Supertough, Ultrastrong, and Transparent Poly(lactic acid) via Directly Hot Pressing under Cyclic Compressing-Releasing

Poly(lactic acid) (PLA) could be a promising replacement for nondegradable polymers, only if it is toughened. However, the current technique of toughening PLA generally requires additional components or post-treatment, and the conflicts among toughness, strength, and transparency are still to be overcome. Herein, by employing a novel compressing-releasing (CCR) process, we fabricated supertough, ultrastrong, and transparent PLA directly via hot pressing. Through characterizations we obtained PLA with superior tensile strength and strain at break of 84.1 MPa and 272.4%, respectively, which are 28% and 40 times higher than conventional technique-processed PLA, as well as enhanced heat resistance. The mechanism of CCR-induced gt-to-gg conformational transition was then investigated. Moreover, the correlation between tensile properties and gg conformer was also established. To sum up, we demonstrate that this work not only promotes the sustainable development of PLA with outstanding mechanical properties but also paves a new avenue toward a controlled conformational transition of polymers under mild processing conditions.

Automated summary

By utilizing a novel compressing-releasing process, supertough, ultrastrong, and transparent PLA was fabricated directly via hot pressing. The PLA obtained exhibited superior tensile strength and strain at break, as well as enhanced heat resistance, surpassing conventionally processed PLA. The mechanism of CCR-induced gt-to-gg conformational transition was investigated, demonstrating a new avenue for controlling polymer conformational transitions under mild processing conditions.