Evidences of Transesterification, Chain Branching and Cross-Linking in a Biopolyester Commercial Blend upon Reaction with Dicumyl Peroxide in the Melt
Evidences of Transesterification, Chain Branching and Cross-Linking in a Biopolyester Commercial Blend upon Reaction with Dicumyl Peroxide in the Melt
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DOI：
10.1002/mame.201400187
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发表时间：
2015-02-01
影响因子：
3.9
通讯作者：
Ciardelli, Francesco
中科院分区：
文献类型：
--
作者：
Signori, Francesca;Boggioni, Alessia;Ciardelli, Francesco
为了通过化学交联调节热机械特性，在布拉本德在过氧化二异丙苯（DCP，0-0.2 wt.-%）存在下加工了基于聚乳酸（PLA）与聚己二酸-对苯二甲酸丁二醇酯（PBAT）（ecovio (R) T2280，BASF）的生物聚酯商业共混物。通过溶解度测试和凝胶含量评估，以及所制备化合物的流变学、机械和分子量分析，研究并合理化了 DCP 添加的影响。此外，详细的 DSC 和 TMDSC 研究提供了对大分子水平上发生的结构修饰的深入了解。我们发现，在 DCP 存在下处理的样品中发生了链支化和交联，从而使化合物的韧性增加，并调节了晶体含量和热行为。值得注意的是，特定的未公开添加剂的存在会引发 ecovio (R) 商业混合物中出现的特殊行为，而此前在类似成分的 PLA/PBAT 混合物模型中未观察到这种行为。尽管仅部分溶于氯仿，但新的ecovio (R) DCP 改性化合物在熔体中仍可使用，从而提供了一种合适、简单且经济实惠的策略，可以从市售的可堆肥化合物开始精细调节热机械性能。
Aiming at the tuning of thermo-mechanical features by chemical cross-linking, a biopolyester commercial blend based on poly(lactic acid) (PLA) with poly(butylene adipate-co-terephthalate)(PBAT) (ecovio (R) T2280, BASF) was processed in Brabender in the presence of dicumyl peroxide (DCP, 0-0.2 wt.-%). The effect of DCP addition was investigated and rationalized by means of solubility tests and gel content evaluation, as well as rheological, mechanical, and molecular weight analysis of the prepared compounds. Moreover, detailed DSC and TMDSC investigations provided a deep insight into the structural modifications occurred at the macromolecular level. We found that chain branching as well as cross-linking occurred in the samples processed in the presence of DCP, thus returning compounds having increased toughness and modulated crystalline content and thermal behavior. Noteworthy, the presence of specific, undisclosed additives, triggers the occurrence of peculiar behaviors in the ecovio (R) commercial blend, not previously observed in model PLA/PBAT blends of similar composition. Despite only partially soluble in chloroform, the new ecovio (R) DCP-modified compounds still remained workable in the melt, thus providing a suitable, simple and economically affordable strategy to finely modulate the thermo-mechanical properties starting from a commercially available, compostable compound.