Articoli di riviste: "Grafted silica nanoparticle"

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Henoumont, Céline, Gauthier Hallot, Estelle Lipani, Catherine Gomez, Robert N. Muller, Luce Vander Elst, Marc Port e Sophie Laurent. "Characterization of Organic Molecules Grafted to Silica or Bismuth Nanoparticles by NMR". Applied Nano 2, n. 4 (4 novembre 2021): 330–43. http://dx.doi.org/10.3390/applnano2040024.

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NMR is a powerful characterization tool and we propose to study the surface of silica or bismuth nanoparticles dedicated to medical applications in order to evidence the covalent grafting of organic molecules on their surface. For that aim, DOSY experiments are particularly useful and allow for the discrimination of molecules interacting strongly with the nanoparticle surface from molecules simply weakly adsorbed at the surface. We were able to characterize thoroughly the surface of different silica and bismuth nanoparticles.

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Holt, Adam P., e C. M. Roland. "Segmental and secondary dynamics of nanoparticle-grafted oligomers". Soft Matter 14, n. 42 (2018): 8604–11. http://dx.doi.org/10.1039/c8sm01443d.

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Huang, Shaping, Liping Song, Zhidong Xiao, Yue Hu, Meiwen Peng, Jinquan Li, Xinsheng Zheng, Bin Wu e Chao Yuan. "Graphene quantum dot-decorated mesoporous silica nanoparticles for high aspirin loading capacity and its pH-triggered release". Analytical Methods 8, n. 12 (2016): 2561–67. http://dx.doi.org/10.1039/c5ay03176a.

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Rose, Katie A., Daeyeon Lee e Russell J. Composto. "pH-Mediated nanoparticle dynamics in hydrogel nanocomposites". Soft Matter 17, n. 10 (2021): 2765–74. http://dx.doi.org/10.1039/d0sm02213f.

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The effect of static silica particles on the dynamics of quantum dot (QD) nanoparticles grafted with a poly(ethylene glycol) (PEG) brush in hydrogel nanocomposites is investigated using single particle tracking (SPT).

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Zhou, Tong Hui, Wen Hong Ruan, Min Zhi Rong e Ming Qiu Zhang. "In Situ Crosslinking Induced Structure Development and Mechanical Properties of Nano-Silica/Polypropylene Composites". Key Engineering Materials 334-335 (marzo 2007): 733–36. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.733.

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In our previous works, a double percolation mechanism of stress volumes was proposed to explain the special effects generated by small amounts of grafted nanoparticles. Accordingly, it is inferred that strengthening nanoparticle agglomerates and enhancing nanoparticles/polymer matrix interfacial interaction are the key issues to improve mechanical performance of the matrix polymer. To confirm this idea, in-situ crosslinking was adopted to prepare nanocomposites by adding reactive monomers and crosslinking agents during melt compounding of nano-silica with polypropylene (PP). It was found that the grafted polymer chains were successfully crosslinked and chemically bonded to the nano-silica forming crosslinked networks. Meanwhile, matrix molecular chains penetrated through the networks to establish the so-called semi-IPN structure that interconnected nanoparticles by the networks and improved filler/matrix interfacial interaction. As a result, the tiny nanoparticles were well distributed in the matrix and the toughening and reinforcing effects of the nanoparticles on the matrix were brought into play at rather low filler loading, as evidenced by mechanical performance tests. Besides, β-crystal was detected in the nanocomposites experienced in-situ crosslinking reaction.

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Paramelle, David, Sergey Gorelik, Ye Liu e Jatin Kumar. "Photothermally responsive gold nanoparticle conjugated polymer-grafted porous hollow silica nanocapsules". Chemical Communications 52, n. 64 (2016): 9897–900. http://dx.doi.org/10.1039/c6cc04187f.

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Sabouri, Hadi, Yun Huang, Kohji Ohno e Sébastien Perrier. "Silica core–polystyrene shell nanoparticle synthesis and assembly in three dimensions". Nanoscale 7, n. 45 (2015): 19036–46. http://dx.doi.org/10.1039/c5nr06400g.

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Liu, Bin, Stéphanie Exiga, Etienne Duguet e Serge Ravaine. "Templated Synthesis and Assembly of Two-, Three- and Six-Patch Silica Nanoparticles with a Controlled Patch-to-Particle Size Ratio". Molecules 26, n. 16 (5 agosto 2021): 4736. http://dx.doi.org/10.3390/molecules26164736.

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We report a fabrication route of silica nanoparticles with two, three or six patches with an easily tunable patch-to-particle size ratio. The synthetic pathway includes two main stages: the synthesis of silica/polystyrene multipod-like templates and the selective growth of their silica core through an iterative approach. Electron microscopy of the dimpled nanoparticles obtained after dissolution of the polystyrene nodules of the multipod-like nanoparticles provides evidence of the conformational growth of the silica core. Thanks to the presence of some polymer chains, which remained grafted at the bottom of the dimples after the dissolution of the PS nodules, the solvent-induced assembly of the patchy nanoparticles is performed. Chains, hexagonal suprastructures and cubic lattices are obtained from the assembly of two-, three- and six-patch silica nanoparticles, respectively. Our study can guide future work in both patchy nanoparticle synthesis and self-assembly. It also opens new routes towards the fabrication of specific classes of one-, two- and three-dimensional colloidal lattices, including complex tilings.

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Yokoyama, Ruriko, Seiko Suzuki, Kumi Shirai, Takeshi Yamauchi, Norio Tsubokawa e Makoto Tsuchimochi. "Preparation and properties of biocompatible polymer-grafted silica nanoparticle". European Polymer Journal 42, n. 12 (dicembre 2006): 3221–29. http://dx.doi.org/10.1016/j.eurpolymj.2006.08.015.

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Kim, Gi-Hong, Dong-Ho Kang, Bich-Nam Jung e Jin-Kie Shim. "Fabrication and Characterization of Hydrophobic Cellulose Nanofibrils/Silica Nanocomposites with Hexadecyltrimethoxysilane". Polymers 14, n. 4 (21 febbraio 2022): 833. http://dx.doi.org/10.3390/polym14040833.

