Adopting N,N′-methylene-bis(acrylamide) (MBA) and inorganic clay (hectorite) as chemical and physical cross-linking agent, respectively, a series temperature sensitive microgels, based on N-isopropylacrylamide (NIPAM...Adopting N,N′-methylene-bis(acrylamide) (MBA) and inorganic clay (hectorite) as chemical and physical cross-linking agent, respectively, a series temperature sensitive microgels, based on N-isopropylacrylamide (NIPAM) as a main monomer and tert-butyl acrylate (tBA) as a comonomer were synthesized by surfactant-free emulsion polymerization(SFEP). The microgel particle size and morphology was investigated by means of Atomic Force Microscope (AFM). The surface tension of latex particles was measured by OCA 40 Micro Video based contact angle measuring device. The results showed that the particle size of the microgels with clay as cross-linker was smaller than that using MBA as chemical cross-linker, but exterior morphology of physical microgels is not as clean and neat as chemical microgels. In general, surface tension decreases with increasing hydrophobic tBA content. These smart microgels varied with temperature have the potential applications in the field of drug delivery and intelligent gel fiber.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
A novel surface modifying agent and internal compatilizer of inorganic and macromolecule composite materials,P(St/MAH/BA)terpolymer,was synthesized in butanone by solution polymerization method using styrene(St),malei...A novel surface modifying agent and internal compatilizer of inorganic and macromolecule composite materials,P(St/MAH/BA)terpolymer,was synthesized in butanone by solution polymerization method using styrene(St),maleic anhydride(MAH),and butyl acrylate(BA)as monomers and azobisisobutyronitrile(AIBN)as an initiator.Some affecting factors on terpolymers yields such as polymerization time,reaction temperature,solvent volume,initiator content,and reactants ratios were studied.Furthermore,the structure and thermal properties of terpolymers were primarily characterized and determined by Fourier Transform Infrared Spectroscopy(FTIR),nuclear magnetic resonance(NMR),thermogravimetric analysis(TGA),and gel permeation chromatography(GPC).The results indicate that the terpolymers are random polymers and the yields are low,but the thermal decomposed temperature of terpolymers P(St/MAH/BA)is around 220 ℃ and the average molecular weights(Mw)achieve 1.189×105 g·mol-1.展开更多
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
P(BA-GMA)(PBG), having various molecular weights, was synthesized by in situ polymerization of butyl acrylate(BA) and glycidyl methacrylate(GMA), and further used as a modifier to improve the comprehensive pro...P(BA-GMA)(PBG), having various molecular weights, was synthesized by in situ polymerization of butyl acrylate(BA) and glycidyl methacrylate(GMA), and further used as a modifier to improve the comprehensive properties of the epoxy curing system. The copolymers were characterized by gel permeation chromatography(GPC). The effects of various molecular weights of copolymers on the mechanical properties, thermal performance, and phase behavior of the curing system were carefully evaluated. The experimental results of differential scanning calorimetry(DSC) and dynamic mechanical analysis(DMA) showed that glass transition temperature decreased and the tan δ peak shifted to a lower temperature with decreasing molecular weight of copolymer. Mechanical properties analysis of curing films showed that the impact strength and fracture toughness increased significantly upon the addition of PBG, indicating good toughness of the modified epoxy resins. From scanning electron microscopy(SEM) studies of the fracture surfaces of ER/PBG systems, the fracture behavior of epoxy matrix was changed from brittleness to toughness.展开更多
The morphological evolution of the latex particles obtained by VAc/BA two stage emulsion polymerization was studied. The designs of two group experiments were as follows:VAc as seed , BA was added in starved or overfl...The morphological evolution of the latex particles obtained by VAc/BA two stage emulsion polymerization was studied. The designs of two group experiments were as follows:VAc as seed , BA was added in starved or overflown condition. The inverted core shell composite latex particles, with PVAc as shell and PBA as core, were found in overflown condition, however, the core shell composite latex particles, with PVAc as core and PBA as shell were found in starved condition. When the core shell composite latex particles in different time in starved condition was kept to reaction end, the morphology of the latex particles inverted. Comparing with the previous work in literature, this paper can provide better and more complete understanding about the morphological evolution of the latex particles in the process of seeded emulsion polymerization of VAc/BA. The photos of TEM of morphology of the latex particles in the process under two conditions and temperature being kept constant were obtained. From viscosity,the existed paradoxical views about the morphology of the latex particles on VAc/BA can be explained in a better and more complete way.展开更多
采用气-固相搅拌式方法,氯气作为引发剂,在加热的情况下合成了聚氯乙烯(PVC)、丙烯酸丁酯(BA)的氯化原位接枝共聚产物(CPVC-g-BA)。用IR、1H-RNM等分析手段研究了PVC氯化原位接枝BA反应的可行性,以GPC等数据讨论了接枝共聚物的结构,并...采用气-固相搅拌式方法,氯气作为引发剂,在加热的情况下合成了聚氯乙烯(PVC)、丙烯酸丁酯(BA)的氯化原位接枝共聚产物(CPVC-g-BA)。用IR、1H-RNM等分析手段研究了PVC氯化原位接枝BA反应的可行性,以GPC等数据讨论了接枝共聚物的结构,并考察了反应温度、反应时间、单体用量对产物接枝率的影响:当加入20份BA,反应温度为120℃时,反应100 m in,接枝率达1.07%。展开更多
基金Supported by the Major Project of Science and Technology Research of the Educational Ministry of China (No.105077) and DoctorateInnovation Foundation of Donghua University(No.106 06 001900611)
文摘Adopting N,N′-methylene-bis(acrylamide) (MBA) and inorganic clay (hectorite) as chemical and physical cross-linking agent, respectively, a series temperature sensitive microgels, based on N-isopropylacrylamide (NIPAM) as a main monomer and tert-butyl acrylate (tBA) as a comonomer were synthesized by surfactant-free emulsion polymerization(SFEP). The microgel particle size and morphology was investigated by means of Atomic Force Microscope (AFM). The surface tension of latex particles was measured by OCA 40 Micro Video based contact angle measuring device. The results showed that the particle size of the microgels with clay as cross-linker was smaller than that using MBA as chemical cross-linker, but exterior morphology of physical microgels is not as clean and neat as chemical microgels. In general, surface tension decreases with increasing hydrophobic tBA content. These smart microgels varied with temperature have the potential applications in the field of drug delivery and intelligent gel fiber.
