齐民
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发表时间:2009-01-01
发表刊物:功能材料
所属单位:化工学院
卷号:40
期号:1
页面范围:123
ISSN号:1001-9731
摘要:Poly(DL-lactide-co-epsilon-caprolactone) copolymers were prepared by
copolymerization of DL-LA and epsilon-CL using nontoxic magnesium
octoate as catalyst in bulk.Microstructure analyses of the resulting
copolymers were performed by means of 13CNMR spectroscopy.Two modes of
transesterification occurred during the copolymerization process and
played an important role in the redistribution of comonomer sequences
toward randomness.The copolymer composition has a profound influence on
the average block length of lactidyl and caproyl units(LeLL and
LeC).Both LeLL and LeC increased as the relative proportions of their
respective monomers increased.The thermal properties and crystallization
of the copolymers were investigated by DSC and XRD.The results showed
that a close relationship between copolymer crystallinity and the length
of the copolymer sequences.All the copolymers exhibited a single Tg.The
experimental Tgs were in agreement with the calculated values from Fox
equation.It can be concluded that the copolymers are random,or comprise
a mixture of compatible block copolymers.
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