The internal plasticization of cellulose acetate (CA) was achieved by grafting with ε-caprolactone (CL) via reactive processing. The effect of varying concentrations of tin(II) bis(2-ethylhexanoate) [Sn(Oct)₂] and iron(III) acetylacetonate [Fe(Acac)₃] catalysts on the ring-opening polymerization (ROP) of CL were compared with each other. The analysis of processing parameters, weight loss measurements, FTIR, and ¹H NMR spectrometry all showed improving grafting efficiency with increasing concentrations of both catalysts. Processing conditions also significantly affect the characteristics of the final product. The resulting structure, i.e., relatively long (2200 g/mol) PCL chains grafted to a small number (1–3%) of CA hydroxyls, promotes thermoplasticity, thus enabling processing in the melt state, while also preserving the biodegradable character of cellulose acetate. The performances of the two catalysts were found to be very similar, which suggests that conventional Sn(Oct)₂ could be substituted with the less toxic Fe(Acac)₃ for the graft ROP of caprolactone.

Graphic abstract

中文翻译：

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醋酸纤维素反应制备ε-己内酯的开环聚合

醋酸纤维素（CA）的内部增塑是通过反应性加工接枝ε-己内酯（CL）来实现的。比较了不同浓度的双(2-乙基己酸)锡(II) [Sn(Oct) ₂ ] 和乙酰丙酮酸铁(III) [Fe(Acac) ₃ ] 催化剂对CL 开环聚合(ROP) 的影响彼此。加工参数分析、重量损失测量、FTIR 和¹1H NMR 光谱均显示随着两种催化剂浓度的增加，接枝效率提高。加工条件也显着影响最终产品的特性。由此产生的结构，即接枝到少量 (1-3%) CA 羟基的相对长 (2200 g/mol) PCL 链促进了热塑性，从而能够在熔融状态下加工，同时还保留了纤维素的可生物降解特性醋酸盐。发现两种催化剂的性能非常相似，这表明传统的 Sn(Oct) ₂可以用毒性较小的 Fe(Acac) ₃代替，用于己内酯的接枝 ROP。

图形摘要