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Cellulose nanofibrils (CNFs) have attracted much attention because of their renewability and potential biocompatibility. However, CNFs are extremely hydrophilic due to the presence of a large number of hydroxyl groups, limiting their use as a water-resistant material. In this work, we controlled the adsorption behavior of silica nanoparticles on the surface of CNFs by adjusting the synthesis conditions. The silica nanoparticle size and packing efficiency on the CNF surface could be controlled by varying the ammonium hydroxide and water concentrations. In addition, hexadecyltrimethoxysilane (HDTMS) was successfully grafted onto CNF or CNF/silica nanocomposite surfaces, and the quantitative content of organic/inorganic substances in HDTMS was analyzed through XPS and TGA. The HDTMS-modified CNF/silica nanocomposites were more advantageous in terms of hydrophobicity than the HDTMS-modified CNF composites. This is because the silica nanoparticles were adsorbed on the surface of the CNFs, increasing the surface roughness and simultaneously increasing the amount of HDTMS. As a result, the HDTMS-modified CNFs showed a water contact angle (WCA) of ~80°, whereas HDTMS-modified CNF/silica nanocomposites obtained superhydrophobicity, with a WCA of up to ~159°. This study can provide a reference for the expansion of recyclable eco-friendly coating materials via the adsorption of silica nanoparticles and hydrophobic modification of CNF materials.

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Keller, Christopher B., Julia S. Siqueira e Scott M. Grayson. "Oil Encapsulation Advantages of Amphiphilic Polymer-Grafted Silica Nanoparticle Systems". ACS Applied Polymer Materials 3, n. 11 (28 ottobre 2021): 5893–902. http://dx.doi.org/10.1021/acsapm.1c01110.

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Takamura, Masaaki, Takeshi Yamauchi e Norio Tsubokawa. "Preparation and dispersibility of poly(L-lactide)-grafted silica nanoparticle". Journal of Applied Polymer Science 124, n. 5 (27 novembre 2011): 3854–60. http://dx.doi.org/10.1002/app.35523.

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Schadler, Linda S., Sarah L. Lewis, Jun Wei Yang e Brian C. Benicewicz. "Polymer Nanocomposites with Designed Interfaces". Key Engineering Materials 334-335 (marzo 2007): 909–12. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.909.

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This paper shows preliminary results for polymer nanocomposites consisting of “hairy” silica particles with grafted polystyrene in polystyrene matrices of controlled molecular weight and polydispersity. The goal of the work is to tailor the degree of wetting / interaction between the particles and polymer by controlling the graft density and molecular weight of the grafted polymer. This is providing an opportunity to study the properties of the interface region and to control the bulk composite properties. We have found that the predictions for flat brushes are qualitatively, but not quantitatively, applicable and that the highly curved surfaces of nanoparticles present several challenges for the design of nanoparticle interfaces. The talk will present more complete results in this system and provide an overview of other work in our group using tailored interfaces to control nanocomposite properties.

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Lorenzo, Arnaldo T., Ramakrishna Ponnapati, Tirtha Chatterjee e Ramanan Krishnamoorti. "Structural characterization of aqueous solution poly(oligo(ethylene oxide) monomethyl methacrylate)-grafted silica nanoparticles". Faraday Discussions 186 (2016): 311–24. http://dx.doi.org/10.1039/c5fd00137d.

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The structure of aqueous dispersions of poly(oligo(ethylene oxide) monomethyl methacrylate)-grafted silica nanoparticles was characterized using contrast variation small-angle neutron scattering studies. Modeling the low hybrid concentration dispersion scattering data using a fuzzy sphere and a polydisperse core–shell model, demonstrated that the polymer chains are highly swollen in the dispersions as compared to the dimensions of the free polymer chains in dilute solution. At higher hybrid concentrations, the dispersions were well described using a Percus–Yevick approximation to describe the structure factor. These structural characterization tools are excellent starting points for effective molecular level descriptors of dewetting and macroscopic phase transitions for polymer tethered hybrid nanoparticle systems.

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Xie, M. X., L. Jiang, Z. P. Xu e D. Y. Chen. "Monofunctional polymer nanoparticles prepared through intramolecularly cross-linking the polymer chains sparsely grafted on the surface of sacrificial silica spheres". Chemical Communications 51, n. 10 (2015): 1842–45. http://dx.doi.org/10.1039/c4cc07885c.

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Eriksson, Maria, Joris Hamers, Ton Peijs e Han Goossens. "The Influence of Graft Length and Density on Dispersion, Crystallisation and Rheology of Poly(ε-caprolactone)/Silica Nanocomposites". Molecules 24, n. 11 (3 giugno 2019): 2106. http://dx.doi.org/10.3390/molecules24112106.

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Different techniques of grafting polymer chains to filler surfaces are often employed to compatibilise filler and polymer matrices. In this paper the influence of graft length and graft density on the state of dispersion, crystallisation and rheological properties of poly(ε-caprolactone) (PCL)/silica (SiO2) nanocomposites are reported. Grafted silica nanoparticles were prepared through polymerisation of PCL from the nanoparticle surface. Graft length was controlled by the reaction time, while the grafting density was controlled by the monomer-to-initiator ratio. Grafted nanoparticles were mixed with PCL of different molecular weights and the state of dispersion was assessed. Different matrix-to-graft molecular weight ratios resulted in different states of dispersion. Composites based on the higher molecular weight matrix exhibited small spherical agglomerates while the lower molecular weight matrix revealed more sheet-like microstructures. The state of dispersion was found to be relatively independent of graft length and density. Under quiescent conditions the grafts showed increased nucleation ability in the higher molecular weight PCL, while in the lower molecular weight matrix the effect was less pronounced. Rheological experiments showed an increase in viscosity with increased filler content, which was beneficial for the formation of oriented structures in shear-induced crystallisation.

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Romero, Marcelo R., Alicia V. Veglia, Maria Valeria Amé e Angel Guillermo Bracamonte. "Multimodal Spectroscopy Assays for Advanced Nano-Optics Approaches by Tuning Nano-Tool Surface Chemistry and Metal-Enhanced Fluorescence". Crystals 14, n. 4 (31 marzo 2024): 338. http://dx.doi.org/10.3390/cryst14040338.

