Improving Thermal Reprocessability of Commercial Flexible Polyurethane Foam by Vitrimer Modification of the Hard Segments AITranslate

Basic Information:

DOI：https://doi.org/10.1021/acsapm.2c00595

Chinese Library Classification Number:

Citation Information:

Polyurethane foam (PUF) is widely applied in many applications that require light weight, flexibility, and high cushion capacity, but PUF industrial offcuts and end-of-life discards are a severe environmental burden. In this academic–industrial collaboration work, the dynamic covalent mechanism was adopted to modify a flexible polyether-based PUF formulated on a typical PUF recipe in industrial practice. In specific, 2-hydroxyethyl disulfide (HEDS), a disulfide diol, was used as a co-chain extender and incorporated into the hard segments of the cross-linked network by its reaction with methylene diphenyl diisocyanate (MDI). Introduction of disulfide bonds and increase in carbamate content (by the diol-isocyanate reaction) in the hard domain of the network worked together to impart improved thermal reprocessability to PUF, while the relative longer chain of HEDS reduced the second glass transition temperature (Tg2) to further facilitate thermal reprocessing. HEDS-modified PUFs showed promising thermal reprocessability at a relatively mild temperature (150 °C) and relatively short time (30–60 min), and the recycled PU sheet (PUS) products exhibited decent morphological uniformity and mechanical properties. On the other hand, the MDI-HEDS contributed to the hard segments and tailored the specific mechanical properties of the PUF. This finding can be a low-cost and feasible case for developing industrial products toward sustainability.