredrickson and co-workers. We firstly show that the saddle point character of the SCFT energy functional of multicomponent block copolymer systems may be high index, not only produced by the incompressible constraint, but also by the Flory-Huggins interaction parameters. Our analysis will be beneficial to many theoretical studies, such as the nucleation theory of ordered phases, the mesoscopic dynamics. As an application, we utilize the discovery to develop the gradient-based iterative schemes to solve the SCFT equations, and illustrate its performance through several numerical experiments takingABCstar triblock copolymers as an example.

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Börner, Hans G., and Helmut Schlaad. "Bioinspired functional block copolymers." Soft Matter 3, no. 4 (2007): 394–408. http://dx.doi.org/10.1039/b615985k.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Jamshidi, H., and A. Rabiee. "Synthesis and Characterization of Acrylamide-Based Anionic Copolymer and Investigation of Solution Properties." Advances in Materials Science and Engineering 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/728675.

Повний текст джерела

Анотація:

The copolymer of acrylamide (AM) and 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) was synthesized through radical solution polymerization by potassium persulfate as initiator. By changing the AMPS feed ratio from 10 to 70%, and keeping other reaction conditions constant, different copolymers were synthesized. The techniques of Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H-13C-NMR) spectroscopy were used for identification of functional groups and confirmation of copolymers’ structure. Intrinsic and apparent viscosity of samples were measured in aqueous sodium chloride solution under standard conditions. The anionic degree of copolymers was determined by back titration method and by13C-NMR spectroscopy. Molecular weight of copolymers was determined by the Mark-Houwink relationship. The measured molecular weight of samples showed that we have acquired a high molecular weight product. The effect of different range of shear rates on solution viscosity was evaluated. The copolymer solutions showed non-Newtonian shear thinning behavior. The performance of copolymers with respect to shear resistance and molecular weight was evaluated from industry application standpoint.

Стилі APA, Harvard, Vancouver, ISO та ін.

8

You, Qian Qian, and Pu Yu Zhang. "Synthesis of Polystyrene-B-Poly(Ethylene Oxide)monomethyl Ethermethacrylate Block Copolymers and its Self-Assembly in Aqueous Solution." Advanced Materials Research 284-286 (July 2011): 769–72. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.769.

Повний текст джерела

Анотація:

The block copolymer of PSt-b-POEOMA with the end of -COOH functional group has been synthesized by reversible addition fragmentation chain-transfer (RAFT) using S,S′-Bis(α,α′-dimethyl-α′′-acetic acid)-trithiocarbonate (BDATC) as a chain transfer agent. The architectures of the copolymers were confirmed by FT-IR and 1HNMR spectra. GPC analysis was used to estimate the molecular weight and the molecular weight distribution of the copolymers. Meanwhile, The nanostructures of the block copolymers PSt-b-POEOMA micelles formed in aqueous solution were observed by transmission electron microscopy (TEM) and dynamic light scattering (DLS).

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Fan, Yu Jiang, Jie Liang, Guo Ping Chen, Tetsuya Tateishi, Zhong Wei Gu та Xing Dong Zhang. "Star-Shaped Poly (Γ-Caprolactone-b-Ethylene Glycol): Synthesis, Characterization and Aggregation Behavior". Key Engineering Materials 342-343 (липень 2007): 725–28. http://dx.doi.org/10.4028/www.scientific.net/kem.342-343.725.

Повний текст джерела

Анотація:

Linear and Star-shaped PCL-b-PEG copolymers were synthesized through a two step process, including the first step to synthesize the star-shaped PCL through ring-opening polymerization of Γ-caprolactone initiated from multi-functional alcohol under the existence of tin(II) ethylhexanoate [Sn(Oct)2] catalyst, and the following step to couple the obtained star-shaped PCL with PEG segments using bi-functional linker. The structure of the polymers was confirmed by IR, NMR, GPC, et al. The aggregation behaviors of the star-shape copolymers were compared with that of the linear block copolymer with corresponding molecular weight of each arm, and the influences of structure factors were discussed.

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Peng, Xiao Quan, and Chun Ju He. "Functional Chain Transfer Agent and its Application in Block Polymer Synthesis." Applied Mechanics and Materials 799-800 (October 2015): 475–78. http://dx.doi.org/10.4028/www.scientific.net/amm.799-800.475.

Повний текст джерела

Анотація:

In this report, s-1-dodecyl-s’-(α,α’-dimethyl-α’’-dimethyl-α’’-aceticacid) trithiocarbonate (RAFT-COOH) was successfully synthesized by phase transfer catalyst reaction, which was then amidated with diaminopropyl terminated polydimethylsiloxane (NH2-PDMS-NH2) to synthesize PDMS-based macro-RAFT agent to control the synthesis of tri-block copolymer PDMA-b-PDMS-b-PDMA. The successful synthesis of small and macro chain transfer has been confirmed by techniques of FTIR. Moreover, the polymerization to synthesize tri-block copolymer proceeded with first-order kinetics, which showed the reaction system was a controlled/‘living’ polymerization. The triblock copolymers have also been characterized by FTIR, 1HNMR, and GPC techniques, which confirmed the successful synthesis of triblock copolymer.

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Hussain, Hazrat, Elkin Amado, and Jörg Kressler. "Functional Polyether-based Amphiphilic Block Copolymers Synthesized by Atom-transfer Radical Polymerization." Australian Journal of Chemistry 64, no. 9 (2011): 1183. http://dx.doi.org/10.1071/ch11147.

Повний текст джерела

Анотація:

This review deals with the synthesis, physical properties, and applications of amphiphilic block copolymers based on hydrophilic poly(ethylene oxide) (PEO) or hydrophobic poly(propylene oxide) (PPO). Oligomeric PEO and PPO are frequently functionalized by converting their OH end groups into macroinitiators for atom-transfer radical polymerization. They are then used to generate additional blocks as part of complex copolymer architectures. Adding hydrophobic and hydrophilic blocks, respectively, leads to polymers with amphiphilic character in water. They are surface active and form micelles above a critical micellization concentration. Together with recent developments in post-polymerization techniques through quantitative coupling reactions (‘click’ chemistry) a broad variety of tailored functionalities can be introduced to the amphiphilic block copolymers. Examples are outlined including stimuli responsiveness, membrane penetrating ability, formation of multi-compartmentalized micelles, etc.

