With the advent of plastics and the wide range of fillers that are available have made modifications as precise as the tailored resins themselves. To modify the properties of polymer either by using fillers or by prep...With the advent of plastics and the wide range of fillers that are available have made modifications as precise as the tailored resins themselves. To modify the properties of polymer either by using fillers or by preparation of polymer blends gives rise to new materials with tailored properties. More complex, three-component systems, obtained by the addition of polymeric modifier to polymer filled composites may be of interest. Use of Fly ash cenospheres is very attractive because it is inexpensive and its use can reduce the environmental pollution to a significant extent. In the present study, Poly (Methyl Methacrylate) (PMMA)-Fly ash cenospheres composites were prepared using extrusion followed by Injection molding. The effect of matrix modification with Methyl methacrylate– acrylonitrile -butadiene–styrene (MABS) on the performance of PMMA- Fly ash cenospheres compositions was also, studied. It was found that with the addition of Fly ash cenospheres particulate as filler in PMMA showed marginal reduction in Tensile Strength, % Elongation and Impact strength and improvement in Flexural Strength, Heat Deflection Temperature and Vicat Softening Point. Compared with PMMA-cenospheres composites, the notched Impact Strength of the PMMA/MABS/cenospheres composites showed marginal enhancement in values at higher loading of cenospheres. The optimum performances in mechanical and thermal properties were obtained when the ratio of MABS to cenospheres was 1:2.展开更多
Styrene-acrylate latex with high glass transition temperature （T）, low minimum film forming temperature（MFT） and good stability was prepared via core-shell emulsion polymerization. With semicontinuous process, hig...Styrene-acrylate latex with high glass transition temperature （T）, low minimum film forming temperature（MFT） and good stability was prepared via core-shell emulsion polymerization. With semicontinuous process, high conversion rate of monomer and low gel rate were achieved. The weight ratio of core monomer to shell monomer was approximately 1.35. It is found that many factors such as emulsifiers, initiators, reaction temperature, pH value and polymerization technology have influences on the permormance of styrene-acrylate latex. The prepared latex was characterized by TEM and FTIR. The obtained latex with T of 20.57 ℃, MFT or5.0 ℃, and good stability, had good stability of film forming.展开更多
Cationic latexes were prepared through emulsion copolymerization of styrene （St） and butyl acrylate （BA） with a cationic surfactant, cetyl trimethyl ammonium bromide （CTAB）. Latex properties, including particle ...Cationic latexes were prepared through emulsion copolymerization of styrene （St） and butyl acrylate （BA） with a cationic surfactant, cetyl trimethyl ammonium bromide （CTAB）. Latex properties, including particle size, size distribution, （ potential, surface tension and monomer conversion, were determined for latexes prepared with different CTAB amounts. Evolution of these properties during emulsion polymerization was followed in order to understand the mechanism of the particles formation. Results showed that both particle size and 6＂ potential were function of polymerization time and latex solids. Parallel emulsion polymerizations with cationic, anionic charged initiator and charge-free initiators were also carried out, the latex properties were determined at different polymerization time. All these results were attentively interpreted based on the mechanisms of emulsion polymerization, surfactant adsorption and latex particle stabilization.展开更多
文摘With the advent of plastics and the wide range of fillers that are available have made modifications as precise as the tailored resins themselves. To modify the properties of polymer either by using fillers or by preparation of polymer blends gives rise to new materials with tailored properties. More complex, three-component systems, obtained by the addition of polymeric modifier to polymer filled composites may be of interest. Use of Fly ash cenospheres is very attractive because it is inexpensive and its use can reduce the environmental pollution to a significant extent. In the present study, Poly (Methyl Methacrylate) (PMMA)-Fly ash cenospheres composites were prepared using extrusion followed by Injection molding. The effect of matrix modification with Methyl methacrylate– acrylonitrile -butadiene–styrene (MABS) on the performance of PMMA- Fly ash cenospheres compositions was also, studied. It was found that with the addition of Fly ash cenospheres particulate as filler in PMMA showed marginal reduction in Tensile Strength, % Elongation and Impact strength and improvement in Flexural Strength, Heat Deflection Temperature and Vicat Softening Point. Compared with PMMA-cenospheres composites, the notched Impact Strength of the PMMA/MABS/cenospheres composites showed marginal enhancement in values at higher loading of cenospheres. The optimum performances in mechanical and thermal properties were obtained when the ratio of MABS to cenospheres was 1:2.
文摘Styrene-acrylate latex with high glass transition temperature （T）, low minimum film forming temperature（MFT） and good stability was prepared via core-shell emulsion polymerization. With semicontinuous process, high conversion rate of monomer and low gel rate were achieved. The weight ratio of core monomer to shell monomer was approximately 1.35. It is found that many factors such as emulsifiers, initiators, reaction temperature, pH value and polymerization technology have influences on the permormance of styrene-acrylate latex. The prepared latex was characterized by TEM and FTIR. The obtained latex with T of 20.57 ℃, MFT or5.0 ℃, and good stability, had good stability of film forming.
基金supported by the Natural Science Foundation of Shandong Province,China(No.Z2008B07)the National Natural Science Foundation of China(No.20874040)
文摘Cationic latexes were prepared through emulsion copolymerization of styrene （St） and butyl acrylate （BA） with a cationic surfactant, cetyl trimethyl ammonium bromide （CTAB）. Latex properties, including particle size, size distribution, （ potential, surface tension and monomer conversion, were determined for latexes prepared with different CTAB amounts. Evolution of these properties during emulsion polymerization was followed in order to understand the mechanism of the particles formation. Results showed that both particle size and 6＂ potential were function of polymerization time and latex solids. Parallel emulsion polymerizations with cationic, anionic charged initiator and charge-free initiators were also carried out, the latex properties were determined at different polymerization time. All these results were attentively interpreted based on the mechanisms of emulsion polymerization, surfactant adsorption and latex particle stabilization.
