聚乙烯伸直链晶体的调制式DSC研究  

STUDY ON EXTENDED CHAIN CRYSTALS OF POLYETHYLENE VIA MODULATED DIFFERENTIAL SCANNING CALORIMETER

作　　者：孔杰[1] 范晓东[1] 解云川[1] 乔文强[1] 

机构地区：[1]西北工业大学理学院应用化学系,陕西西安710072

出　　处：《高分子材料科学与工程》2004年第5期178-181,共4页Polymer Materials Science & Engineering

基　　金：国防军工计量"十五"重点项目(61005217)

摘　　要：采用调制式DSC、WAXD、POM和SEM研究了高压结晶聚乙烯伸直链晶体的可逆和不可逆热流的变化特点及其与结晶度的关系。结果表明,高压下聚乙烯结晶生成了高熔点、高结晶度的伸直链晶体;常压结晶聚乙烯晶体的不可逆热流有升温过程中部分结构单元的重结晶放热行为;而高压结晶聚乙烯晶体的不可逆热流中无重结晶放热行为。高压结晶聚乙烯晶体的不可逆热焓值远高于常压结晶聚乙烯晶体,反映了高压下结晶的聚乙烯伸直链晶体在常压下熔融的不可逆性。两种结晶方式聚乙烯结晶度的差别的主要因素是与动力学效应有关的不可逆热流。The DSC and MDSC data show that polyethylene crystallized under high pressure of 640 MPa has the crystallinity of (89.11%) with melting point of (143.4) ℃. The POM and SEM photographs further indicate that the thickness of ECC is 200 nm^280 nm. Compared to FCC, there is no recrystallization exothermic peak in the nonreversing thermograph of ECC, which suggests that there exist the perfect crystals of ECC crystallized out from he hexagonal region. The value of nonreversing endothermic enthalpy of ECC is lager than that of FCC. This clearly indicates that the melting of perfect crystals of ECC is nonreversible under ambient conditions.

关 键 词：聚乙烯 伸直链晶体 调制式DSC 高压结晶 不可逆热流 结晶度 偏光显微镜 扫描电镜 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业]