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In this research work, different chemical modifications were applied to gold nanoparticles and their use in enhanced non-classical light emitters based on metal-enhanced fluorescence (MEF) was evaluated. In order to achieve this, gold core–shell nanoparticles with silica shells were modified via multilayered addition and the incorporation of a covalently linked laser dye to develop MEF. Their inter-nanoparticle interactions were evaluated by using additional silica shell multilayers and modified cyclodextrin macrocycles. In this manner, the sizes and chemical surface interactions on the multilayered nanoarchitectures were varied. These optical active nanoplatforms led to the development of different nanoassembly sizes and luminescence behaviors. Therefore, the interactions and nanoassembly properties were evaluated by using various spectroscopic and nanoimaging techniques. Highly dispersible gold core–shell nanoparticles with diameters of 50–60 nm showed improved colloidal dispersion that led to single ultraluminescent gold core–shell nanoparticles with MEF. Then, the addition of variable silica lengths produced increased interactions and consequent nanoaggregation. However, the silanized nanoparticles were easily dispersible after agitation or sonication. Thus, their sizes were proportional only to the diameter and the van de Waals interaction did not affect their sizes in bulk. Then, the covalent linking of different concentrations of modified cyclodextrins was applied to the chemical surfaces by incorporating additional hydroxyl groups from the glucose monomeric unities of cyclodextrins. In this manner, variable larger-sized and inter-branched grafted gold core–shell silica nanoparticles were generated. The ultraluminescent properties were conserved due to the non-optical activity of the cyclodextrins. However, they generated enhanced ultraluminescence phenomena. Laser fluorescence microscopy nanoimaging showed enhanced resolutions in comparison to non-grafted supramolecular gold core–shell nanoparticles. The differences in their interactions and the sizes of the nanoassemblies were explained by their single nanoparticle diameters and the interacting chemical groups on their nanosurfaces. While the varied luminescence emissions generated were tuned by plasmonics, enhanced plasmonic phenomena and light scattering properties were seen depending on the type of nanoassembly. Thus, optically active and non-optically active materials led to different optical properties in the bright field and enhanced the excited state within the electromagnetic near-field of the gold nanotemplates. In this manner, it was possible to achieve high sensitivity by varying the spacer lengths and optical properties. Therefore, further perspectives regarding the design of nano-tools composed of light for various applications were discussed.

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Wahyuningsih, Kendri, Sri Yuliani e Hoerudin Hoerudin. "Characteristics of Silica Nanoparticles from Rice Husk as Influenced by Surface Modification with Used Solvent Containing Silane". Journal of Engineering and Technological Sciences 53, n. 4 (3 agosto 2021): 210403. http://dx.doi.org/10.5614/j.eng.technol.sci.2021.53.4.3.

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Silica extracted from rice husk (silica nanoparticles, Si-NP RHA) has great potential for industrial use, particularly as filler in the rubber industry. However, silica is poorly dispersed in the matrix and needs to be modified by a silane linking agent (bis-(3-triethoxysilylpropyl) tetrasulfane (TESPT)) to improve its mixing properties. As a result, a large amount of used solvent containing silane TESPT is produced. This study aimed to evaluate the surface modification of silica nanoparticles from rice husk employing this used solvent and to characterize the particles’ physical properties. Silica nanoparticles were extracted from rice husk using a sol-gel method. FTIR spectography demonstrated that the TESPT on fresh solvent and the used solvent were successfully grafted onto the surface of Si-NP RHA. Si-NP RHA modified by Two Step Modification (TSM) employing used solvent had strong absorption peaks at wave numbers of 2927.94 cm-1 and 1446.61 cm-1, which are associated with vibration of the ‑CH2 group and deforming vibration of the -C-H group in TESPT compounds. Likewise, Si-NP RHA modified with One Step Modification (OSM), either using fresh solvent or the used solvent, exhibited absorption peaks at wave numbers 2935.66 cm-1 and 1404.18 cm-1. The result showed that the used solvent still effectively modified the silica nanoparticle surface.

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Hu, Sha-Ni, Yu Lin e Guo-Zhang Wu. "Nanoparticle Dispersion and Glass Transition Behavior of Polyimide-grafted Silica Nanocomposites". Chinese Journal of Polymer Science 38, n. 1 (30 agosto 2019): 100–108. http://dx.doi.org/10.1007/s10118-019-2300-6.

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Du, Dongyuan, Yujing Tang, Lu Yang e Chao Tang. "Effects of Different Grafting Density of Amino Silane Coupling Agents on Thermomechanical Properties of Cross-Linked Epoxy Resin". Polymers 12, n. 8 (26 luglio 2020): 1662. http://dx.doi.org/10.3390/polym12081662.

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In order to study the influences of amino silane coupling agents with different grafting densities on the surface of nano silica on the thermomechanical properties of cross-linked epoxy resin, the molecular dynamics method was used to establish an amorphous model and calculate the mechanical properties, glass transition temperature, mean square displacement, hydrogen bond, binding energy, and radial distribution function of the composite models in this paper. The results are as follows: with the increase of the grafting density of an amino silane coupling agent on the surface of nano silica particles, the mechanical properties and glass transition temperature of epoxy resin showed a trend of increasing first and then decreasing. When the grafting ratio was 9%, the mechanical properties and glass transition temperature of the epoxy resin were the largest, and the glass transition temperature was increased by 41 K. At the same time, it was found that the higher the grafting ratio, the lower the chain movement ability, but the higher the binding energy. Besides, the binding energy between the nanoparticles of the grafted silane coupling agent and epoxy resin was negatively correlated with the temperature. By analyzing the hydrogen bond and radial distribution function, the results showed that the improvement of the grafted silane coupling agent on the surface of the nanoparticle to the thermomechanical properties of the epoxy resin was related to the OH···O and NH···O hydrogen bonds. The analysis results indicated that the proper grafting density should be selected based on the established model size, selected nanoparticle diameter, and epoxy resin materials in order to better improve the thermomechanical properties of the epoxy resin.

