Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macro-monomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxidewith diphenyl methyl potassium as the initiator and acryloyl...Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macro-monomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxidewith diphenyl methyl potassium as the initiator and acryloyl chloride as the reaction termi-nating agent. The polymer was characterized by FTIR and SEC. The emulsifier-free emul-sion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containingvarious concentrations of PEO-A was studied. In all cases stable emulsion coplymerizationsof MMA and BA were obtained. The stabilizing effect was found to be dependent on themolecular weight and the feed amount of the macromonomer.展开更多
The catalytic activities of some heteropolyacids(HPAs) in synthesizing butyl acrylate are reported. It has been demonstrated that 12 tungstophosphoric acid is the most effective catalyst among more than 20 HPA(s...The catalytic activities of some heteropolyacids(HPAs) in synthesizing butyl acrylate are reported. It has been demonstrated that 12 tungstophosphoric acid is the most effective catalyst among more than 20 HPA(salts). Various factors concerned in this reaction have been investigated. The optimum conditions have been found, that is, the molar ratio of alcohol to acid is 1.2∶1.0 , the catalyst concentration 1%(mass fraction), the reaction time 2 h, the temperature 98—124 ℃ and a certain amount of polymerization inhibitor exists.展开更多
Magnesium hydroxide(MH) whiskers were modified via in situ polymerization of n-butyl acrylate and maleic anhydride. Sodium dodecyl sulfonate was used as emulsifier. The modifying effect was evaluated by using contact ...Magnesium hydroxide(MH) whiskers were modified via in situ polymerization of n-butyl acrylate and maleic anhydride. Sodium dodecyl sulfonate was used as emulsifier. The modifying effect was evaluated by using contact angle and activation index. The thermal stability,functional groups, structure, morphology, phase composition and surface element valence of MH whiskers were characterized by thermogravimetry-differential scanning calorimetry(TG-DSC), Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). Results reveal that the contact angle and activation index of modified MH whiskers are 105°and 76.5%, the thermal stability shows little change, and the decomposition temperature ranges between 38 and419 ℃. The copolymer of n-butyl acrylate and maleic anhydride absorbed on the surface of MH whiskers leads to the increased diameter and makes the surface of whiskers be rougher. Furthermore, the absorption of element C on the surface of MH whiskers increases, and the diffraction intensity of C 1 s spectra increases; thus, the compatibility of whiskers in the organic phase can be improved significantly. Lastly, the surface molecular model of MH whiskers modified via in situ copolymerization of n-butyl acrylate and maleic anhydride is established.展开更多
Effects of branches on the crystallization kinetics of polypropylene-g-polystyrene （PP-g-PS） and polypropylene-g- poly（n-butyl acrylate） （PP-g-PnBA） graft copolymers with well-defined molecular structures were s...Effects of branches on the crystallization kinetics of polypropylene-g-polystyrene （PP-g-PS） and polypropylene-g- poly（n-butyl acrylate） （PP-g-PnBA） graft copolymers with well-defined molecular structures were systematically investigated by DSC. The Avrami equation was used to analyze the isothermal crystallization process, while the analysis of nonisothermal crystallization process was based on the Jeziorny-modified Avrami model and Mo model. The kinetics results of isothermal and nonisothermal crystallization verified the peculiar effects of branches on the crystallization process of PP backbones in PP-g-PS and PP-g-PnBA graft copolymers： on one hand, the interaction between branches （n-n interaction between PS branches, or dipole-dipole interaction between PnBA branches） restrained the mobility and reptation ability of the PP backbones, which hindered the crystallization process; on the other hand, the heterogeneous nucleation effect resulting from the branched structure and fluctuation-assisted nucleation mechanism （caused by microphase separation between the PS or PnBA rich phase and the PP rich phase） became more pronounced with increasing branch length, which facilitated the crystallization process.展开更多
文摘Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macro-monomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxidewith diphenyl methyl potassium as the initiator and acryloyl chloride as the reaction termi-nating agent. The polymer was characterized by FTIR and SEC. The emulsifier-free emul-sion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containingvarious concentrations of PEO-A was studied. In all cases stable emulsion coplymerizationsof MMA and BA were obtained. The stabilizing effect was found to be dependent on themolecular weight and the feed amount of the macromonomer.
文摘The catalytic activities of some heteropolyacids(HPAs) in synthesizing butyl acrylate are reported. It has been demonstrated that 12 tungstophosphoric acid is the most effective catalyst among more than 20 HPA(salts). Various factors concerned in this reaction have been investigated. The optimum conditions have been found, that is, the molar ratio of alcohol to acid is 1.2∶1.0 , the catalyst concentration 1%(mass fraction), the reaction time 2 h, the temperature 98—124 ℃ and a certain amount of polymerization inhibitor exists.
基金financially supported by the National Natural Science Foundation of China (No.51272163)
文摘Magnesium hydroxide(MH) whiskers were modified via in situ polymerization of n-butyl acrylate and maleic anhydride. Sodium dodecyl sulfonate was used as emulsifier. The modifying effect was evaluated by using contact angle and activation index. The thermal stability,functional groups, structure, morphology, phase composition and surface element valence of MH whiskers were characterized by thermogravimetry-differential scanning calorimetry(TG-DSC), Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). Results reveal that the contact angle and activation index of modified MH whiskers are 105°and 76.5%, the thermal stability shows little change, and the decomposition temperature ranges between 38 and419 ℃. The copolymer of n-butyl acrylate and maleic anhydride absorbed on the surface of MH whiskers leads to the increased diameter and makes the surface of whiskers be rougher. Furthermore, the absorption of element C on the surface of MH whiskers increases, and the diffraction intensity of C 1 s spectra increases; thus, the compatibility of whiskers in the organic phase can be improved significantly. Lastly, the surface molecular model of MH whiskers modified via in situ copolymerization of n-butyl acrylate and maleic anhydride is established.
基金financially supported by the National Natural Science Foundation of China for the projects(Nos.51233005 and 51073149)
文摘Effects of branches on the crystallization kinetics of polypropylene-g-polystyrene （PP-g-PS） and polypropylene-g- poly（n-butyl acrylate） （PP-g-PnBA） graft copolymers with well-defined molecular structures were systematically investigated by DSC. The Avrami equation was used to analyze the isothermal crystallization process, while the analysis of nonisothermal crystallization process was based on the Jeziorny-modified Avrami model and Mo model. The kinetics results of isothermal and nonisothermal crystallization verified the peculiar effects of branches on the crystallization process of PP backbones in PP-g-PS and PP-g-PnBA graft copolymers： on one hand, the interaction between branches （n-n interaction between PS branches, or dipole-dipole interaction between PnBA branches） restrained the mobility and reptation ability of the PP backbones, which hindered the crystallization process; on the other hand, the heterogeneous nucleation effect resulting from the branched structure and fluctuation-assisted nucleation mechanism （caused by microphase separation between the PS or PnBA rich phase and the PP rich phase） became more pronounced with increasing branch length, which facilitated the crystallization process.