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Waware, Umesh S., and Mohd Rashid. "Synthesis and characterization of electrically conducting copolymers of poly(aniline-co-o-iodoaniline)." Functional Materials Letters 07, no. 05 (August 26, 2014): 1450062. http://dx.doi.org/10.1142/s1793604714500623.

Повний текст джерела

Анотація:

Functionalized copolymers of poly(aniline-co-o-iodoaniline) have been synthesized by the chemical oxidative polymerization method by using o-iodoaniline (o-IA) and aniline (AN) as monomer units by changing their molar feed ratio in acid aqueous medium. The physical properties viz; solubility, electrical conductivity have been studied to characterize them. The copolymers possess better solubility than unsubstituted homopolymer in organic solvent such as N -methyl-2-pyrrodinone (NMP). The conductivity of the pressed pellets of as-synthesized copolymers depends upon the content of o-IA in the polyaniline (PANI). The structural confirmation of the copolymer has been explained by Fourier transform infrared spectroscopy study which suggest that AN and o-IA units are uniformly distributed along the polymer chain and thus, the physical properties of copolymers may possibly be tailored by varying the molar feed ratio in copolymerization reactions. The conductivity of the copolymer decreases upon increasing the o-IA content in molar feed, because the introduction of –I- as a functional group reduces the extent of conjugation of the polymer chain.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Nemțanu, Monica R., Mirela Brașoveanu, Elena Pincu, and Viorica Meltzer. "Water-Soluble Starch-Based Copolymers Synthesized by Electron Beam Irradiation: Physicochemical and Functional Characterization." Materials 15, no. 3 (January 29, 2022): 1061. http://dx.doi.org/10.3390/ma15031061.

Повний текст джерела

Анотація:

Modification of natural polymers for applications in the treatment of waste and surface waters is a continuous concern of researchers and technologists in close relation to the advantages they provide as related to classical polymeric flocculants. In this work, copolymers of starch-graft-polyacrylamide (St-g-PAM) were synthesized by electron beam irradiation used as the free radical initiator by applying different irradiation doses and dose rates. St-g-PAM loaded with ex situ prepared silver nanoparticles was also synthesized by using an accelerated electron beam. The graft copolymers were characterized by chemical analysis, rheology, and differential scanning calorimetry (DSC). The results showed that the level of grafting (monomer conversion coefficient and residual monomer concentration), intrinsic viscosity and thermal behavior (thermodynamic parameters) were influenced by the irradiation dose, dose rate and presence of silver nanoparticles. The flocculation performances of the synthesized copolymers were also tested on water from the meat industry in experiments at the laboratory level. In the coagulation–flocculation process, the copolymer aqueous solutions showed good efficiency to improve different water quality indicators.

Стилі APA, Harvard, Vancouver, ISO та ін.

14

CATIKER, Efkan, Temel OZTURK, Bedrettin SAVAS, Mehmet ATAKAY та Bekir SALIH. "Synthesis of Novel Aba-Type Amphiphilic Copolymers Including 2-Hydroxypropyl Propionate and N-Isobutoxymethyl Β-Alanine by Peg-Dialkoxide Initiated Hydrogen-Transfer Polymerization". Eurasia Proceedings of Science Technology Engineering and Mathematics 15 (31 грудня 2021): 21–27. http://dx.doi.org/10.55549/epstem.1052148.

Повний текст джерела

Анотація:

Novel ABA-type amphiphilic copolymers were prepared using end-groups activated poly (ethylene glycol) (PEG) as an initiator of hydrogen-transfer polymerization (HTP). For this purpose, PEG with 1450 Da (PEG-1450) was treated with the equivalent amount of sodium hydride to synthesize PEG with dialkoxide end-groups, namely PEG-dialkoxide. Using the PEG-dialkoxide as a macroinitiator, base-catalysed HTP of 2-hydroxypropyl acrylate (HPA), and N-isobutoxymethyl acrylamide (BMA) were performed to achieve the novel ABA-type block copolymers. The copolymers were obtained with relatively high yields. Characterization of the ABA-type amphiphilic copolymers was carried out using FTIR and MALDI mass spectrometry. FTIR spectra of the copolymers exhibited some characteristic bands assigning to the functional groups arising from the mechanism of HTP. Molar mass distributions of the copolymers from the MALDI mass study pointed out that chain extensions by mass in each copolymer were almost equal. Hence, the MALDI mass spectra of the copolymers revealed that chain extensions of PEGs by HPA, and BMA units were successfully fulfilled.

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Grochowicz, Marta, Łukasz Szajnecki, and Magdalena Rogulska. "Crosslinked 4-Vinylpyridine Monodisperse Functional Microspheres for Sorption of Ibuprofen and Ketoprofen." Polymers 14, no. 10 (May 20, 2022): 2080. http://dx.doi.org/10.3390/polym14102080.

Повний текст джерела

Анотація:

Nowadays, ibuprofen and ketoprofen are widely used over-the-counter medications to treat inflammation, fever, or pain. Their high consumption and improper disposal cause them to get into the environment and often pollute surface water. In this study, the new polymeric porous microspheres based on 4-vinylpyridine (4VP) are presented as effective sorbents for ibuprofen and ketoprofen preconcentration and removal. The porous microspheres were obtained via seed swelling polymerization with the use of two types of methacrylate crosslinkers, i.e., trimethylolpropane trimethacrylate (TRIM) and 1,4-dimethacryloiloxybenzene (14DMB). Additionally, as a reference sorbent, a copolymer of styrene and divinylbenzene was obtained. Porous structure investigations showed that the microspheres possess a specific surface area of about 100 m2/g, but noticeable differences were observed in their internal topography depending on the type of crosslinker used. Moreover, the porous structure of dry and swollen microspheres differs significantly. Swollen copolymers reveal the presence of micropores. The 4VP microspheres are characterized by high thermal stability; their initial decomposition temperature is about 300 °C. The performance of the 4VP copolymers as sorbents in aqueous solutions of drugs was evaluated in static and dynamic modes at three pH values of 3, 7, and 11. The highest sorption efficiency was obtained for ibuprofen and ketoprofen in pH 3. Both 4VP copolymers indicate the high sorption capacity in a static sorption as follows: towards ketoprofen of about 40 mg/g whereas towards ibuprofen of about 90 mg/g and 75 mg/g on copolymer crosslinked with trimethylolpropane trimethacrylate and 1,4-dimethacryloiloxybenzene, respectively. The recovery of ibuprofen and ketoprofen after dynamic sorption experiments was higher than 90%.

