High-performance, Bio-based, Degradable polyurethane thermoset and its Application in Readily Recyclable Carbon Fiber Composites

Binbo Wang, Songqi Ma*, Xiwei Xu, Qiong Li, Tao Yu, Sheng Wang, Shifeng Yan*, Yanlin Liu*, Jin Zhu

ABSTRACT: Carbon fiber (CF) reinforced polyurethane (PU) composites have attracted increasing attention in recent years. It is still a challenge to recycle the CF reinforced composites, and there is no report on recycling of CF from PU matrix. In this paper, for the first time, a readily recyclable CF reinforced PU composite was prepared based on a bio-based acetal diol: 2-(4-hydroxy-3-methoxyphenyl)-1,3-dioxan-5-ol (HMDO). The acetal diol was synthesized from lignin derivative vanillin and used to react with hexamethylene diisocyanate trimer to prepare the PU thermoset (PU-HMDO). On account of the cleavable acetal groups, the PU-HMDO could be decomposed within 40 min in low-concentration acidic solution completely. In addition, the heterocyclic structures of acetal and isocyanurate resulted in excellent mechanical and thermal properties of PU-HMDO, the tensile strength was 68 MPa, elongation at break was 7.9%, glass transition temperature (Tg) was 130 °C, which are comparable to PU thermoset (PU-BPA) from commercially available diol bisphenol A (BPA). The thermal stability of PU-HMDO was even higher than PU-BPA. The PU-HMDO based CF composite exhibited similar mechanical properties to the PU-BPA based CF composite, and CF could be reclaimed with maintained microscale morphology, chemical structures and mechanical properties under mild acid conditions. This work will open a door to develop readily recyclable PU-based CF composite.

论文链接：https://pubs.acs.org/doi/10.1021/acssuschemeng.0c02330