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Degradation of poly( D , L ‐lactic acid)‐ b ‐poly(ethylene glycol) copolymer and poly( L ‐lactic acid) by electron beam irradiation
Author(s) -
Miao Peikai,
Wu Dimeng,
Zeng Ke,
Zhao Chun'e,
Xu Guoliang,
Huang Zhifu,
Yang Gang
Publication year - 2010
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.33174
Subject(s) - ethylene glycol , copolymer , lactic acid , elongation , irradiation , polymer chemistry , ethylene , materials science , degradation (telecommunications) , peg ratio , ultimate tensile strength , bond cleavage , nuclear chemistry , glass transition , polymer , chemistry , chemical engineering , catalysis , organic chemistry , bacteria , composite material , physics , telecommunications , finance , biology , nuclear physics , computer science , engineering , economics , genetics
This article investigated the effects of electron beam (EB) irradiation on poly( D , L ‐lactic acid)‐ b ‐poly(ethylene glycol) copolymer (PLEG) and poly( L ‐lactic acid) (PLLA). The dominant effect of EB irradiation on both PLEG and PLLA was chain scission. With increasing dose, recombination reactions or partial crosslinking of PLEG can occur in addition to chain scission, but there was no obvious crosslinking for PLLA at doses below 200 kGy. The chain scission degree of irradiated PLEG and PLLA was calculated to be 0.213 and 0.403, respectively. The linear relationships were also established between the decrease in molecular weight with increasing dose. Elongation at break of the irradiated PLEG and PLLA decreased significantly, whereas the tensile strength and glass transition temperature of PLLA decreased much more significantly compared with PLEG. The presence of poly(ethylene glycol) (PEG) chain segment in PLEG was the key factor in its greater stability to EB irradiation compared with PLLA. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011