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Zhang, Liqian, e Yan Sun. "Poly(carboxybetaine methacrylate)-grafted silica nanoparticle: A novel carrier for enzyme immobilization". Biochemical Engineering Journal 132 (aprile 2018): 122–29. http://dx.doi.org/10.1016/j.bej.2018.01.013.

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Beagan, Abeer, Shatha Lahmadi, Ahlam Alghamdi, Majed Halwani, Mohammed Almeataq, Abdulaziz Alhazaa, Khalid Alotaibi e Abdullah Alswieleh. "Glucosamine Modified the Surface of pH-Responsive Poly(2-(diethylamino)ethyl Methacrylate) Brushes Grafted on Hollow Mesoporous Silica Nanoparticles as Smart Nanocarrier". Polymers 12, n. 11 (20 novembre 2020): 2749. http://dx.doi.org/10.3390/polym12112749.

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This work presents the synthesis of pH-responsive poly(2-(diethylamino) ethyl methacrylate) (PDEAEMA) brushes anchored on hollow mesoporous silica nanoparticles (HMSN-PDEAEMA) via a surface-initiated ARGET ATRP technique. The average size of HMSNs was ca. 340 nm, with a 90 nm mesoporous silica shell. The dry thickness of grafted PDEAEMA brushes was estimated to be ca 30 nm, as estimated by SEM and TEM. The halogen group on the surface of PDEAMA brushes was successfully derivatized with glucosamine, as confirmed by XPS. The effect of pH on the size of the hybrid nanoparticles was investigated by DLS. The size of fabricated nanoparticle decreased from ca. 950 nm in acidic media to ca. 500 nm in basic media due to the deprotonation of tertiary amine in the PDEAEMA. The PDEAEMA modified HMSNs nanocarrier was efficiently loaded with doxorubicin (DOX) with a loading capacity of ca. 64%. DOX was released in a relatively controlled pH-triggered manner from hybrid nanoparticles. The cytotoxicity studies demonstrated that DOX@HMSN-PDEAEMA-Glucosamine showed a strong ability to kill breast cancer cells (MCF-7 and MCF-7/ADR) at low drug concentrations, in comparison to free DOX.

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Zhang, Ming Qiu, Min Zhi Rong e Klaus Friedrich. "Polymer Nanocomposites as Candidates for Tribological Applications". Materials Science Forum 539-543 (marzo 2007): 842–47. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.842.

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To develop wear resistant nanocomposite coating materials, the authors treated nanosilica first by introducing a certain amount of grafting polymers onto the particles in terms of an irradiation technique. Through irradiation grafting, the nanoparticle agglomerates turn into a nano-composite microstructure, which in turn built up a strong interfacial interaction with the surrounding epoxy matrix during the subsequent mixing and consolidation. The experimental results indicated that the addition of the grafted nanosilica into epoxy significantly reduced wear rate and frictional coefficient of the matrix at low filler loading. Compared with the cases of microsized silica and untreated nanosilica, the employment of grafted nanosilica provided the composites with much higher tribological performance enhancement efficiency.

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Kawahara, Takashi, Yoko Takeuchi, Gang Wei, Kumi Shirai, Takeshi Yamauchi e Norio Tsubokawa. "Preparation of Antibacterial Polymer-Grafted Silica Nanoparticle and Surface Properties of Composites Filled with the Silica (2)". Polymer Journal 41, n. 9 (2009): 744–51. http://dx.doi.org/10.1295/polymj.pj2009026.

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Xia, Shuang, Xiaobing Liu, Jianfeng Wang, Ze Kan, Hong Chen, Wenxin Fu e Zhibo Li. "Role of poly(ethylene glycol) grafted silica nanoparticle shape in toughened PLA-matrix nanocomposites". Composites Part B: Engineering 168 (luglio 2019): 398–405. http://dx.doi.org/10.1016/j.compositesb.2019.03.050.

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Zhang, Lei, Guo Wei Zhou e Min Nan Zhao. "Preparation and Characterization of SiO₂-PMMA with Different Shell Thickness Using AGET ATRP". Advanced Materials Research 634-638 (gennaio 2013): 1951–54. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.1951.

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Monodispersed SiO2-core/PMMA-shell composite nanospheres have been prepared via activator generated by electron transfer atom transfer radical polymerization (AGET ATRP) mediated by an iron (III) catalyst. By simply adjusting the amount of monomer, the shell thickness of products can easily be tuned. Samples were characterized by FT-IR, TEM, 1H NMR. The results showed that the sphere structure kept unchanging after grafting. FT-IR and 1H NMR measurements show that the polymer was grafted on the silica surface successfully. TEM results for composite nanospheres suggested the core-shell-like structure of the hybrid nanoparticle.

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Alswieleh, Abdullah M., Abeer M. Beagan, Bayan M. Alsheheri, Khalid M. Alotaibi, Mansour D. Alharthi e Mohammed S. Almeataq. "Hybrid Mesoporous Silica Nanoparticles Grafted with 2-(tert-butylamino)ethyl Methacrylate-b-poly(ethylene Glycol) Methyl Ether Methacrylate Diblock Brushes as Drug Nanocarrier". Molecules 25, n. 1 (3 gennaio 2020): 195. http://dx.doi.org/10.3390/molecules25010195.

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This paper introduces the synthesis of well-defined 2-(tert-butylamino)ethyl methacrylate-b-poly(ethylene glycol) methyl ether methacrylate diblock copolymer, which has been grafted onto mesoporous silica nanoparticles (PTBAEMA-b-PEGMEMA-MSNs) via atom transfer radical polymerization (ATRP). The ATRP initiators were first attached to the MSN surfaces, followed by the ATRP of 2-(tert-butylamino)ethyl methacrylate (PTBAEMA). CuBr2/bipy and ascorbic acid were employed as the catalyst and reducing agent, respectively, to grow a second polymer, poly(ethylene glycol) methyl ether methacrylate (PEGMEMA). The surface structures of these fabricated nanomaterials were then analyzed using Fourier Transform Infrared (FTIR) spectroscopy. The results of Thermogravimetric Analysis (TGA) show that ATRP could provide a high surface grafting density for polymers. Dynamic Light Scattering (DLS) was conducted to investigate the pH-responsive behavior of the diblock copolymer chains on the nanoparticle surface. In addition, multifunctional pH-sensitive PTBAEMA-b-PEGMEMA-MSNs were loaded with doxycycline (Doxy) to study their capacities and long-circulation time.

