Gholami Reza, Lawan Ibrahim, Ebrahimi Sahar, Pattulee Achiraya, Ahn Cheol-Hee, Rimdusit Sarawut
Center of Excellence in Polymeric Materials for Medical Practice Devices, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand.
Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea.
Polymers (Basel). 2024 Aug 8;16(16):2254. doi: 10.3390/polym16162254.
This study investigated the sustainable toughening of polylactic acid (PLA) by incorporating ultrafine fully vulcanized powdered natural rubber graft-copolymerized with poly-styrene-co-acrylonitrile (UFPNR-SAN). We investigated the effect of the styrene-to-acrylonitrile ratio (ST:AN) used during the grafting process on the final UFPNR-SAN compatibility with PLA. The ST:AN ratio was systematically varied during the grafting reaction to prepare UFPNR-SAN with a range of different surface energies. The ST:AN ratio of 4:1 showed the highest compatibility with the PLA matrix, attributed to optimal interfacial interactions and improved dispersion, as indicated by contact angle measurements and SEM observations. This resulted in a remarkable toughening of the PLA/UFPNR-SAN composite. For instance, an obvious fully ductile behavior without crack formation and flexural strain of around 17.5% against 5% of the neat PLA was recorded. In addition, 3.5 times improvement in the impact strength of the composite at 25 wt% dosage of the UFPNR-SAN was also achieved without compromising thermal properties. Overall, this study established the suitable ST:AN ratio on the grafting onto natural rubber to enhance interfacial interactions with PLA and its effects on the properties of the resulting PLA/UFPNR-SAN bio-based composite.
本研究通过加入与苯乙烯 - 丙烯腈接枝共聚的超细完全硫化粉末天然橡胶（UFPNR - SAN）来研究聚乳酸（PLA）的可持续增韧。我们研究了接枝过程中使用的苯乙烯与丙烯腈比例（ST:AN）对最终UFPNR - SAN与PLA相容性的影响。在接枝反应过程中系统地改变ST:AN比例，以制备具有一系列不同表面能的UFPNR - SAN。4:1的ST:AN比例与PLA基体显示出最高的相容性，这归因于最佳的界面相互作用和改善的分散性，接触角测量和扫描电子显微镜观察表明了这一点。这导致了PLA/UFPNR - SAN复合材料的显著增韧。例如，记录到明显的完全延性行为，没有裂纹形成，弯曲应变约为17.5%，而纯PLA的弯曲应变仅为5%。此外，在UFPNR - SAN用量为25 wt%时，复合材料的冲击强度提高了3.5倍，同时不影响热性能。总体而言，本研究确定了接枝到天然橡胶上的合适ST:AN比例，以增强与PLA的界面相互作用及其对所得PLA/UFPNR - SAN生物基复合材料性能的影响。
