Reactive functionalization of poly(lactic acid), PLA: Effects of the reactive modifier, initiator and processing conditions on the final grafted maleic anhydride content and molecular weight of PLA

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• 作者：Sukeewan Detyothin ; Susan E.M. Selke ; Ramani Narayan ; Maria Rubino ; Rafael Auras
• 关键词：Maleic anhydride ; Reactive extrusion ; Grafting ; Response surface methodology ; Peroxides ; Maleation
• 刊名：Polymer Degradation and Stability
• 出版年：December, 2013
• 年：2013
• 卷：98
• 期：12
• 页码：2697-2708
• 全文大小：2026 K

文摘

A response surface methodology (RSM) design was used to analyze the effects of maleic anhydride (MA) and 2,5-bis(tert-butylperoxy)-2,5-dimethyl hexane (Luperox or L101) content, and TSE screw speed on the degree of grafted MA (MA_g) and number average molecular weight (M_n) of maleated PLA (PLA-g-MA), which can be used as a reactive compatibilizer in production of PLA blends with various components. PLA-g-MA's FTIR peaks indicated that MA was grafted onto the PLA backbone and oligomeric MA was also present. A maximum of 0.52聽wt% MA_g determined by titration was achieved at the expense of a 50% reduction of M_n and an increase in the polydispersity index to around 2.0. Generally, increasing L101 increased the degree of grafting and decreased M_n. L101 and MA_g had a large effect on the stability of PLA-g-MA's M_n during storage. Nominally, amounts of MA equal to 4.5聽wt%, L101 between 0.45 and 0.65聽wt%, and screw speed of 20聽rpm provided the optimal conditions for grafting MA onto PLA.