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利用升温淋洗分级(TREF)和连续自成核退火热分级(SSA)等方法研究了L-丙交酯(LLA)和ε-己内酯(ε-CL)共聚物(PLC)分子链结构的非均匀性.合成了2种不同摩尔比的PLC共聚物,用TREF的方法,将同一个共聚物分级出3个级份.用核磁共振氢谱(1H-NMR)和凝胶渗透色谱(GPC)等方法对每个级份的分子结构进行了表征.结果表明,随着淋洗温度的升高,共聚物级份中的ε-CL单元的含量明显降低,而且级份的数均分子量增大,分子量分布指数降低.在SSA热分级研究中,发现PLC各级份间存在明显的分子链间和分子链内结构上的差异,这种链结构差异使得各个级份表现出不同的熔融行为.
The molecular chain structure of L-lactide (LLA) and ε-caprolactone (ε-CL) copolymer (PLC) was studied by means of temperature rising leaching fractionation (TREF) and continuous self-nucleation annealing heat fractionation (SSA) The two copolymers with different molar ratios were synthesized, and the same copolymer was fractionated into three fractions by the TREF method.H NMR and gel permeation chromatography (1H-NMR) GPC) were used to characterize the molecular structure of each fraction.The results showed that the content of ε-CL units in the copolymer fraction decreased obviously with the increase of the rinsing temperature, and the number average molecular weight Increased, the molecular weight distribution index decreased.In the SSA thermal grading study, we found that there is a significant difference between the molecular chains and the intramolecular chains in PLC grades. The difference in the chain structure makes all the fractions show different melting behavior.