| To improve the dispersion and compatibility of nano-CaCO3, mechanical properties and structure of poly(vinyl chloride)(PVC) nanocomposites, polyacrylate/nano-CaCO3composite particles were successfully prepared. The application of composite particles to toughen Poly(vinyl chloride) nanocomposites was researched in this thesis.The polyacrylate was prepared by the emulsion polymerization. The effects of initiator, temperature, ratio of monomers on the performances of the polymer were investigated. The polyacrylate latex was emulsified, dried and used to tough PVC directly. The effect of cross-linking agent and the latex particle size on PVC toughen were investigated. The polyacrylate latex was coated onto nano-CaCO3particles to prepare the polyacrylate/nano-CaCO3composite modifier. Properties of composite modifier were characterized by TEM, contact angle, FTIR, etc. The effects of composite modifier on the mechanical properties and morphology of PVC were investigated.The result show that latex with different particle size could be gained by changing polymerization condition and the latex particles exhibited core-shell structure. By adding polyacrylate modifier, the notched impact strength of PVC increased. And show better impact strength than CPE at low temperature. With the polyacrylate coated on the surface of nano-CaCO3particles by chemical bonds and physical adsorption, nano-CaC particles got changed from hydrophile to lipophilic.The presence of composite modifier led to an increase in fracture toughness. With polyacrylate content of30phr, the impact strength got a maximum of42.9kJ/m2. The flexure modulus also increased with increasing the composite particles concentration. The fractography of PVC by SEM revealed that the polyacrylate interlayer could effectively induce deformation of the matrix around the nanoparticles to increase energy absorptions for crack initiation and propagation. |
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