Improvement of heat stability of poly(l-lactic acid) by radiation-induced crosslinking

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• 作者：Hiroshi Mitomo ; Ayako Kaneda ; Tran Minh Quynh ; Naotsugu Nagasawa and Fumio Yoshii
• 关键词：Poly(l-lactic acid) ; Radiation-induced crosslinking ; Thermomechanical analysis
• 刊名：Polymer
• 出版年：2005
• 出版时间：2005
• 年：2005
• 卷：46
• 期：13
• 页码：4695-4703
• 全文大小：244 K

文摘

Poly(l-lactic acid) (PLLA) has poor heat stability above its glass transition temperature (T_g60 °C). To improve its softing above T_g, PLLA was mixed with small amount of crosslinking agents and irradiated with various irradiation doses to introduce crosslinking between polymer chains. The most effective agent for radiation crosslinking was triallyl isocyanurate (TAIC). For melt-quenched PLLA, it was found that the most optimal conditions to introduce crosslinking were around 3 % of TAIC and the irradiation dose of 50 kGy. The typically crosslinked PLLA showed very low crystallinity because of wide formation of molecular chain network that inhibited molecular motion for crystallization. Notable heat stability above T_g was given by annealing of PLLA samples. Enzymatic degradation of PLLA was retarded with introduction of crosslinks.