液晶显示已成为目前主流显示技术，其中光扩散板可以雾化光线，保证良好的显示质量。量子点材料具备色彩转换以及提升颜色质量的功能，因此量子点光扩散板是下一代液晶显示的发展方向。近年来以量子点背光为光源的液晶显示技术愈加成熟并正在逐步向市场推广。其中，利用聚合物包覆量子点形成量子点光扩散板可有效降低制造成本，有助于扩大量子点液晶显示的市场份额。分别采用热压以及挤出流延成型方法制备苯乙烯-丙烯腈无规共聚物（SAN）不同含量的聚苯乙烯/苯乙烯-丙烯腈无规共聚物（PS/SAN）复合薄膜，并探讨复合薄膜的微观形貌及对应的力学、光学、氧气阻隔性能。结果表明：SAN质量分数为30%条件下挤出流延膜相较纯聚苯乙烯（PS）薄膜氧气阻隔性提升29%，拉伸强度提升16.6%，透光率大于80%，并具有40%左右的雾度。相比热压成型，挤出流延膜呈现更高的阻隔性能，有望应用于制备PS基量子点扩散板的扩散层。

Liquid crystal display has become the mainstream display technology, in which the light diffusion sheet can haze the light and ensure good display quality. Quantum dot materials have the function of color conversion and improving color quality, so quantum dot light diffusion sheets are the development direction of the next generation of liquid crystal displays. The liquid crystal display technology with quantum dot backlight as the light source has become more mature and is gradually being promoted to the market. The use of polymeric encapsulation method for quantum dot to form quantum dot diffusion sheet can effectively reduce the manufacturing cost and help expand the market share of quantum dot liquid crystal display. In this paper, polystyrene/styrene-acrylonitrile copolymer (PS/SAN) composite films with different contents of styrene-acrylonitrile copolymer (SAN) were prepared by hot pressing and extrusion casting, and the morphology, mechanical, optical and oxygen barrier properties were investigated. The results show that compared with pure (polystyrene) PS film, the oxygen barrier property of the composite film with the SAN mass fraction of 30% prepared by casting is improved by 29%, the tensile strength is improved by 16.6%, the light transmittance is greater than 80% and the haze is at around 40%. Compared with the film prepared by hot pressing, the composite film prepared by casting shows better oxygen barrier property, which is possible to be used to prepare the diffusion layer for PS-based quantum dot diffusion sheet.