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Kumar Sharma, Bhoopesh, Megha Walia, Archana Chaudhary, Yogesh Sharma, and Shaile Thakur. "Synthesis of An Amidoximated Acrylic Copolymer Membrane (AACM) Treated with Nano Silver Particles to Study the Antibacterial Efficiency of The Membrane." IOP Conference Series: Materials Science and Engineering 1224, no. 1 (January 1, 2022): 012020. http://dx.doi.org/10.1088/1757-899x/1224/1/012020.

Повний текст джерела

Анотація:

Abstract Abstract Polymers with cationic functional groups are proven to be an effective antimicrobial barrier. Particles, organic debris, and microbes can be well removed from drinking water using polymer membrane filtration. A variety of copolymers are utilized in the synthesis of such membranes. In this study, a copolymer membrane was synthesized first, and then Amidoximation was used to convert a portion of the copolymer’s nitrile groups to amidoxime groups. The membrane was treated with HA at 60-80°C in an aqueous solution to obtain an Amidoximated film. After being treated with Nano Silver particles, the efficiency of the prefabricated and particularly produced copolymer film as an antibacterial water disinfectant was analyzed. Various techniques were used to analyse the virgin and Amidoximated Acrylic Copolymer Membranes (AACM), including X-ray diffraction (EDX), Fourier Transform Infrared (FTIR), Scanning Electron Microscope, Transmission Electron Microscope, and Thermogravimetric analysis, Many substantial changes in the copolymer characteristics, including functionality, crystallinity, thermal activity, hydrophilicity, elemental composition, surface morphology, and antibacterial activity, were identified during the Amidoximation phase. It was revealed that an Amidoximated copolymer membrane outperforms an untreated membrane in terms of antibacterial activity.

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Shih, Ting-Yu, Jean-Dean Yang, Yu-Hua Chen, Chia-Wei Hong, Mei-Ju Yang, and Jui-Hsiang Chen. "DEVELOPMENT OF PEG-CONTAINING BRUSH COPOLYMER: THEIR EFFECT ON RESISTANCE TO PROTEIN ADSORPTION BEHAVIORS." Biomedical Engineering: Applications, Basis and Communications 25, no. 05 (October 2013): 1340008. http://dx.doi.org/10.4015/s1016237213400085.

Повний текст джерела

Анотація:

Polyethylene glycol (PEG) has been grafted onto surface of many medical devices to reduce or eliminate protein adsorption that often leads to infection or inflammatory responses. Besides commonly used surface activation strategies, here in this work, the novel functional brush copolymer poly (vinyl alcohol)-g-PEG-co-polyurethane (PVA-g-(PEG-co-PU)) was first synthesized, characterized, and evaluated. PVA is used here as a versatile backbone platform for grafting functional molecules. On the one hand, the PU molecules can attach to the surface of desired PU-based implants, on the other hand, the presence of densely grafted PEG at the materials–tissue interface effectively impedes nonspecific protein adsorption. These copolymers with various grafting ratio of PEG and PU were analyzed by Fourier transform infrared spectroscopy and gel permeation chromatography. The brush copolymers that were obtained were further coated on the PU surface and contact angle measurements were performed. It was found that the brush copolymers turn the surface more hydrophilic with increasing PEG grafting density. Furthermore, the effects of PEG ratio on protein adsorption-resistant behavior were investigated. Protein adsorption was found to be the lowest on the surfaces with the highest PEG grafting density on PVA backbone. The study demonstrated unique brush copolymer to work as a potentially useful coating material.

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Prozorova, G. F., T. G. Ermakova, N. P. Kuznetsova, S. A. Korzhova, and A. I. Emel’yanov. "NEW HEAT-RESISTANT FUNCTIONAL COPOLYMERS." PROCEEDINGS OF UNIVERSITIES APPLIED CHEMISTRY AND BIOTECHNOLOGY 8, no. 4 (2018): 192–96. http://dx.doi.org/10.21285/2227-2925-2018-8-4-192-196.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Prozorova, G. F., N. P. Kuznetsova, and S. A. Korzhova. "Chemical modification of functional copolymers." Proceedings of Universities. Applied Chemistry and Biotechnology 10, no. 1 (April 2, 2020): 169–73. http://dx.doi.org/10.21285/2227-2925-2020-10-1-169-173.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Liu, Guojun. "Nanostructures of functional block copolymers." Current Opinion in Colloid & Interface Science 3, no. 2 (April 1998): 200–208. http://dx.doi.org/10.1016/s1359-0294(98)80014-9.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Zhou, Jiawen, George R. Whittell, and Ian Manners. "Metalloblock Copolymers: New Functional Nanomaterials." Macromolecules 47, no. 11 (May 13, 2014): 3529–43. http://dx.doi.org/10.1021/ma500106x.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Fan, Xiaoguang, Liyan Wu, and Lei Yang. "Fabrication and characterization of thermoresponsive composite carriers: PNIPAAm-grafted glass spheres." e-Polymers 21, no. 1 (January 1, 2021): 222–33. http://dx.doi.org/10.1515/epoly-2021-0023.

Повний текст джерела

Анотація:

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.

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Erol, Fatime Eren, Deniz Sinirlioglu, Sedat Cosgun, and Ali Ekrem Muftuoglu. "Synthesis of Fluorinated Amphiphilic Block Copolymers Based on PEGMA, HEMA, and MMA via ATRP and CuAAC Click Chemistry." International Journal of Polymer Science 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/464806.

Повний текст джерела

Анотація:

Synthesis of fluorinated amphiphilic block copolymers via atom transfer radical polymerization (ATRP) and Cu(I) catalyzed Huisgen 1,3-dipolar cycloaddition (CuAAC) was demonstrated. First, a PEGMA and MMA based block copolymer carrying multiple side-chain acetylene moieties on the hydrophobic segment for postfunctionalization was carried out. This involves the synthesis of a series of P(HEMA-co-MMA) random copolymers to be employed as macroinitiators in the controlled synthesis of P(HEMA-co-MMA)-block-PPEGMA block copolymers by using ATRP, followed by a modification step on the hydroxyl side groups of HEMA via Steglich esterification to afford propargyl side-functional polymer, alkyne-P(HEMA-co-MMA)-block-PPEGMA. Finally, click coupling between side-chain acetylene functionalities and 2,3,4,5,6-pentafluorobenzyl azide yielded fluorinated amphiphilic block copolymers. The obtained polymers were structurally characterized by1H-NMR,19F-NMR, FT-IR, and GPC. Their thermal characterizations were performed using DSC and TGA.

