PBA／PS核壳聚合物的制备及其与PS共混

Preparation of core-shell structured polymer and its application in toughening polystyrene

采用种子乳液聚合方法制备了丙烯酸丁酯/苯乙烯核壳结构聚合物,研究了不同核壳单体质量比对乳液聚合过程的影响。结果表明,单体的总转化率超过98%;假设乳胶粒为球形生长时,乳胶粒理论粒径与实测值基本一致,说明该聚合体系没有明显的二次成核过程。随着核壳单体质量比的增加,低温区(聚丙烯酸丁酯)的玻璃化转变温度变化不大,而高温区(聚苯乙烯)的玻璃化转变温度呈下降趋势,这说明该核壳结构界面存在明显的过渡层。将该乳液聚合物与聚苯乙烯共混,随着核壳单体质量比的增加,共混物的冲击强度呈先增加后降低的趋势,说明该核壳聚合物对聚苯乙烯的增韧存在最佳条件。

The authors prepared a kind of core-shell structured polymer from n-butyl acrylate and styrene via seed emulsion polymerization, and studied the effect of mass ratio of core to shell monomer on emulsion polymerization process. The result verifies that the total conversion of the monomers exceeds 98%. On the assumption that the latex particles present and grow in the shape of sphere, the theoretical particle diameter of the latexes is consistent with the actually measured value; the fact reveals that there exists no significant secondary nucleation in the polymerization system. As the mass ratio of core to shell monomer rises, no obvious variation in glass transition temperature （Tg） of the low temperature zone [poly（n-butyl acrylate） zone] appears while a declining trend in Ts of high temperature zone （polystyrene zone） occurs. This phenomenon demonstrates the existence of the transition layer formed on the interface of the core-shell structure. When blending the emulsion polymer with polystyrene （PS）, the impact strength of the blending increases at first and decreases with that as the mass ratio of core to shell monomer augments, that means there are optimum conditions suitable for toughening PS with the core-shell structured polymer.