Herein, acrylonitrile-styrene-acrylate copolymer (ASA) particles with different microstructure were synthesized by emulsion polymerization and then used for toughening poly(styrene-co-acrylonitrile) (SAN) resin. The structure of ASA particles was confirmed by FTIR. TEM results demonstrated that the particles with different morphologies of multilobe shape, complete core-shell and dumbbell shape were obtained depending on the cross-linker amount. It was found that the toughening efficiency reached the highest when the ASA particles had complete core-shell structure and the shell composition was close to that of the SAN matrix. It was ascribed to the fact that the complete shell layer and similar shell composition provided sufficient interfacial adhesion and transferred stress to induce larger matrix deformation, so that the notched impact strength increased accordingly. Moreover, the notched impact strength of SAN/ASA blend was improved without significantly sacrificing tensile strength when adding 30 wt% ASA particles with the size of around 400 nm. SEM results of the impact-fractured surfaces revealed that irregular fluctuation and numerous microvoids occurred. It was deduced that the toughening mechanism was attributed to the crazings and cavitation of particles. Therefore, this study paved a way of toughening the resin by adjusting the microstructure of the particles including morphology, composition, and size.

中文翻译：

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不同微观结构的丙烯腈-苯乙烯-丙烯酸酯颗粒提高聚（苯乙烯-共-丙烯腈）树脂的韧性

在此，通过乳液聚合合成了具有不同微观结构的丙烯腈-苯乙烯-丙烯酸酯共聚物（ASA）颗粒，然后将其用于增韧聚（苯乙烯-共聚物）。-丙烯腈）（SAN）树脂。ASA颗粒的结构通过FTIR确认。透射电镜结果表明，根据交联剂的用量，可以得到多叶形、完整核壳形和哑铃形等不同形态的颗粒。发现当ASA颗粒具有完整的核壳结构且壳组成接近SAN基体时，增韧效率达到最高。这归因于完整的壳层和相似的壳组成提供了足够的界面粘附和转移应力，从而导致更大的基体变形，从而使缺口冲击强度相应增加。而且，当添加 30 wt% 大小约为 400 nm 的 ASA 颗粒时，SAN/ASA 共混物的缺口冲击强度得到改善，而拉伸强度没有显着牺牲。冲击断裂表面的 SEM 结果显示发生了不规则的波动和大量的微孔洞。据推断，增韧机制归因于颗粒的裂纹和空化。因此，本研究为通过调整颗粒的微观结构（包括形态、组成和尺寸）来增韧树脂铺平了道路。