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Poly(L?lactic acid)-block-poly(butylene succinate-co-butylene adipate) Multiblock Copolymers: From Synthesis to Thermo-Mechanical Properties  
Poly(L?lactic acid)-block-poly(butylene succinate-co-butylene adipate) Multiblock Copolymers: From Synthesis to Thermo-Mechanical Properties
资料类型: PDF文件
关键词: biodegradable  multi-block  copolymer  chain  extension  chain  coupling  
资料大小: 1952k
所属学科: 高分子化学
来源: 来源网络
简介:
Multiblock copolymers poly(L-lactic acid)-block-poly(butylene succinate-co-butylene adipate)s (abbr. P(LLA-mb- BSA)s) are synthesized via a polycondensation/chain extension/coupling method using binary chain extenders. A poly(L-lacticacid) (PLLA) prepolymer synthesized via direct melt polycondensation of L-lactic acid is rapidly chain extended with a bis (2-oxazoline) to form hydroxyl terminated dimer, and the dimer is then chain extended/coupled with a hydroxyl terminatedpoly(butylene succinate-co-butylene adipate) (PBSA) prepolymer by a diisocyanate. The microstructure is characterized withGPC, 1H NMR and FTIR, and the thermo-mechanical properties are investigated with DSC, TGA, DMA, tensile, and impacttesting. In the copolymers, the PLLA hard segments are crystallizable and the PBSA soft segments are amorphous, and onlymelting of PLLA segment was detected. Two independent glass transitions corresponding to both segments are observed,suggesting incompatibility between the two kinds of segments. The tensile modulus and strength decrease while the elongation atbreak and impact strength increase with increasing the weight percentage of PBSA segment (?w,PBSA). The mechanical propertiescan be tuned in wide range by ?w,PBSA, from toughened thermoplastics with excellent tensile modulus, strength and impactstrength to thermoplastic elastomers with high elongation at break
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