Recyclable biocomposites based on degradable polymer systems and cellulosic plant fibers are attractive in a sustainable society, because of enhanced polymer properties and also from an end-of-life perspective. Improved understanding is required for how the degradable polymer matrix is affected during compounding in addition to effects from the cellulosic fiber structure and its chemical nature. This work reveals that a poly(ε-caprolactone) matrix undergoes localized, heterogeneous polymer degradation in the fiber-matrix interphase region during melt-compounding. The extent of localized degradation correlates with the initial moisture content in the wood cellulose fiber, where moisture content is controlled by different fiber modification methods by PCL-grafting. As an effect, high moisture content results in a destabilized and degraded fiber-matrix interphase. This was found through careful analysis of how the polymer population changed after compounding, using two different methods: molar mass distribution from SEC and end-group concentration from NMR. The results are important not only with regard to fiber/matrix interface compatibility but also to understand fiber modification for improved biocomposites recycling.

中文翻译：

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走向生物复合材料的回收：PCL-纤维素生物复合材料的局部相间降解及其缓解措施。

基于可降解聚合物系统和纤维素植物纤维的可回收生物复合材料在可持续发展社会中具有吸引力，因为它具有增强的聚合物特性，而且从使用寿命的角度来看也是如此。除了纤维素纤维结构及其化学性质的影响外，还需要进一步了解可降解聚合物基质在配混过程中的影响。这项工作表明，聚（ε-己内酯）基体在熔融复合过程中在纤维-基体相间区域经历了局部的异质聚合物降解。局部降解的程度与木材纤维素纤维中的初始水分含量有关，其中水分含量是通过PCL接枝的不同纤维改性方法来控制的。结果，高水分含量会导致纤维-基体间质相不稳定和降解。这是通过使用两种不同的方法仔细分析聚合物在配混后的变化而发现的：来自SEC的摩尔质量分布和来自NMR的端基浓度。结果不仅对于纤维/基质界面的相容性很重要，而且对于理解纤维改性以改善生物复合材料的回收利用也很重要。