EVOH／PE-HD共混相容性研究

使用三种功能化改性的聚乙烯作为相容剂改善EVOH／PE-HD共混体系的相容性，研究了共混体系的热性能和力学性能。SEM表明，相容共混体系中形成了高度分散和牢固的界面结合，二甲苯萃取实验和IR分析证实了相容性的改善来自于EVOH与相容剂之间的化学反应。相容共混体系中EVOH作为分散相时其结晶温度明显降低，结晶速度放慢；共混物中两组分的结晶熔点均低于纯组分。这些均可归因于体系更好的相容性以及强烈的界面作用。相容共混体系的力学性能较之简单共混体系得到明显改善，EVOH为分散相时拉伸强度提高幅度较大(50％)，而在PE-HD为分散相时缺口冲击强度的增幅达到30％。

Compatibility of Poly(ethylene-co-vinyl alcohol) and PE-H D Blends

The thermal and mechanical properties of the blends of poly(ethylene-co-vinyl alcohol)(EVOH)/PE-HD using three types of functionali zed poly ethylenes as the compatibilizers were investigated. SEM showed that finer disper sions and an improved interface adhesion were achieved. Xylene extraction and i nfrared spectra indicated that the modification of the compatibility was result ed from the chemical reaction between EVOH and the compatibilizers during the me lt blending. The crystallization temperature of dispersed EVOH phase, and the me lting points of both EVOH and PE-HD in the compatibilized blending systems were l ower than those in neat resins, which was attributed to the compatibilization an d strong interface interactions. Compared with those in regular blends without c ompatibilizers, the tensile strength increased by 30 % when EVOH was the dispers ed phase, the Charpy notched impact strength increased by 50 % when PE-HD was t he dispersed phase.