Waterborne polyurethane synthesized for leather with excellent wear and hydrolysis resistance enabled by bio-based poly(trimethylene carbonate) and l-lysine diisocyanate

A wide application of bio-based waterborne polyurethanes (BWPU) in the synthetic leather is the main direction in the future, however, it has been a great challenge for its development because of the poor mechanical properties and water resistance of BWPU. To address this issue, bio-based poly(trimethylene carbonate) diols (PTMC-OH) with a theoretical molecular weight of 2000 g/mol was prepared via ring-opening polymerization of trimethylene carbonate and 1,4-butanediol as an initiator. PTMC-OH, bio-based l-lysine diisocyanate as building blocks, and trimethylolpropane as a crosslinking agent were employed to prepare a series of linear and crosslinked bio-based waterborne polyurethanes (LBWPU and CBWPU). Remarkably, CBWPU-1 % film with crosslinked structure had high tensile strength and toughness shown as 41.5 MPa and 131 MJ·m−3, respectively, while it also showed excellent hydrolysis resistance with the ignorable degradation in aqueous solution after 35 days since the weight loss of about 1.4 wt%. In addition, the synthetic leather coating made from CBWPU-1 % exhibited exceptional wear resistance, enduring 50,000 rubs without damages on the CBWPU coating. This work presents a facile and efficient method for the synthesis of BWPU and applying them to manufacture the bio-based synthetic leather.