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Chowdhury, P., P. Mondal e K. Roy. "Synthesis of polyaniline nanoparticle grafted silica gel and study of its Cr(VI) binding property". Journal of Applied Polymer Science 119, n. 2 (27 luglio 2010): 823–29. http://dx.doi.org/10.1002/app.32790.

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Zhang, Yang, e Juan Xu. "Mesoporous silica nanoparticle-based intelligent drug delivery system for bienzyme-responsive tumour targeting and controlled release". Royal Society Open Science 5, n. 1 (gennaio 2018): 170986. http://dx.doi.org/10.1098/rsos.170986.

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This paper proposes a novel type of multifunctional envelope-type mesoporous silica nanoparticle (MSN) to achieve cancer cell targeting and drug-controlled release. In this system, MSNs were first modified by active targeting moiety hyaluronic acid (HA) for breast cancer cell targeting and hyaluronidases (Hyal)-induced intracellular drug release. Then gelatin, a proteinaceous biopolymer, was grafted onto the MSNs to form a capping layer via glutaraldehyde-mediated cross-linking. To shield against unspecific uptake of cells and prolong circulation time, the nanoparticles were further decorated with poly(ethylene glycol) polymers (PEG) to obtain MSN@HA-gelatin-PEG (MHGP). Doxorubicin (DOX), as a model drug, was loaded into PEMSN to assess the breast cancer cell targeting and drug release behaviours. In vitro study revealed that PEG chains protect the targeting ligand and shield against normal cells. After reaching the breast cancer cells, MMP-2 overpressed by cells hydrolyses gelatin layer to deshield PEG and switch on the function of HA. As a result, DOX-loaded MHGP was selectively trapped by cancer cells through HA receptor-mediated endocytosis and subsequently release DOX due to Hyal-catalysed degradation of HA. This system presents successful bienzyme-responsive targeting drug delivery in an optimal fashion and provides potential applications for targeted cancer therapy.

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Figari, Giorgia, José L. M. Gonçalves, Hermínio P. Diogo, Madalena Dionísio, José Paulo Farinha e María Teresa Viciosa. "Understanding Fenofibrate Release from Bare and Modified Mesoporous Silica Nanoparticles". Pharmaceutics 15, n. 6 (30 maggio 2023): 1624. http://dx.doi.org/10.3390/pharmaceutics15061624.

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To investigate the impact of the surface functionalization of mesoporous silica nanoparticle (MSN) carriers in the physical state, molecular mobility and the release of Fenofibrate (FNB) MSNs with ordered cylindrical pores were prepared. The surface of the MSNs was modified with either (3-aminopropyl) triethoxysilane (APTES) or trimethoxy(phenyl)silane (TMPS), and the density of the grafted functional groups was quantified via 1H-NMR. The incorporation in the ~3 nm pores of the MSNs promoted FNB amorphization, as evidenced via FTIR, DSC and dielectric analysis, showing no tendency to undergo recrystallization in opposition to the neat drug. Moreover, the onset of the glass transition was slightly shifted to lower temperatures when the drug was loaded in unmodified MSNs, and MSNs modified with APTES composite, while it increased in the case of TMPS-modified MSNs. Dielectric studies have confirmed these changes and allowed researchers to disclose the broad glass transition in multiple relaxations associated with different FNB populations. Moreover, DRS showed relaxation processes in dehydrated composites associated with surface-anchored FNB molecules whose mobility showed a correlation with the observed drug release profiles.

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Huang, Guohui, Xiaoxuan Liu, Yiling Bei e Huiqing Ma. "Facile TEMPO Immobilization onto Poly(acrylic acid)-Modified Magnetic Nanoparticles: Preparation and Property". International Journal of Polymer Science 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/9621635.

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Adding catalysts to magnetic polyvalent supports facilitating catalyst recycling and recovery seems feasible. Polymer-modified magnetic nanocomposites for organocatalyst immobilization are a plausible approach to this technology. Here, we present facile and efficient method for 2,2′,6,6′-tetramethylpiperidinyl-1-oxy (TEMPO) immobilization onto polymer-modified magnetic nanoparticles under mild reaction conditions. Poly(acrylic acid) was chosen to graft from magnetic nanoparticle through a simple inverse emulsion polymerization technique. The resulting poly(acrylic acid) magnetic nanocomposite is an ideal material to immobilize the organocatalyst 4-hydroxy-2,2′,6,6′-tetramethylpiperidinyl-1-oxy (H-TEMPO) via an esterification reaction with pendant carboxyl group on the polymer chain. Instrumental analysis confirmed that poly(acrylic acid) chain was grafted on the silica-coated magnetic particles by this simple method while maintaining their magnetic properties; elemental analysis indicated that TEMPO was efficiently immobilized onto the polymer chain. The catalysis tests under both Anelli and Minisci system showed that the nanocomposite catalyst exhibits proper selectivity and activity for the alcohol/aldehyde transformation. Recycling experiments showed that stability and reusability of the nanocomposite catalyst were satisfying.

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Mu, Bin, Tingmei Wang e Peng Liu. "Well-Defined Dendritic-Graft Copolymer Grafted Silica Nanoparticle by Consecutive Surface-Initiated Atom Transfer Radical Polymerizations". Industrial & Engineering Chemistry Research 46, n. 10 (maggio 2007): 3069–72. http://dx.doi.org/10.1021/ie070252+.

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Komathi, Shanmugasundaram, Anantha Iyengar Gopalan e Kwang-Pill Lee. "Nanomolar detection ofdopamine at multi-walled carbon nanotube grafted silica network/gold nanoparticle functionalised nanocomposite electrodes". Analyst 135, n. 2 (2010): 397–404. http://dx.doi.org/10.1039/b918335c.