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Ristic, Ivan, Ljubisa Nikolic, Vesna Nikolic, Jaroslava Budinski-Simendic, and Vladimir Zdravkovic. "The influence of monomer molar ratio on the properties of copolymers based on methyl methacrylate and methacrylic acid." Chemical Industry 63, no. 6 (2009): 611–19. http://dx.doi.org/10.2298/hemind0906611r.

Повний текст джерела

Анотація:

The application of polymers for controlled drug delivery is influenced by no toxicity and solubility in different pH mediums. There already are existing pharmaceutical medicaments based on aqueous dispersion of an anionic copolymer methyl acrylate, methyl methacrylate and methacrylic acid. The aim of this work was to synthesise copolymers of methyl methacrylate and methacrylic acid and to estimate the effects of monomers ratio (1:1 and 1:2) on the molecular mass, polydispersity index, and solubility of obtained polymers. Acetone was used as a solvent because both monomers and the initiator azobisisobutyronitrile are soluble in it. FTIR method was used for functional group characterization, the gel permeation chromatography method for average molecular weights and the distribution of molecular weights determinations. High pressure liquid chromatography (HPLC) was applied for the estimation of residual monomers in obtained copolymers. The titration with ethanol solution of NaOH was used for assessing of monomer units in copolymers. The copolymer with the molar ratio of monomers 1:1 was soluble in water bufer with pH values higher then 6, while the copolymer with the molar ratio of monomers 1:2 was soluble in bufer with pH higher then 9.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Casas-Soto, Carlos Rafael, Alain Salvador Conejo-Dávila, Velia Osuna, David Chávez-Flores, José Carlos Espinoza-Hicks, Sergio Gabriel Flores-Gallardo, and Alejandro Vega-Rios. "Dibutyl Itaconate and Lauryl Methacrylate Copolymers by Emulsion Polymerization for Development of Sustainable Pressure-Sensitive Adhesives." Polymers 14, no. 3 (February 7, 2022): 632. http://dx.doi.org/10.3390/polym14030632.

Повний текст джерела

Анотація:

Renewable polymers possess the potential to replace monomers from petrochemical sources. The design and development of polymeric materials from sustainable materials are a technological challenge. The main objectives of this study were to study the microstructure of copolymers based on itaconic acid (IA), di-n-butyl itaconate (DBI), and lauryl methacrylate (LMA); and to explore and to evaluate these copolymers as pressure-sensitive adhesives (PSA). The copolymer synthesis was carried out through batch emulsion radical polymerization, an environmentally friendly process. IA was used in a small fixed amount as a functional comonomer, and LMA was selected due to low glass transition temperature (Tg). The structure of synthesized copolymers was studied by FTIR, 1H-NMR, Soxhlet extraction, and molecular weight analyses by GPC. Furthermore, the viscoelastic and thermal properties of copolymer films were characterized by DMA, DSC, and TGA. The single Tg displayed by the poly(DBI-LMA-IA) terpolymers indicates that statistical random composition copolymers were obtained. Moreover, FTIR and NMR spectra confirm the chemical structure and composition. It was found that a cross-linked microstructure and higher molecular weight are observed with an increase of LMA in the feed led. The Tg and modulus (G′) of the copolymers film can be tuned with the ratio of DBI:LMA providing a platform for a wide range of applications as a biobased alternative to produce waterborne PSA.

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Cha, Sang Ho. "Preparation of Gold Nanocrystals Having Various Morphologies under Polymeric Bulk Phase." Applied Mechanics and Materials 548-549 (April 2014): 321–25. http://dx.doi.org/10.4028/www.scientific.net/amm.548-549.321.

Повний текст джерела

Анотація:

A novel synthetic approach for gold nanocrystals using triblock copolymer as a polymeric template was described. The triblock copolymer used in this study was poly (ethylene oxide)20-poly (propylene oxide)70-poly (ethylene oxide)20 with hydroxy or thiol end-functional groups. The complexes of HAuCl4 and triblock copolymers were prepared by mixing and drying. After exposed to the sunlight for a few days, the gold nanocrystals, which have different sizes and shapes according to the ripening time, end functional groups, and gold salt concentrations, were obtained. The optical properties of the gold nanocrystals were also discussed.

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Gringolts, Maria L., Yulia I. Denisova, Eugene Sh Finkelshtein, and Yaroslav V. Kudryavtsev. "Olefin metathesis in multiblock copolymer synthesis." Beilstein Journal of Organic Chemistry 15 (January 24, 2019): 218–35. http://dx.doi.org/10.3762/bjoc.15.21.

Повний текст джерела

Анотація:

Multiblock copolymers constitute a basis for an emerging class of nanomaterials that combine various functional properties with durability and enhanced mechanical characteristics. Our mini-review addresses synthetic approaches to the design of multiblock copolymers from unsaturated monomers and polymers using olefin metathesis reactions and other ways of chemical modification across double C=C bonds. The main techniques, actively developed during the last decade and discussed here, are the coupling of end-functionalized blocks, sequential ring-opening metathesis polymerization, and cross metathesis between unsaturated polymers, or macromolecular cross metathesis. The last topic attracts special interest due to its relative simplicity and broad opportunities to tailor the structure and hence the properties of the copolymer products. Whenever possible, we analyze the structure–property relations for multiblock copolymers and point to their possible practical applications.

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Rzayev, Zakir M. O., and Oktay Beşkardeş. "Boron-Containing Functional Copolymers for Bioengineering Applications." Collection of Czechoslovak Chemical Communications 72, no. 12 (2007): 1591–630. http://dx.doi.org/10.1135/cccc20071591.

Повний текст джерела

Анотація:

This review summarizes the some advances and results of our recent investigations, outlining the synthesis, structural phenomena, unique properties and application areas of boron-containing bioengineering copolymers. Particular attention is paid to the effects of hydrogen bonding in copolymerization reactions of boron-containing monomers, and in formation of supramacromolecular structures, bioconjugates, physically and chemically crosslinkable copolymers, and other important bioengineering materials.

