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作 者:罗军[1] 林卓立[1] 谭松巍[1,2] 陈正坚[1] 袁方[1] 梁岳龙[3] 林辉[3] 王红军[1] 柳定荣[1] 涂克华[1] 蒋洪亮[1] 余赋生[4] 王利群[1]
机构地区:[1]浙江大学高分子科学与工程学系高分子合成与功能构造教育部重点实验室,杭州3100272 [2]华中科技大学同济药学院国家纳米药物工程技术研究中心,武汉430030 [3]浙江大学医学院附属邵逸夫医院普外二科,杭州310016 [4]中国科学院长春应用化学研究所,长春130022
出 处:《高分子学报》2013年第2期263-269,共7页Acta Polymerica Sinica
基 金:国家自然科学基金(基金号21074112)资助项目
摘 要: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.Molecular chain heterogeneity of the copolymer of L-lactide and ε-caprolactone (PLC) was investigated using the preparative temperature rising elution fractionation (TREF) technique and successive self-nucleation/annealing (SSA) thermal fractionation. Two PLC samples with ε-caprolactone compositions of 5 mol% and 10 mol% were prepared and fraetionated by using TREF. For both samples,three fractions were collected and characterized with nuclear magnetic resonance spectroscopy (1H-NMR) and gel permeation chromatography (GPC). The 1H-NMR results showed that there exists obvious differences in the caproyl content among the fractions. It was also found, with GPC method, that for the fraction of higher elution temperature,the number average molecular weight (M) is higher and the distribution is narrower. The data obtained suggest that the fractionation is mainly the result of the difference of the chain tacticity. The chain heterogeneity of TREF fractions was further analyzed with SSA thermal fractionation. The first Ts to be used in the SSA method was carefully chosen in Domain II for all fractions. After SSA treatment, the appearance of multiple melting behavior for each fraction indicates that a heterogeneous intramolecular distribution of defects still exsits in the chains of fraetionated sample. On the other hand,the intermolecular heterogeneity is evident in the different melting ranges of each fraction.
关 键 词:共聚物 非均匀性 升温淋洗分级 连续自成核退火热分级
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