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Pan, Yiting, Haihong Bai, Guocheng Zhang, Wei Liu, Yanqi Wu, Hui Chen, Ying Tian et al. "A Novel Silica Hybrid Nanoparticle with Zwitterion-Functionalized Polymer Chains for Highly Efficient N-Glycan Enrichment". Journal of Biomedical Nanotechnology 19, n. 8 (1 agosto 2023): 1495–502. http://dx.doi.org/10.1166/jbn.2023.3553.

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Abstract (sommario):

N-Glycosylation is one of the most common and important protein posttranslational modifications. Structural aberrations of the N-glycans branching from glycoproteins are closely related to various disease occurrences and progressions. Therefore, global systematic identification of disease-related N-glycans not only largely facilitates the understanding of their cellular functions but also promotes the development of new diagnostic and therapeutic biomarkers. However, N-glycans are low in abundance and hydrophilic, thereby hindering high-throughput, and large-scale N-glycan analysis and N-glycoproteome research. Here, a zwitterion-functionalized polymer brush-grafted silica hybrid hydrophilic material (poly-SBMA-S) was fabricated by in situ growth of polymeric [2-(methacryloyloxy)ethyl]dimethyl(3-sulfopropyl)ammonium hydroxide (SBMA) chains on porous silica particles through a surface-initiated atom transfer radical polymerization technique, and it was used as a new stationary phase for highly selective N-glycan enrichment. Human plasma demonstrated 64 N-glycans due to the densely packed polyzwitterion chains and the significantly increased coverage of hydrophilic binding sites, demonstrating the high potential of the new hydrophilic matrix in the profiling and analysis of N-glycans and other hydrophilic targets.

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Wu, Litao, Hua Pan, Weilan Huang, Zhongxuan Hu, Meijing Wang e Fang Zhang. "pH and Redox Dual-Responsive Mesoporous Silica Nanoparticle as Nanovehicle for Improving Fungicidal Efficiency". Materials 15, n. 6 (17 marzo 2022): 2207. http://dx.doi.org/10.3390/ma15062207.

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Prochloraz (Pro) controlled-release nanoparticles (NPs) based on bimodal mesoporous silica (BMMs) with redox and pH dual responses were successfully prepared in this study. BMMs was modified by a silane coupling agent containing a disulfide bond, and β-cyclodextrin (β-CD) was grafted on the surface of the NPs through host–guest interaction. Pro was encapsulated into the pores of nanoparticles by physical adsorption. NPs had a spherical structure, and their average diameter was 546.4 ± 3.0 nm as measured by dynamic light scattering. The loading rate of Pro was 28.3%, and it achieved excellent pH/redox dual-responsive release performance under acidic conditions. Foliage adhesion tests on tomato leaves showed that the NPs had good adhesion properties compared to the commercial formulation. Owing to the protection of the nanocarrier, NPs became more stable under ultraviolet light and high temperature, which improves the efficient utilization of Pro. Biological activity tests showed that the NPs exhibited effective antifungal activity, and the benign biosafety of the nanocarrier was also observed through toxicology tests on cell viability and the growth of Escherichiacoli (E. coli). This work provides a promising approach to improving the efficient utilization of pesticides and reducing environmental pollution.

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Petousis, Markos, Lazaros Tzounis, Dimitrios Papageorgiou e Nectarios Vidakis. "Decoration of SiO2 and Fe3O4 Nanoparticles onto the Surface of MWCNT-Grafted Glass Fibers: A Simple Approach for the Creation of Binary Nanoparticle Hierarchical and Multifunctional Composite Interphases". Nanomaterials 10, n. 12 (13 dicembre 2020): 2500. http://dx.doi.org/10.3390/nano10122500.

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We report on a versatile method for chemically grafting multiwalled carbon nanotubes (MWCNTs) onto the surface of conventional glass fibers (GFs), as well as depositing further silica (SiO2) or superparamagnetic (SPM) magnetite (Fe3O4) nanoparticles (NPs) creating novel hierarchical reinforcements. The CNT-grafted GFs (GF-CNT) were utilized further as the support to decorate nano-sized SiO2 or Fe3O4 via electrostatic interactions, resulting finally into double hierarchy reinforcements. SiO2 NPs were first used as model nano-particulate objects to investigate the interfacial adhesion properties of binary coated GFs (denoted as GF-CNT/SiO2) in epoxy matrix via single fiber pull-out (SFPO) tests. The results indicated that the apparent interfacial shear strength (IFSS or τapp) was significantly increased compared to the GF-CNT. Fe3O4 NPs were assembled also onto CNT-grafted GFs resulting into GF-CNT/Fe3O4. The fibers exhibited a magnetic response upon being exposed to an external magnet. Scanning electron microscopy (SEM) revealed the surface morphologies of the different hierarchical fibers fabricated in this work. The interphase microstructure of GF-CNT and GF-CNT/SiO2 embedded in epoxy was investigated by transmission electron microscopy (TEM). The hybrid and hierarchical GFs are promising multifunctional reinforcements with appr. 85% increase of the IFSS as compared to typical amino-silane modified GFs. It could be envisaged that, among other purposes, GF-CNT/Fe3O4 could be potentially recyclable reinforcements, especially when embedded in thermoplastic polymer matrices.

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Li, Dexiong, Yubei Qiu, Sihui Zhang, Mi Zhang, Zexi Chen e Jiang Chen. "A Multifunctional Antibacterial and Osteogenic Nanomedicine: QAS-Modified Core-Shell Mesoporous Silica Containing Ag Nanoparticles". BioMed Research International 2020 (19 settembre 2020): 1–15. http://dx.doi.org/10.1155/2020/4567049.