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Wang, Ling, Zhendong Li, Pingsen Huang, and Wei Ding. "Synthesis of an Acrylamide Copolymer Containing Nano-SiO2 by Ex Situ Cu(0)-Mediated SET-LRP." International Journal of Polymer Science 2019 (January 27, 2019): 1–7. http://dx.doi.org/10.1155/2019/7379368.

Повний текст джерела

Анотація:

We report herein the synthesis of a novel star-shaped copolymer containing nano-SiO2 by single-electron transfer living radical polymerization (SET-LRP) in aqueous solution. The effects of polymerization conditions, such as the total amounts and molar ratios of the monomer, initiator, catalyst, ligand, and modified nano-SiO2, have been investigated through a series of experiments. The prepared acrylamide copolymers have been characterized by FTIR spectroscopy and 1H NMR spectrometry. The properties of the copolymers have been assessed by viscometry and rheometry. The results confirmed that the nano-SiO2 functional monomer was successfully combined in the SET-LRP. The optimum polymerization conditions were established through orthogonal experiments as a ratio of [AM] : [DMAEMA] : [I] : [CuBr] : [Me6TREN] of 674.4 : 35.5 : 1 : 1 : 2 at a total concentration of [AM] + [DMAEMA] of 2.5 mol/L. The appropriate concentration of the nano-SiO2 functional monomer (NSFM) was 0.5 wt% with respect to AM + DMAEMA. The rheology of the star-shaped copolymer exhibited a shear-thickening property when the shear rate exceeded a critical value (100 s−1). The AM/DMAEMA/NSFM copolymer displayed a higher viscosity than AM/DMAEMA at the same concentration. It was found that AM/DMAEMA/NSFM exhibited better salt and temperature tolerances.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Guzmán-Rabadán, Karla K., Marco A. Ramírez-Gómez, Marisol Güizado-Rodríguez, Jorge A. Guerrero-Álvarez, Víctor Barba, Miguel A. Basurto-Pensado, Rosario Galindo, Mario Rodríguez, and José L. Maldonado. "Synthesis and Physicochemical Characterization of New Polythiophenes Based on Three Different Monomers." MRS Proceedings 1767 (2015): 57–62. http://dx.doi.org/10.1557/opl.2015.227.

Повний текст джерела

Анотація:

ABSTRACTThe chemical synthesis of the copolymers poly(3-HT-co-EDOT-co-fluorene) and poly(3-HT-co-EDOT-co-TDR1) is reported. The first copolymer is derived of 3-hexylthiophene (3-HT), 3,4-ethylenedioxythiophene (EDOT) and 2,2'- (9,9-dioctyl-9H-fluorene-2,7-diyl) bisthiophene (fluorene). The second copolymer is derived of 3-hexylthiophene (3-HT), 3,4-ethylenedioxythiophene (EDOT) and (E)-2-(ethyl(4-((4-nitrophenyl)diazenyl)phenyl)amino)ethyl 2-(thiophen-3-yl)acetate (TDR1). Their physicochemical characterization by 1H NMR, FT-IR, DSC-TGA, GPC, UV-vis, cyclic voltammetry was carried out. These copolymers combine the high electron density and low oxidation potential of EDOT with the high charge mobility and processability of 3-HT. These are candidates for applications as active or barrier layer in electronic devices (bulk heterojuntion organic solar cells) or as functional membranes (e.g., sensors).

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Kai, Dan, Mein Jin Tan, Pei Lin Chee, Yun Khim Chua, Yong Liang Yap, and Xian Jun Loh. "Towards lignin-based functional materials in a sustainable world." Green Chemistry 18, no. 5 (2016): 1175–200. http://dx.doi.org/10.1039/c5gc02616d.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Dolgin, Ignat S., Pyotr P. Purygin та Yury P. Zarubin. "Measurement of volume resistivity in a series of copolymers of 4-methylstyrene-α-methylstyrene and 4-methoxystyrene-α-methylstyrene". Butlerov Communications 58, № 6 (30 червня 2019): 59–61. http://dx.doi.org/10.37952/roi-jbc-01/19-58-6-59.

Повний текст джерела

Анотація:

In the course of previous experiments, a technique was developed for the preparation of a copolymer of styrene and α-methylstyrene. This technique is an emulsion polymerization in the initiator of ammonium persulfate in an inert zone of direct current argon. It was found that the best emulsifier is potassium stearate. This substance can be explained by those copolymers that showed the best dielectric performance. In the course of the new experiment, a series of new copolymers of 4-methylstyrene-α-methylstyrene and 4-methoxystyrene-α-methyl-styrene was obtained in the molar ratios of the initial monomers of 8 : 3, 9 : 2 and 10 : 1 for both rows of copolymers. The outputs of the pure product for all compounds accounted for more than 60% in terms of the initial monomers. To further measure the value of the specific volume resistance of the material, films of each newly synthesized copolymer were obtained. Samples of the copolymers were dissolved in methylene chloride and applied to a smooth glass substrate. The choice of this solvent is due to its low toxicity and low boiling point. For the experiment were selected samples with a film thickness of 50 microns. Measurements of the specific volume resistance were carried out at the Research Institute "Girikond" (St. Petersburg) using an Agilent 4339B instrument. The operating voltage was 100 V. The measurement results showed that samples of 4-methoxystyrene-α-methylstyrene copolymer were several orders of magnitude superior to samples of 4-methylstyrene-α-methylstyrene copolymer. Most likely in this case such a difference in the indices of the specific volume resistance of the copolymer films is due to the nature of the functional groups of substituents in the copolymer. From the obtained measurement results it can be seen that the samples containing the methoxy group have a high resistance value compared to the samples containing a methyl group in their structure. In a series of samples of copolymer films, an increase in the specific volume resistivity index is observed with a decrease in the α-methylstyrene content in the copolymer structure. This dependence is observed for copolymers of 4-methylstyrene-α-methylstyrene and for 4-methoxystyrene-α-methylstyrene. The sample of 4-methoxystyrene-α-methylstyrene with a molar ratio of initial monomers of 10 : 1 has the highest value of specific volume resistance among all the obtained samples of copolymer films.

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Zhang, Xiaotong, Gen Li, Yuhao Chen, Keliang Wang, and Erlong Yang. "The Synthesis of Associative Copolymers with Both Amphoteric and Hydrophobic Groups and the Effect of the Degree of Association on the Instability of Emulsions." Polymers 13, no. 22 (November 22, 2021): 4041. http://dx.doi.org/10.3390/polym13224041.

