摘要
通过偏光显微镜和 DSC技术 ,较为详细地研究了不同端基及分子量 PEO的结晶行为。当 PEO的分子量大于 60 0 0 g/ mol时 ,分子量对其结晶行为的影响逐渐变得很小 ;当分子量介于 60 0 0 g/ mol～ 2 0 0 0g/ mol时 ,为一临界分子量区 ,分子量变化对其结晶能力有很大的影响。氯乙基酯端基 PEO链的折叠结晶受限较大 ,结晶度损失较大。而且 ,当分子量降至临界分子量区时 ,PEO结晶受限对端基体积更加敏感 ,结晶能力大大降低。羟基端基对结晶熔融焓 (ΔHf)的影响与分子量的大小有强烈的关系。Tm
The crystallization of polymers, which is one of the most important ordering behaviors for polymers, has been an important topic in polymer physics for the past several decades. Chain folding in polymer lamella crystals is the key mechanism, which distinguishes polymer crystallization and morphology from that of small molecules. Most of studies were conducted on low molecular weight poly (ethylene oxide (PEO) fractions to help understand the polymer crystallization. The crystallization behavior of PEO with different end groups and molecular weights were reported. The crystallization ability of PEO studied was characterized with optical microscopy and DSC technologies. The experimental results show that the end goup of ClCH 2COO- can damage the crystallization of PEO more seriously than -OH end group, moreover, the extent of crystallization damage owing to end goup depends heavily on the molecular weight of PEO fractions. When the molecular weight of PEO fractions are higher than 6000 g/mol, the influence of end group on crystallization become very small. But, the end group can heavily decrease the degree of crystallization of PEO fractions, if the molecular weight of PEO decreases from 6000 g/mol to 2000 g/mol.
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
2003年第1期148-151,共4页
Polymer Materials Science & Engineering
关键词
端基
分子量
聚氧乙烯
结晶行为
研究
poly (ethylene oxide)
crystallization
end-group
molecular weight