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Treatments for infectious bone defects such as periodontitis require antibacterial and osteogenic differentiation capabilities. Nanotechnology has prompted the development of multifunctional material. In this research, we aim to synthesize a nanoparticle that can eliminate periodontal pathogenic microorganisms and simultaneously stimulate new bone tissue regeneration and mineralization. QAS-modified core-shell mesoporous silica containing Ag nanoparticles (Ag@QHMS) was successfully synthesized through the classic hydrothermal method and surface quaternary ammonium salt functionalization. The Ag@QHMS in vitro antibacterial activity was explored via coculture with Staphylococcus aureus, Escherichia coli, and Porphyromonas gingivalis biofilms. Bone mesenchymal stem cells (BMSCs) were selected for observing cytotoxicity, apoptosis, and osteogenic differentiation. Ag@QHMS showed a good sustained release profile of Ag+ and a QAS-grafted mesoporous structure. Compared with the single-contact antibacterial activity of QHMS, Ag@QHMS exhibited a more efficient and stable concentration-dependent antimicrobial efficacy; the minimum inhibitory concentration was within 100 μg/ml, which was below the BMSC biocompatibility concentration (200 μg/ml). Thus, apoptosis would not occur while promoting the increased expression of osteogenic-associated factors, such as runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN), bone sialoprotein (BSP), and collagen type 1 (COL-1). A safe concentration of particles can stimulate cell alkaline phosphatase and matrix calcium salt deposition. The dual antibacterial effect from the direct contact killing of QAS and the sustained release of Ag nanoparticles, along with the Ag-promoted osteogenic differentiation, had been verified and utilized in Ag@QHMS. This system demonstrates the potential for utilizing pluripotent biomaterials to treat complex lesions.

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Chen, Ning, Chunyu Zhang, Xiaoyan Dong e Yan Sun. "Fabrication and characterization of epoxylated zwitterionic copolymer-grafted silica nanoparticle as a new support for lipase immobilization". Chinese Journal of Chemical Engineering 28, n. 4 (aprile 2020): 1129–35. http://dx.doi.org/10.1016/j.cjche.2019.12.006.

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Tran, Vu-Long, Vivek Thakare, Marco Natuzzi, Mathieu Moreau, Alexandra Oudot, Jean-Marc Vrigneaud, Alan Courteau et al. "Functionalization of Gadolinium Chelates Silica Nanoparticle through Silane Chemistry for Simultaneous MRI/64Cu PET Imaging". Contrast Media & Molecular Imaging 2018 (1 novembre 2018): 1–10. http://dx.doi.org/10.1155/2018/7938267.

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Multimodal nanoprobes are highly demanded for biomedical imaging applications to enhance the reliability of the diagnostic results. Among different types of nano-objects, ultrasmall silica gadolinium nanoparticle (SiGdNP) appears as a safe, effective, and versatile platform for this purpose. In this study, a new method to functionalize SiGdNP based on silane chemistry has been reported. Two types of chelating silanes (APTES-DOTAGA and APTES-NODAGA) have been synthesized and grafted on SiGdNP by a simple one-step protocol. This functionalization strategy requires no other reactants or catalyzers and does not compromise the ultrasmall size of the particles. NODAGA-functionalized particle has been labeled with 64Cu isotope and injected intravenously to mice bearing TS/A carcinoma tumor for biodistribution study to demonstrate its potential as a bimodal MRI/PET imaging agent. A fully integrated MRI/PET system was used to simultaneously monitor the distribution of the particle. The results showed that the functionalized particle maintained properties of a renal clearable NP which could rapidly escape through kidneys and had low retention in other organs, especially liver, even though its accumulation in the tumor was modest.

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Wu, Jian-Hong, Yong Zhao, Ting Li, Cong Xu, Kuang Xiao, Yu-Qi Feng e Lin Guo. "The use of liquid phase deposition prepared phosphonate grafted silica nanoparticle-deposited capillaries in the enrichment of phosphopeptides". Journal of Separation Science 33, n. 12 (12 maggio 2010): 1806–15. http://dx.doi.org/10.1002/jssc.201000029.

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Pillai, Prathibha, Rohit Kumar Saw, Ranvijay Singh, Eswaran Padmanabhan e Ajay Mandal. "Effect of synthesized lysine-grafted silica nanoparticle on surfactant stabilized O/W emulsion stability: Application in enhanced oil recovery". Journal of Petroleum Science and Engineering 177 (giugno 2019): 861–71. http://dx.doi.org/10.1016/j.petrol.2019.03.007.

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Beagan, Abeer M., Ahlam A. Alghamdi, Shatha S. Lahmadi, Majed A. Halwani, Mohammed S. Almeataq, Abdulaziz N. Alhazaa, Khalid M. Alotaibi e Abdullah M. Alswieleh. "Folic Acid-Terminated Poly(2-Diethyl Amino Ethyl Methacrylate) Brush-Gated Magnetic Mesoporous Nanoparticles as a Smart Drug Delivery System". Polymers 13, n. 1 (25 dicembre 2020): 59. http://dx.doi.org/10.3390/polym13010059.

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Currently, chemotherapy is an important method for the treatment of various cancers. Nevertheless, it has many limitations, such as poor tumour selectivity and multi-drug resistance. It is necessary to improve this treatment method by incorporating a targeted drug delivery system aimed to reduce side effects and drug resistance. The present work aims to develop pH-sensitive nanocarriers containing magnetic mesoporous silica nanoparticles (MMSNs) coated with pH-responsive polymers for tumour-targeted drug delivery via the folate receptor. 2-Diethyl amino ethyl methacrylate (DEAEMA) was successfully grafted on MMSNs via surface initiated ARGET atom transfer radical polymerization (ATRP), with an average particle size of 180 nm. The end groups of poly (2-(diethylamino)ethyl methacrylate) (PDEAEMA) brushes were converted to amines, followed by a covalent bond with folic acid (FA) as a targeting agent. FA conjugated to the nanoparticle surface was confirmed by X-ray photoelectron spectroscopy (XPS). pH-Responsive behavior of PDEAEMA brushes was investigated by Dynamic Light Scattering (DLS). The nanoparticles average diameters ranged from ca. 350 nm in basic media to ca. 650 in acidic solution. Multifunctional pH-sensitive magnetic mesoporous nanoparticles were loaded with an anti-cancer drug (Doxorubicin) to investigate their capacity and long-circulation time. In a cumulative release pattern, doxorubicin (DOX) release from nano-systems was ca. 20% when the particle exposed to acidic media, compared to ca. 5% in basic media. The nano-systems have excellent biocompatibility and are minimally toxic when exposed to MCF-7, and -MCF-7 ADR cells.

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Ghasemi, Soheila, e Saiede Karim. "Mizoroki–Heck Cross-Coupling Reaction of Haloarenes Mediated by a Well-Controlled Modified Polyacrylamide Brush Grafted Silica/Pd Nanoparticle System". Bulletin of the Chemical Society of Japan 90, n. 5 (15 maggio 2017): 485–90. http://dx.doi.org/10.1246/bcsj.20160374.

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Ghasemi, Soheila, Fatemeh Farjadian e Bahman Tamami. "Biaryl formation via Suzuki and Stille coupling reactions using palladium nanoparticle/polymeric N-heterocyclic carbene grafted silica as recyclable and efficient catalyst". Applied Organometallic Chemistry 30, n. 10 (13 giugno 2016): 818–22. http://dx.doi.org/10.1002/aoc.3508.

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Lee, Sangmi, e KiRyong Ha. "Quantitative Analysis of Grafted Methacrylate Groups by Michael Addition Reaction between Primary and Secondary Amino Groups on the Silica Nanoparticle Surface with 3-(Acryloyloxy)-2-Hydroxypropyl Methacrylate". Polymer Korea 39, n. 2 (25 marzo 2015): 300–310. http://dx.doi.org/10.7317/pk.2015.39.2.300.

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46

Bailly, Bérangère, Anne-Carole Donnenwirth, Christèle Bartholome, Emmanuel Beyou e Elodie Bourgeat-Lami. "Silica-Polystyrene Nanocomposite Particles Synthesized by Nitroxide-Mediated Polymerization and Their Encapsulation through Miniemulsion Polymerization". Journal of Nanomaterials 2006 (2006): 1–10. http://dx.doi.org/10.1155/jnm/2006/76371.

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Polystyrene (PS) chains with molecular weights comprised between 8000 and 64000g⋅mol-1and narrow polydispersities were grown from the surface of silica nanoparticles (Aerosil A200 fumed silica and Stöber silica, resp.) through nitroxide-mediated polymerization (NMP). Alkoxyamine initiators based on N-tert-butyl-1-diethylphosphono-2,2-dimethylpropyl nitroxide (DEPN) and carrying a terminal functional group have been synthesized in situ and grafted to the silica surface. The resulting grafted alkoxyamines have been employed to initiate the growth of polystyrene chains from the inorganic surface. The maximum grafting density of the surface-tethered PS chains was estimated and seemed to be limited by initiator confinement at the interface. Then, the PS-grafted Stöber silica nanoparticles were entrapped inside latex particles via miniemulsion polymerization. Transmission electron microscopy indicated the successful formation of silica-polystyrene core-shell particles.

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Pelto, Jani, Tony Munter, Outi Härkki e Juha Sarlin. "Surface Modification of Nanosilica for PP Composites". Materials Science Forum 714 (marzo 2012): 91–98. http://dx.doi.org/10.4028/www.scientific.net/msf.714.91.

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Due to its high purity, favourable surface chemistry and huge specific surface area, fumed silica nanoparticlesare suitable inorganic nanoscopic templates for organic modification and nanocomposite studies. Polypropylene offers good properties with low or moderate cost for many technical applications, such as for solid dielectrics. Polypropylene and hydrophilic silica nanoparticles have inherently dissimilar surface chemistries and organic modification of the silica is usually needed to achieve good mixing and nanocomposite properties. Thetarget is to study robust grafting methods which can be up-scalable without complicated process steps. In thiswork nanosilica particleshave been modified by grafting to method using equimolar amounts of various chain lengths of vinyl functional polyisobutene (PIB) oligomers (molecular weights 320 g/mol, 920 g/mol and 2300 g/mol, determined by material supplier), further functionalized by epoxidation and subsequent reaction with organosilane.The glass transition temperature, viscoelastic properties and crystallization behaviour of the PP compositeswith PIB grafted silicas (4.5 wt% silica) were altered. Especially the PIB2300 grafted silica composite showed improved low temperature fracture toughness, significantly (14°C) lower glass transition measured by DMA and higher crystallization temperature compared to the pure polypropylene.

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Friedrich, Klaus, Min Zhi Rong, Ming Qiu Zhang e Wen Hong Ruan. "Preparation of Nano-Silica/Polypropylene Composites Using Reactive Compatibilization". Key Engineering Materials 312 (giugno 2006): 229–32. http://dx.doi.org/10.4028/www.scientific.net/kem.312.229.

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Nano-sized silica particles were pre-grafted with poly(glycidyl methacrylate) (PGMA) by solution free-radical polymerization. When these grafted silica nanoparticles were melt compounded with polypropylene (PP), reactive compatibilization effect was perceived due to the chemical bonding between the grafted PGMA and amine functionalized PP, which led to a significant increase of tensile strength and notch impact strength of PP at rather low filler content. Accordingly, compatibility of each kind of the functionalized PP with grafted SiO2 nanoparticles was evaluated through investigating the mechanical properties, crystallization behavior and rheological performance of the composites. The results show that the reactive compatibilization is capable of providing stronger interfacial adhesion.

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Clément, Laura, Arnaud Zenerino, Charlotte Hurel, Sonia Amigoni, Elisabeth Taffin de Givenchy, Frédéric Guittard e Nicolas Marmier. "Toxicity assessment of silica nanoparticles, functionalised silica nanoparticles, and HASE-grafted silica nanoparticles". Science of The Total Environment 450-451 (aprile 2013): 120–28. http://dx.doi.org/10.1016/j.scitotenv.2013.01.042.

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Peng, Ren Gui, Cheng En He, Wei Tang, Yue E. Liu e Ying Kui Yang. "Silica-Polymer Core-Shell Particles for Fabrication of Poly(methyl methacrylate) Composite Materials". Advanced Materials Research 531 (giugno 2012): 153–56. http://dx.doi.org/10.4028/www.scientific.net/amr.531.153.

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Poly(n-butyl acrylate) grafted silica nanoparticles were compounded with poly(methyl methacrylate) to yield silica/polymer composites with the improved dispersion of silica and interfacial adhesion with the matrix, thus showing increases in storage modulus and glass transition temperature.

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