Повний текст джерела

Анотація:

The acrylamide (AM)/methacryloyl ethyl sulfobetaine (SPE)/behenyl polyoxyethylene ether methacrylate (BEM) terpolymer (PASB) was synthesized by soap-free emulsion polymerization. Four types of PASBs were synthesized by adjusting the moles of AM and BEM with constant total moles of monomers. The synthesized copolymers were characterized by Fourier-transform infrared spectroscopy, thermogravimetry, molecular weight, and viscosity. By measuring the microscopic morphology and backscattered light intensity of the emulsions, the instability process of the emulsions prepared by PASBs was investigated in detail. The main instability processes of the emulsions prepared from PASBs within 45 min were flocculation and coalescence. The intermolecular association of copolymer PASBs was dominated by the behenyl functional groups on the molecular chains. The stability of the emulsions, which were prepared from isoviscosity aqueous solutions controlled by the concentration of the associative copolymers, was increased with the degree of association of copolymers. The hydrophobic association between the copolymer molecules can further slow down the flocculation and coalescence of the emulsion droplets on the basis of the same aqueous solution viscosity, which is one of the reasons for improving the stability of the emulsion.

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Epps, III, Thomas H., and Rachel K. O'Reilly. "Block copolymers: controlling nanostructure to generate functional materials – synthesis, characterization, and engineering." Chemical Science 7, no. 3 (2016): 1674–89. http://dx.doi.org/10.1039/c5sc03505h.

Повний текст джерела

Анотація:

In this perspective, we survey recent advances in the synthesis and characterization of block copolymers, discuss several key materials opportunities enabled by block copolymers, and highlight some of the challenges that currently limit further realization of block copolymers in promising nanoscale applications.

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Liu, Guojun. "Functional crosslinked nanostructures from block copolymers." Materials Science and Engineering: C 10, no. 1-2 (December 1999): 159–64. http://dx.doi.org/10.1016/s0928-4931(99)00114-9.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Hahn, Christian, Helmut Keul, and Martin Möller. "Graft Copolymers Based on Functional Polyesters." Macromolecular Symposia 296, no. 1 (October 2010): 366–70. http://dx.doi.org/10.1002/masy.201051050.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Justynska, Justyna, and Helmut Schlaad. "Modular Synthesis of Functional Block Copolymers." Macromolecular Rapid Communications 25, no. 16 (August 26, 2004): 1478–81. http://dx.doi.org/10.1002/marc.200400228.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Khokhlov, Alexei R., and Pavel G. Khalatur. "Biomimetic sequence design in functional copolymers." Current Opinion in Solid State and Materials Science 8, no. 1 (January 2004): 3–10. http://dx.doi.org/10.1016/j.cossms.2003.08.001.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Zhao, Guangkuo, Tongtong Ge, Yunfeng Yan, Qi Shuai, and Wei-Ke Su. "Highly Efficient Modular Construction of Functional Drug Delivery Platform Based on Amphiphilic Biodegradable Polymers via Click Chemistry." International Journal of Molecular Sciences 22, no. 19 (September 27, 2021): 10407. http://dx.doi.org/10.3390/ijms221910407.

Повний текст джерела

Анотація:

Amphiphilic copolymers with pendant functional groups in polyester segments are widely used in nanomedicine. These enriched functionalities are designed to form covalent conjugates with payloads or provide additional stabilization effects for encapsulated drugs. A general method is successfully developed for the efficient preparation of functional biodegradable PEG-polyester copolymers via click chemistry. Firstly, in the presence of mPEG as initiator, Sn(Oct)2-catalyzed ring-opening polymerization of the α-alkynyl functionalized lactone with D,L-lactide or ε-caprolactone afforded linear mPEG-polyesters bearing multiple pendant alkynyl groups. Kinetic studies indicated the formation of random copolymers. Through copper-catalyzed azide-alkyne cycloaddition reaction, various small azido molecules with different functionalities to polyester segments are efficiently grafted. The molecular weights, polydispersities and grafting efficiencies of azido molecules of these copolymers were investigated by NMR and GPC. Secondly, it is demonstrated that the resulting amphiphilic functional copolymers with low CMC values could self-assemble to form nanoparticles in aqueous media. In addition, the in vitro degradation study and cytotoxicity assays indicated the excellent biodegradability and low cytotoxicity of these copolymers. This work provides a general approach toward the preparation of functional PEG-polyester copolymers in a quite efficient way, which may further facilitate the application of functional PEG-polyesters as drug delivery materials.

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Niskanen, M., and T. I. Hukka. "Modeling of photoactive conjugated donor–acceptor copolymers: the effect of the exact HF exchange in DFT functionals on geometries and gap energies of oligomer and periodic models." Phys. Chem. Chem. Phys. 16, no. 26 (2014): 13294–305. http://dx.doi.org/10.1039/c4cp01165a.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Xiao, Jian, Zhicong Liu, Wangnian Zhang, Ning Deng, Jijun Liu, and Fulai Zhao. "Inverse Vulcanization of a Natural Monoene with Sulfur as Sustainable Electrochemically Active Materials for Lithium-Sulfur Batteries." Molecules 26, no. 22 (November 22, 2021): 7039. http://dx.doi.org/10.3390/molecules26227039.

Повний текст джерела

Анотація:

A novel soluble copolymer poly(S-MVT) was synthesized using a relatively quick one-pot solvent-free method, inverse vulcanization. Both of the two raw materials are sustainable, i.e., elemental sulfur is a by-product of the petroleum industry and 4-Methyl-5-vinylthiazole (MVT) is a natural monoene compound. The microstructure of poly(S-MVT) was characterized by FT-IR, 1H NMR, XPS spectroscopy, XRD, DSC SEM, and TEM. Test results indicated that the copolymers possess protonated thiazole nitrogen atoms, meso/macroporous structure, and solubility in tetrahydrofuran and chloroform. Moreover, the improved electronic properties of poly(S-MVT) relative to elemental sulfur have also been investigated by density functional theory (DFT) calculations. The copolymers are utilized successfully as the cathode active material in Li-S batteries. Upon employment, the copolymer with 15% MVT content provided good cycling stability at a capacity of ∼514 mA h g−1 (based on the mass of copolymer) and high Coulombic efficiencies (∼100%) over 100 cycles, as well as great rate performance.

