Samaniego-Aguilar Kerly, Sánchez-Safont Estefanía, Arrillaga Alex, Anakabe Jon, Gamez-Perez Jose, Cabedo Luis
Polymers and Advanced Materials Group (PIMA), Universitat Jaume I, Av. Sos Baynat s/n, 12071 Castelló, Spain.
Leartiker S. Coop., Xemein Etorbidea 12, 48270 Markina-Xemein, Spain.
Polymers (Basel). 2022 Jun 9;14(12):2337. doi: 10.3390/polym14122337.
Moving toward a more sustainable production model based on a circular economy, biopolymers are considered as one of the most promising alternatives to reduce the dependence on oil-based plastics. Polyhydroxybutyrate-co-valerate (PHBV), a bacterial biopolyester from the polyhydroxialkanoates (PHAs) family, seems to be an attractive candidate to replace commodities in many applications such as rigid packaging, among others, due to its excellent overall physicochemical and mechanical properties. However, it presents a relatively poor thermal stability, low toughness and ductility, thus limiting its applicability with respect to other polymers such as polypropylene (PP). To improve the performance of PHBV, reactive blending with an elastomer seems to be a proper cost-effective strategy that would lead to increased ductility and toughness by rubber toughening mechanisms. Hence, the objective of this work was the development and characterization of toughness-improved blends of PHBV with thermoplastic polyurethane (TPU) using hexamethylene diisocyanate (HMDI) as a reactive extrusion agent. To better understand the role of the elastomer and the compatibilizer, the morphological, rheological, thermal, and mechanical behavior of the blends were investigated. To explore the in-service performance of the blends, mechanical and long-term creep characterization were conducted at three different temperatures (-20, 23, 50 °C). Furthermore, the biodegradability in composting conditions has also been tested. The results showed that HMDI proved its efficiency as a compatibilizer in this system, reducing the average particle size of the TPU disperse phase and enhancing the adhesion between the PHBV matrix and TPU elastomer. Although the sole incorporation of the TPU leads to slight improvements in toughness, the compatibilizer plays a key role in improving the overall performance of the blends, leading to a clear improvement in toughness and long-term behavior.
朝着基于循环经济的更可持续生产模式发展，生物聚合物被认为是减少对石油基塑料依赖的最有前途的替代品之一。聚羟基丁酸酯-共-戊酸酯（PHBV）是聚羟基链烷酸酯（PHA）家族中的一种细菌生物聚酯，由于其优异的整体物理化学和机械性能，似乎是在许多应用（如刚性包装等）中替代商品的有吸引力的候选材料。然而，它的热稳定性相对较差，韧性和延展性较低，因此在与其他聚合物（如聚丙烯（PP））相比时限制了其适用性。为了提高PHBV的性能，与弹性体进行反应共混似乎是一种合适的具有成本效益的策略，通过橡胶增韧机制可以提高延展性和韧性。因此，这项工作的目的是使用六亚甲基二异氰酸酯（HMDI）作为反应挤出剂，开发和表征PHBV与热塑性聚氨酯（TPU）的韧性改进共混物。为了更好地理解弹性体和增容剂的作用，研究了共混物的形态、流变、热和机械行为。为了探索共混物的使用性能，在三个不同温度（-20、23、50°C）下进行了机械和长期蠕变表征。此外，还测试了在堆肥条件下的生物降解性。结果表明，HMDI在该体系中证明了其作为增容剂的有效性，减小了TPU分散相的平均粒径，增强了PHBV基体与TPU弹性体之间的粘附力。虽然单独加入TPU会使韧性略有提高，但增容剂在改善共混物的整体性能方面起着关键作用，使韧性和长期性能有明显改善。
