University of Sfax, Faculty of Science, LMSE, BP 802-3018 Sfax, Tunisia.
LEPAMAP-PRODIS Research Group, University of Girona, C/ Maria AurèliaCapmany, 61 - 17003 Girona, Spain.
Int J Biol Macromol. 2021 Jul 31;183:267-275. doi: 10.1016/j.ijbiomac.2021.04.102. Epub 2021 Apr 19.
Poly(butylene adipate-Co-terephthalate)/thermoplasticized starch PBAT/TPS blends are among the most produced biodegradable plastic for wide application packaging, sharing more than 20% of the global production capacity of bioplastics. However, this class of material suffers from poor mechanical strength in comparison of neat PBAT, especially when the TPS content exceeds 30 wt%. Aiming at enhancing the mechanical performance of PBAT/TPS blends while maintaining relatively high TPS content, cellulose nanofibrils (CNFs) was incorporated into the TPS phase using twin screw extrusion. The effects of CNFs content on the microstructure, mechanical properties, melt-rheology and humidity absorption were investigated. An enhancement in the tensile strength and modulus was noted with the inclusion of CNFs, with optimal performance attained at 8 wt% of CNFs. A narrowing in the distribution of the TPS nodules within the PBAT matrix was also observed with the addition of CNFs, which is expected to be on the origin of the main evolution in the mechanical, rheological and humidity observed. Because of the availability of CNFs, biodegradability and facile processability, the ternary PBAT-TPS-CNFs blends might contribute to improve the performance of this class of biodegradable bioplastic.
聚己二酸/对苯二甲酸丁二酯/热塑性淀粉（PBAT/TPS）共混物是目前产量最大的可生物降解塑料之一，广泛应用于包装领域，占全球生物塑料总产量的 20%以上。然而，与纯 PBAT 相比，这类材料的机械强度较差，尤其是当 TPS 含量超过 30wt%时。为了在保持相对较高 TPS 含量的同时提高 PBAT/TPS 共混物的力学性能，采用双螺杆挤出法将纤维素纳米纤维（CNFs）引入 TPS 相中。研究了 CNFs 含量对共混物的微观结构、力学性能、熔体流变性能和吸湿性能的影响。结果表明，随着 CNFs 的加入，拉伸强度和模量得到了提高，在 CNFs 含量为 8wt%时达到最佳性能。加入 CNFs 后，TPS 颗粒在 PBAT 基体中的分布变窄，这有望成为观察到的力学、流变和湿度性能主要演变的原因。由于 CNFs 的可用性、生物降解性和易于加工性，三元 PBAT-TPS-CNFs 共混物可能有助于提高这类可生物降解生物塑料的性能。