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Misin, Vjacheslav, Nikolay Glagolev, and Michael Misin. "Polymers of Phenyldiacetylenes – Functional Thermostable Additions to Industrial Resins." Chemistry and Chemical Technology 4, no. 2 (June 15, 2010): 131–37. http://dx.doi.org/10.23939/chcht04.02.131.

Повний текст джерела

Анотація:

High thermal and thermooxidation stability of homo and copolymers of diphenyldiacetylene and p-diethynylbenzene was established. The amount of coke residue, obtained from commercial epoxy-resins, is essentially increased upon their modification with added polymers. Additions of polydiethynylbenzene to commercial olygoetheracrylates improved their thermooxidation stability.

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Levytskyy, Volodymyr, Ulyana Khromyak, and Oleh Suberlyak. "Sorption Properties of Materials Based on Polyvinylpyrrolidone Copolymers." Chemistry & Chemical Technology 4, no. 3 (September 15, 2010): 217–20. http://dx.doi.org/10.23939/chcht04.03.217.

Повний текст джерела

Анотація:

Sorption properties of polyvinylpyrrolidone copolymers regarding to different acid-base indicators, as well as heparin and iodine have been investigated. The amount of sorption active centers of synthesized copolymers depends upon synthesis conditions, namely upon temperature and initiator amount, and is determined by the nature of sorbates and copolymers functional groups.

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Beránek, Pavel, Paola Posocco, and Zbyšek Posel. "Phase Behavior of Gradient Copolymer Melts with Different Gradient Strengths Revealed by Mesoscale Simulations." Polymers 12, no. 11 (October 23, 2020): 2462. http://dx.doi.org/10.3390/polym12112462.

Повний текст джерела

Анотація:

Design and preparation of functional nanomaterials with specific properties requires precise control over their microscopic structure. A prototypical example is the self-assembly of diblock copolymers, which generate highly ordered structures controlled by three parameters: the chemical incompatibility between blocks, block size ratio and chain length. Recent advances in polymer synthesis have allowed for the preparation of gradient copolymers with controlled sequence chemistry, thus providing additional parameters to tailor their assembly. These are polydisperse monomer sequence, block size distribution and gradient strength. Here, we employ dissipative particle dynamics to describe the self-assembly of gradient copolymer melts with strong, intermediate, and weak gradient strength and compare their phase behavior to that of corresponding diblock copolymers. Gradient melts behave similarly when copolymers with a strong gradient are considered. Decreasing the gradient strength leads to the widening of the gyroid phase window, at the expense of cylindrical domains, and a remarkable extension of the lamellar phase. Finally, we show that weak gradient strength enhances chain packing in gyroid structures much more than in lamellar and cylindrical morphologies. Importantly, this work also provides a link between gradient copolymers morphology and parameters such as chemical incompatibility, chain length and monomer sequence as support for the rational design of these nanomaterials.

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Qiang, Na, Shuo Tang, Xiang Liao, Hao Liang, Fang Xie, and Ji-xiang Zhu. "Synthesis of Functional Polyester Based on Polylactic Acid and Its Effect on PC12 Cells after Coupling with Small Peptides." International Journal of Polymer Science 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/9829757.

Повний текст джерела

Анотація:

Polyesters containing functional groups are a suitable candidate matrix for cell culture in tissue engineering. Three types of semicrystalline copolymer poly(L-lactide-co-β-malic acid) [P(LA-co-BMD)] with pendent carboxyl groups were synthesized in this study. The functional monomer 3(S)-[(benzyloxycarbonyl)methyl]-1,4-dioxane-2,5-dione (BMD) was synthesized usingL-aspartic acid. The copolymer P(LA-co-BMD) was then synthesized through ring-opening copolymerization ofL-LA and BMD, with dodecanol as initiator and stannous octoate as catalyst. Copolymer structure was characterized by1H nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) analyses. Results of1H NMR and GPC analyses showed that the copolymers were synthesized successfully. DSC curves showed that the crystal melting peak and enthalpy decreased with increased BMD. The crystallinity of the copolymer was destroyed by the presence of the functional monomer. After deprotection, carboxyl groups were coupled with the isoleucine-lysine-valine-alanine-valine peptide throughN-hydroxysuccinimide/dicyclohexylcarbodiimide method. The small peptide was beneficial to the axon growth of PC12 cells.

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Prozorova, G. F., A. I. Emel’yanov, and S. A. Korzhova. "New functional copolymers of 1-vinyl-1,2,4-triazole with allylamine." Proceedings of Universities. Applied Chemistry and Biotechnology 10, no. 3 (October 8, 2020): 536–40. http://dx.doi.org/10.21285/2227-2925-2020-10-3-536-540.

Повний текст джерела

Анотація:

New water-soluble functional copolymers based on 1-vinyl-1,2,4-triazole and allylamine were synthesized under the action of free-radical initiation conditions and azobisisobutyric acid dinitrile. Сopolymers of various compositions with a molecular weight of 1287–30204 Da were obtained by varying reaction conditions. The structure, molecular weight and physicochemical properties of the copolymers were determined using elemental analysis, IR and NMR 1H-spectroscopy, gel permeation chromatography, potentiometric and turbidimetric titration, as well as dynamic light scattering and thermogravimetric analysis. It was established that the obtained copolymers, exhibiting the properties of high-resistance organic semiconductors, are characterized by a specific electrical conductivity of 10-13 – 10-14 S/cm and high resistance to thermal destruction (up to 260–280 °C). These copolymers are promising as stabilizing polymer matrices in the formation of biologically active water-soluble hybrid organic-inorganic nanocomposites.

Стилі APA, Harvard, Vancouver, ISO та ін.

47

Mushtaq, Shehla, Nasir M. Ahmad, Habib Nasir, Azhar Mahmood, and Hussnain A. Janjua. "Transpicuous-Cum-Fouling Resistant Copolymers of 3-Sulfopropyl Methacrylate and Methyl Methacrylate for Optronics Applications in Aquatic Medium and Healthcare." Advances in Polymer Technology 2020 (October 2, 2020): 1–11. http://dx.doi.org/10.1155/2020/5392074.

