HDPE/PA6反应增容体系的形态演化与黏弹行为

采用扫描电子显微镜(SEM)与先进流变扩展系统(ARES),研究了马来酸酐接枝高密度聚乙烯(HDPE-g-MAH)对高密度聚乙烯/尼龙6(HDPE/PA6)共混体系形态结构和黏弹行为的影响.发现HDPE-g-MAH的加入可原位生成尼龙6-高密度聚乙烯接枝共聚物(HDPE-g-PA6),使基体与分散相间的相容性显著改善,且随其添加量的增加两者相容性更好,导致HDPE/PA6体系形态结构变化.研究结果表明,由ARES获得的体系黏弹行为参数随HDPE-g-MAH含量的变化可与由SEM所观察到的微观形貌演化很好关联,动态流变学方法可敏感表征增容剂的加入所引起的HDPE/PA6界面性质变化,且能够反映分子链间相互作用的变化及由此导致的分散相颗粒网络的形成.

MORPHOLOGICAL EVOLUTION AND VISCOELASTIC BEHAVIOR OF COMPATIBILIZED HDPE/PA6 BLENDS

Morphologies and viscoelastic behavior of high density polyethylene/nylon 6(HDPE/PA6) blends compatibilized by maleic anhydride grafted high density polyethylene(HDPE-g-MAH) were studied through observation of scanning electron microscope(SEM) and dynamic rheological testing.It is found that HDPE-g-MAH can efficiently enhance the compatibility between PA6 and HDPE and improve the dispersion of PA6 and the interfacial state of phases due to in situ forming of graft copolymer(HDPE-g-PA6).Such improvement appears more obviously with the increasing of HDPE-g-MAH content when the concentration of HDPE-g-MAH is below 20 wt%.Hence,change of HDPE-g-PA6 amount also results in corresponding variations of linear viscoelastic behavior for the blends.The zero shear viscosity of blends increases with the addition of HDPE-g-MAH and approaches invariablenes with 20 wt% HDPE-g-MAH.At low frequency region the dependence of storage modulus on frequency for the blends tends to be weakened with the increase of HDPE-g-MAH concentration and begins to show "second plateau" with 10 wt% HDPE-g-MAH.These phenomena reflect macromolecular-chains entanglement enhancement due to HDPE-g-PA6 forming.Both changes in morphologies and viscoelastic behavior for blends are ascribed to formation of HDPE-g-PA6.Compared with SEM observation,dynamic rheological testing gives much information about interface and interaction between macromolecular-chains.It is suggested that structure evolution with increase of HDPE-g-MAH content for HDPE/PA6 blends can be characterized preferably by using dynamic rheological measurements.