不同高黏HDPE在聚丙烯中相分布及其光学性能研究

Study on the Phase Distribution and Optical Properties of Different High-viscosity HDPE in Polypropylene

采用双螺杆挤出机进行混合加工,以无规共聚聚丙烯(PP)为基体树脂,高黏度高密度聚乙烯(HDPE)为分散相,研究不同高黏HDPE与PP的不相容体系中的"海岛结构",从相态之间的微观相畴尺寸大小和分布来探索与光学性能的关系,尤其是其膜材的消光性能。研究发现,同样高黏度HDPE,即使物性差异较小,相分散和相畴分布等均有明显差异。高黏度、低组分的HDPE在合金材料中为"岛相",在消光膜中起到光的散射核心作用。通过挤出流延机将各HDPE/PP合金材料制成厚度为35μm的薄膜后对膜进行测试,雾度值(HAZE)大小顺序为HDPE-4/PP>HDPE-1/PP>HDPE-3/PP>HDPE-2/PP,对应的散射因子(DIF)大小顺序与雾度值(HAZE)保持一致。这是因为当可见光射入薄膜材料,光线遇到海岛结构中的岛相HDPE,因为高结晶度及其相畴尺寸分布使光发生散射。"海岛结构"中岛相越规整,相畴大小均匀且颗粒感强,相对应的雾度值、散射因子和膜面的均匀性明显更高,这为高端消光薄膜材料体系和流延膜制备指明了调控方向。本材料体系在流延膜厚度为35μm时,透光率超过93%,其雾度值可以达到95%以上。

A twin-screw extruder is used for mixing and processing,random copolymer polypropylene(PP)is used as the matrix resin,and high-viscosity high-density polyethylene(HDPE)is used as the dispersed phase to study the incompatible systems of different high-viscosity HDPE and PP.The"sea-island structure"explores the relationship with optical properties from the size and distribution of the microscopic domains between phases,especially the extinction properties of the film.The study found that the same high-viscosity HDPE,even if the difference in physical properties is small,there are significant differences in phase dispersion and domain distribution.High-viscosity,low-component HDPE is an"island phase"in the alloy material,and plays a core role in light scattering in the matting film.After each HDPE/PP alloy material is made into a film with a thickness of 35μm by an extrusion casting machine,the film is tested.The order of the haze value(HAZE)is HDPE-4/PP>HDPE-1/PP>HDPE-3/PP>HDPE-2/PP,the order of the corresponding scattering factor(DIF)is consistent with the haze value(HAZE).This is because when visible light enters the film material,the light encounters the island phase HDPE in the sea-island structure,because the high crystallinity and its domain size distribution cause the light to scatter.In the"sea-island structure",the island phase is more regular,the domain size is uniform and the graininess is strong,and the corresponding haze value,scattering factor and uniformity of the film surface are significantly higher.This is the preparation of high-end matting film material systems and cast films Pointed out the direction of regulation.When the thickness of the cast film of this material system is 35μm,the light transmittance exceeds 93%,and the haze value can reach more than 95%.