Повний текст джерела

Анотація:

The scope of optical sensors and scanners in aquatic media, fluids, and medical diagnostics has been limited by paucity of transparent shielding materials with antifouling potential. In this research endeavor, facile synthesis, characterization, and bioassay of antifouling transparent functional copolymers are reported. Copolymers of 3-sulfopropyl methacrylate (SPMA) and methyl methacrylate (MMA) were synthesized by free radical polymerization in various proportions. Samples PSM20, PSM30, PSM40, PSM50, and PSM60 contain 20%, 30%, 40%, 50%, and 60% SPMA by weight, respectively. Resultant products were characterized by FTIR and 1H-NMR spectroscopy. The synthesized copolymers have exhibited excellent transparency, i.e., 75% to 88%, as determined by the UV-Vis spectroscopic analysis. Transmittance was decreased from 6% to 2% in these copolymers upon changing the concentration of 3-sulfopropyl methacrylate from 20% to 50% owing to bacterial and algal biofilm formation. Water contact angle values were ranged from 18° to 63° and decreased with the increase in the polarity of copolymers. The surface energy lowest value 58 mJ/m2 and highest value 72 mJ/m2 were calculated for PSM20 and PSM50, respectively, by the Chibowski approach and Young equation. Sample PSM50 has exhibited the highest antibacterial activities, i.e., 18 mm and 19 mm, against Escherichia coli and Staphylococcus aureus, respectively, by the disk diffusion method. Copolymer PSM50 has shown minimum algal adhesion for Dictyosphaerium algae as observed by optical microscopy. This lower bacterial and algal adhesion is attributed to higher concentrations of anionic SPMA monomer that cause electrostatic repulsion between functional groups of the polymer and microorganisms. Thus, the resultant PSM50 product has exhibited good potential for optronics shielding application in aquatic medium and medical diagnostics.

Стилі APA, Harvard, Vancouver, ISO та ін.

48

Nedeljkovic, Dragutin. "Polystyrene-b-Poly(2-(Methoxyethoxy)ethyl Methacrylate) Polymerization by Different Controlled Polymerization Mechanisms." Polymers 13, no. 20 (October 12, 2021): 3505. http://dx.doi.org/10.3390/polym13203505.

Повний текст джерела

Анотація:

Functional polymers have been an important field of research in recent years. With the development of the controlled polymerization methods, block-copolymers of defined structures and properties could be obtained. In this paper, the possibility of the synthesis of the functional block-copolymer polystyrene-b-poly(2-(methoxyethoxy)ethyl methacrylate) was tested. The target was to prepare the polymer of the number average molecular weight (Mn) of approximately 120 that would contain 20–40% of poly(2-(methoxyethoxy)ethyl methacrylate) by mass and in which the polymer phases would be separated. The polymerization reactions were performed by three different mechanisms for the controlled polymerization—sequential anionic polymerization, atomic transfer radical polymerization and the combination of those two methods. In sequential anionic polymerization and in atomic transfer radical polymerization block-copolymers of the desired composition were obtained but with the Mn significantly lower than desired (up to 30). The polymerization of the block-copolymers of the higher Mn was unsuccessful, and the possible mechanisms for the unwanted side reactions are discussed. It is also concluded that combination of sequential anionic polymerization and atomic transfer radical polymerization is not suitable for this system as polystyrene macroinitiator cannot initiate the polymerization of poly(2-(methoxyethoxy)ethyl methacrylate).

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Alsubaie, Fehaid M., Othman Y. Alothman, Hassan Fouad, and Abdel-Hamid I. Mourad. "ABC-Type Triblock Copolyacrylamides via Copper-Mediated Reversible Deactivation Radical Polymerization." Polymers 14, no. 1 (December 29, 2021): 116. http://dx.doi.org/10.3390/polym14010116.

Повний текст джерела

Анотація:

The aqueous Cu(0)-mediated reversible deactivation radical polymerization (RDRP) of triblock copolymers with two block sequences at 0.0 °C is reported herein. Well-defined triblock copolymers initiated from PHEAA or PDMA, containing (A) 2-hydroxyethyl acrylamide (HEAA), (B) N-isopropylacrylamide (NIPAM) and (C) N, N-dimethylacrylamide (DMA), were synthesized. The ultrafast one-pot synthesis of sequence-controlled triblock copolymers via iterative sequential monomer addition after full conversion, without any purification steps throughout the monomer additions, was performed. The narrow dispersities of the triblock copolymers proved the high degree of end-group fidelity of the starting macroinitiator and the absence of any significant undesirable side reactions. Controlled chain length and extremely narrow molecular weight distributions (dispersity ~1.10) were achieved, and quantitative conversion was attained in as little as 52 min. The full disproportionation of CuBr in the presence of Me6TREN in water prior to both monomer and initiator addition was crucially exploited to produce a well-defined ABC-type triblock copolymer. In addition, the undesirable side reaction that could influence the living nature of the system was investigated. The ability to incorporate several functional monomers without affecting the living nature of the polymerization proves the versatility of this approach.

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Kadokawa, Jun-ichi. "Chemoenzymatic synthesis of functional amylosic materials." Pure and Applied Chemistry 86, no. 5 (May 19, 2014): 701–9. http://dx.doi.org/10.1515/pac-2013-1116.

Повний текст джерела

Анотація:

AbstractIn this article, a review of the chemoenzymatic synthesis of functional amylosic materials by means of a-glucan phosphorylase-catalyzed enzymatic polymerization is presented. The first topic of this review deals with the synthesis of amylose-grafted heteropolysaccharides composed of abundant polysaccharide main chains, such as chitin/chitosan, cellulose, alginate, xanthan gum, and carboxymethyl cellulose. The synthesis was achieved by combining the a-glucan phosphorylase-catalyzed enzymatic polymerization forming amylose with the appropriate chemical reaction (chemoenzymatic method). The second topic is the construction of amylosic supramolecular materials such as hydrogels and films by means of the vine-twining polymerization approach, which is a method for the formation of amylose-polymer inclusion complexes in the a-glucan phosphorylase-catalyzed polymerization field. In these studies, the designed graft copolymeric guest compounds were first synthesized. Then, the a-glucan phosphorylase-catalyzed enzymatic polymerization was carried out in the presence of the graft copolymers to produce the amylosic supramolecular materials through the formation of inclusion complexes.

Стилі APA, Harvard, Vancouver, ISO та ін.

Статті в журналах з теми "Functional copolymers"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями