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Three-dimensional magnetic graphene oxide-magnetite polyvinyl alcohol (3D-GO/PVA/Fe3O4) nanocomposites were successfully prepared. The morphology was characterized and analyzed through scanning electron microscope (SEM) and transmission electron microscope (TEM). The chemical structure and the crystal structure were explored by X-ray powder diffraction (XPS), Fourier transform infrared spectroscopy...
Novel low dielectric constant (low-k) polycarbosilanes with tunable performance are reported in the present work. These well-defined linear-cyclopolycarbosilanes were prepared via the copolymerization of 1,5-hexadiene (1,5-HD) with 3,3-dimethyl-3-sila-1,5-hexadiene (DMSHD) using dimethyl(pyridylamido) hafnium/[Ph3C][B(C6F5)4]/AliBu3 catalytic system. They exhibited excellent dielectric properties...
Ion gels have been obtained by crystallization of polylactide (PLA) in an ionic liquid. The modulus of the resulted ion gels is increased with PLA content in the ionic liquid, whereas ionic conductivity follows an opposite tendency. Isolated spheres, caused by PLA crystallization, are responsible for low modulus in the ion gels with low PLA content. By adding a nucleating agent isolated spheres are...
Activated by [Ph3C][B(C6F5)4], dimethylpyridylamidohafnium complex exhibited high performance in the copolymerization of propylene with 3,3-dimethyl-3-sila-1,5-hexadiene (DMSHD), producing high molecular weight random copolymers without pendent vinyl groups and cross-linking. The effects of the comonomer incorporation on chain microstructure, crystallinity, thermal properties and final mechanical...
A monomer, 2-(isobutyramido)-3-methylbutyl methacrylate (IMMA) was synthesized through a two-step reaction. When a few of IMMA (less than 4 mol%) was copolymerized with N-vinylimidazole (VIm) under free radical polymerization condition, water-soluble P(VIm-co-IMMA) copolymers were obtained. Their structural information was verified and interpreted from 1H NMR, FTIR and GPC. Kinetic analyses from 1...
Currently there is no material clinically available as a long-term vitreous substitute. In this study, an in-situ gelation system based on α-poly(ethylene glycol) methacrylate (α-PEG-MA) and a redox-initiated radical polymerization/crosslinking reaction was evaluated for this purpose. Ammonium persulfate (APS) and N,N,N′,N′-tetramethyl ethylene diamine (TMEDA) were used as initiators. The gelation...
The Sn(Oct) 2 catalyzed polymerization condition of l-lactide (LLA) and racemic lactide (r-LA) using hyperbranched polyethylenimine (PEI) as the macroinitiator was optimized. Multiarm star polymers bearing PEI core and well-controlled poly(l-lactide) (PLLA) or poly(racemic lactide) (PDLLA) arms were successfully prepared under the optimized condition, including: (1) high concentration of Sn(Oct)...
In the Sn(Oct) 2 catalyzed bulk copolymerization of l-lactide (LLA) and a large amount of branching comonomer 2,2-bis(hydroxymethyl)butyric acid (BHB) (LLA/BHB/Sn(Oct) 2 ratio is 5:1:0.05, 135°C), low molecular weight of copolymers with inhomogeneous structure were generated. MALDI-TOF mass spectrum demonstrated that the lower molar mass fraction was dominated with the BHB homo-polycondensation...
Temperature-responsive hollow poly(N-isopropylacrylamide) (PNIPAAm) microspheres were prepared by a two-stage distillation precipitation polymerization to afford a core–shell microspheres with subsequent removal of poly(methacrylic acid) (PMAA) core. PMAA@PNIPAAm core–shell microspheres were synthesized by the second-stage polymerization of NIPAAm in the presence of PMAA as core with N,N′-methylenebisacrylamide...
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