| Three kinds of encapsulated polyacrylate/nano-calcium carbonate latices with relatively narrow distribution of particle diameters, which are abbreviated to PBA-PMMA/CaCO3, PMMA/CaCO3 and P(BA-EHA)/CaCO3, were synthesized by emulsion polymerization, respectively. CaCO3 were used as polyacrylate/CaCO3 core, butyl acrylate, 2-ethylhexyl acrylate and methyl methacrylate were employed as comonomers of polyacrylate/CaCO3 shell with 1,4-butanediol diacrylate as cross-linking agent. In the presence of P(BA-EHA)/CaCO3 or PBA-PMMA/CaCO3 or PMMA/CaCO3 latex, three kinds of polyacrylate/CaCO3/PVC composite latex, including P(BA-EHA)/CaCO3/PVC, PBA-PMMA/CaCO3/PVC and PMMA/CaCO3/PVC, were prepared by grafting co-polymerization with vinyl chloride in an autoclave, respectively. The size and distribution of polyacrylate/CaCO3 latex and composite particles were determined by dynamic laser scattering. The morphological structures of latex particles were investigated through TEM. Polyacrylate/CaCO3 latex particles have encapsulation structure obviously. The size distribution of composite latex particles is similar to that of polyacrylate/CaCO3 latex. Their mean particle diameters gradually decrease with amount of polyacrylate/CaCO3 latex and CaCO3/monomers increasing, but the mean particle diameters of the composite latex are much bigger than particle diameters of CaCO3 latex. Molecular weight of PVC composite resin was determined by viscometer.The influence of the effecting factors of the synthesized polyacrylate/CaCO3 on the mechanical properties of PVC and polyacrylate/CaCO3 blend was investigated in detail. The results showed that polyacrylate/CaCO3 is better dispersed in the PVC matrix. The notched impact strength of PVC and polyacrylate/CaCO3 blends is improved obviously. And the tensile strength of the blend has significantly unchanged. The notched impact strength of PVC and PBA-PMMA/CaCO3 blend increased 2 to 3 times that of PVC, when the weight ratio of PVC and PBA-PMMA/CaCO3 is 100/6 and the ratio of CaCO3 and monomers is 35/100. The initial thermolysis temperatures and Vicat softening temperature of the PVC-matrix composites are 25 ℃ and 4.4 ℃ higher over that of pure PVC respectively.The various properties of composite resin and materials made out of it, such as dynamicmechanical property , thermal property , Vicat softening temperature , rheological behavior ,morphological structure and the broken profile of the materials, were determined andcharacterized with the aid of DMA, TA-2000 type thermal analyzer, XWB-300F type detectorof Vicat softening temperature , capillary rheometer, TEM, SEM, respectively. The effects ofamount of P(BA-EHA)/CaCO3 and CaCO3/monomers ratio in it on the mechanical properties ofthe materials were investigated. The notched impact strength and elongation at break of thematerials increase dramatically with increasing CaCO3/monomers ratio, meantime the tensilestrength of the materials somewhat increases. DMA results reveal that the compatibility betweenP(BA-EHA)/CaCO3 and PVC has been well improved. The mechanical loss peak of compositeresin in low temperature region is stronger than that of pure PVC. Further, the maximum valueof the loss peak gradually shifts to higher temperature with increasing CaCO3/monomers ratio.TEM shows that the interface between two phases was indistinct and P(BA-EHA)/CaCO3 phaseis much uniformly dispersed in PVC matrix. SEM shows that the fractured surface of thenotched sample has a very good toughness. Vicat softening temperature of TheP(BA-EHA)/CaCO3/PVC material increases slightly with increasing CaCO3/monomers content.The thermal stability of the composite resin increases. Mobility of composite resin becomesbetter than that of pure PVC due to the addition of P(BA-EHA)/CaCO3. Specially, the notchedimpact strength of the P(BA-EHA)/CaCO3/PVC material with 6.5% P(BA-EHA) was ten timesthat of pure PVC. And its elongation percentage at break was about five times that of PVC.
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