核/壳结构聚合物改性硬质聚氯乙烯的力学性能

Preparation of Acrylic Core/Shell Polymer and Its Application in Toughening Rigid PVC Matrix

采用种子乳液聚合制备了丙烯酸酯核/壳结构聚合物,总转化率超过95%,乳胶粒理论粒径与实测值基本一致,说明聚合体系没有明显的二次成核过程。将其用于硬质聚氯乙烯改性,当加入量为3phr时,就能产生显著的增韧效果,常温缺口冲击强度达到16.51 kJ/cm2,而拉伸强度基本保持不变。扫描电镜分析冲击断口表明,核/壳聚合物已经很好分散到聚氯乙烯基体中,呈网状结构,为明显的韧性断裂过程。该研究有望应用于工业生产。

Poly （ n-butyl acrylate）/poly （ methyl methacrylate） core/shell polymer （ACR） was prepared by semi-continuous emulsion polymerization. The instantaneous conversion is higher than 85 % and overall conversion is over 95 %. Comparison of theoretically calculated particle diameters with those measured experimentally show that the particles have grown without significant secondary nucleation occurring. The TEM analysis verified the morphology and the particle size. When it was used to modify PVC matrix, the PVC/ACR blend occurres brittle-ductile transition with the addition of 3 phr ACR. The Charley impact strength reaches 16.51 kJ/m^2, while the tensile keeps a relative high value （61.37 MPa）. The SEM observation was used to explain the toughening mechanism. The ACR modifier is dispersed homogeneously in the PVC matrix, and the fractured surfaces show the networked structure and ductile deformation. The particle with approximately 180 nm of rubber-phase yields the effective impact absorption while minimizing the loss of tensile properties. This result will be used in the industrial scale in the nearest future.