Effect of the reactional variables on the synthesis of a functionalized biodegradable polymer: PCL-g-MA

ABSTRACT Poly (ɛ-caprolactone) (PCL) is a biodegradable synthetic thermoplastic that has been the focus of studies on new "green polymers", due mainly to its good mechanical properties, which makes it competitive among other conventional polymers and biopolymers, such as, Poly(lactic acid) (PLA) and Poly(hydroxybutyrene) (PHB). The objective of this work was the grafting of maleic anhydride (MA) reactive groups in PCL for the production of a functional biodegradable polymer. The grafting synthesis of the maleic anhydride in the PCL occurred in an internal lab mixer, using concentrations of 2.5 and 5.0% MA and 0.3 and 0.5% of the dicumyl peroxide initiator (DCP) at two temperatures of process, 110°C and 160°C. The methodology of factorial planning 23 was used to optimize the experiments, as well as to evaluate the efficiency of the reaction conditions employed for PCL functionalization. The results indicated that maleic anhydride was grafted onto PCL using the dicumyl peroxide initiator. The percentage of graphitized maleic anhydride (% gMA) was obtained by titration and confirmed by Fourier Transform Infra-Red (FTIR). Through the obtained results it can be inferred that higher content (5.0%) of MA positively favored the grafting. However, over certain amount, a saturation of the system may occur and the tendency is for recombination.

摘要 聚(ε-己内酯)（Poly(ɛ-caprolactone)，PCL）是一种可生物降解的合成热塑性塑料，因具备优异的力学性能，在传统聚合物与聚乳酸（Poly(lactic acid)，PLA）、聚羟基丁酸酯（Poly(hydroxybutyrene)，PHB）等生物聚合物中具备竞争力，因此成为新型“绿色聚合物”相关研究的热点。本研究的目标是将马来酸酐（maleic anhydride，MA）反应性基团接枝至PCL上，以制备功能性可生物降解聚合物。实验通过实验室内部密炼机完成PCL的马来酸酐接枝合成，采用2.5%、5.0%的MA浓度，以及0.3%、0.5%的过氧化二异丙苯（dicumyl peroxide initiator，DCP）引发剂浓度，并设置110℃与160℃两个反应温度。本研究采用2³因子设计法优化实验流程，并评估用于PCL功能化的反应条件的反应效率。结果表明，以过氧化二异丙苯为引发剂可成功将马来酸酐接枝至PCL上。接枝马来酸酐百分比（%gMA）通过滴定法测得，并经傅里叶变换红外光谱（Fourier Transform Infra-Red，FTIR）验证。由实验结果可推断，较高浓度（5.0%）的MA对接枝反应具有积极促进作用；但当浓度超过一定阈值时，体系可能出现饱和，反应倾向于发生重组。