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Nano Project Foundation of Shanghai Technology Committee,China(No.0652nm039)Shanghai Leading Academic Discipline Project,China(No.B502)Shanghai Key Laboratory Proejct,China(No.08DZ2230500)
文摘A novel surface modifying agent and internal compatilizer of inorganic and macromolecule composite materials,P(St/MAH/BA)terpolymer,was synthesized in butanone by solution polymerization method using styrene(St),maleic anhydride(MAH),and butyl acrylate(BA)as monomers and azobisisobutyronitrile(AIBN)as an initiator.Some affecting factors on terpolymers yields such as polymerization time,reaction temperature,solvent volume,initiator content,and reactants ratios were studied.Furthermore,the structure and thermal properties of terpolymers were primarily characterized and determined by Fourier Transform Infrared Spectroscopy(FTIR),nuclear magnetic resonance(NMR),thermogravimetric analysis(TGA),and gel permeation chromatography(GPC).The results indicate that the terpolymers are random polymers and the yields are low,but the thermal decomposed temperature of terpolymers P(St/MAH/BA)is around 220 ℃ and the average molecular weights(Mw)achieve 1.189×105 g·mol-1.
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.
基金Funded by the National Natural Science Foundation of China(51373129)the Fundamental Research Funds for the Central University(WUT:2013-IV-011)
文摘P(BA-GMA)(PBG), having various molecular weights, was synthesized by in situ polymerization of butyl acrylate(BA) and glycidyl methacrylate(GMA), and further used as a modifier to improve the comprehensive properties of the epoxy curing system. The copolymers were characterized by gel permeation chromatography(GPC). The effects of various molecular weights of copolymers on the mechanical properties, thermal performance, and phase behavior of the curing system were carefully evaluated. The experimental results of differential scanning calorimetry(DSC) and dynamic mechanical analysis(DMA) showed that glass transition temperature decreased and the tan δ peak shifted to a lower temperature with decreasing molecular weight of copolymer. Mechanical properties analysis of curing films showed that the impact strength and fracture toughness increased significantly upon the addition of PBG, indicating good toughness of the modified epoxy resins. From scanning electron microscopy(SEM) studies of the fracture surfaces of ER/PBG systems, the fracture behavior of epoxy matrix was changed from brittleness to toughness.
文摘The morphological evolution of the latex particles obtained by VAc/BA two stage emulsion polymerization was studied. The designs of two group experiments were as follows:VAc as seed , BA was added in starved or overflown condition. The inverted core shell composite latex particles, with PVAc as shell and PBA as core, were found in overflown condition, however, the core shell composite latex particles, with PVAc as core and PBA as shell were found in starved condition. When the core shell composite latex particles in different time in starved condition was kept to reaction end, the morphology of the latex particles inverted. Comparing with the previous work in literature, this paper can provide better and more complete understanding about the morphological evolution of the latex particles in the process of seeded emulsion polymerization of VAc/BA. The photos of TEM of morphology of the latex particles in the process under two conditions and temperature being kept constant were obtained. From viscosity,the existed paradoxical views about the morphology of the latex particles on VAc/BA can be explained in a better and more complete way.
文摘采用气-固相搅拌式方法,氯气作为引发剂,在加热的情况下合成了聚氯乙烯(PVC)、丙烯酸丁酯(BA)的氯化原位接枝共聚产物(CPVC-g-BA)。用IR、1H-RNM等分析手段研究了PVC氯化原位接枝BA反应的可行性,以GPC等数据讨论了接枝共聚物的结构,并考察了反应温度、反应时间、单体用量对产物接枝率的影响:当加入20份BA,反应温度为120℃时,反应100 m in,接枝率达1.07%。