结晶聚合物品相相容性的研究

STUDY ON THE CRYSTALLINE PHASE COMPATIBILITY OF POLYMERS

通过ＤＳＣ、Ｘ－射线衍射、红外光谱及拉伸试验研究了ＨＤＰＥ与ＬＬＤＰＥ、ＨＤＰＥ与ＬＤＰＥ之间的晶相相容性．结果表明，链结构相近的ＨＤＰＥ和ＬＬＤＰＥ的晶相相容性好，能形成共晶；而链结构差异较大的ＨＤＰＥ和ＬＤＰＥ的晶相相容性较差，倾向于分别结晶，但有部分链段被对方的晶区夹持．不论是支化度大的ＬＤＰＥ链段插入以ＨＤＰＥ为主的晶区，还是支化度小的ＨＤＰＥ链段插入以ＬＤＰＥ为主的晶区，都可破坏晶区的规整性．共晶的形成使共混物的熔点、结晶度、晶粒体积等低于两组份的线性加和，而力学性能，尤其是断裂伸长率，则显著提高，呈协同效应．

rystalline phase compatibilities between LLDPE,HDPE and LDPE was studied through DSC,WAXD,IR and tensile test.It is found that LLDPE which has similar chain structure as HDPE,is compatible with HDPE in crystalline state.While LDPE,which has more different chain structure,has poor compatibility with HDPE. HDPE and LDPE chains are inclined to crystallize separately in the existence of partial chain interpenetration Not only LDPE chains which have larger number of branches penetrating into HDPE crystal,but also HDPE chains which have smaller number of branches,penetrating into LDPE crystal,can destroy the regularity of the crystal.The formation of cocrystal make the melting points,crystallinities and crystal dimensions of the blends to be smaller than the linear sum of the two components.Whereas the mechanical propertiesespectially in elongational characteristics improve dramatically.