A Scalable Biobased Leatherlike Material via the Covalent Integration of Kombucha-Derived Bacterial Cellulose and Polyurethane

Leatherlike materials derived from biobased composites, such as cellulose, play a vital role in niche applications, particularly when biodegradability and sustainability are considered. The production of leatherlike materials typically employs noncovalent modifications, while covalent modifications remain underexplored. In this study, we present a method for preparing leatherlike materials by covalently modifying BC with polyurethane prepolymers, resulting in porous polymeric layers that encase KBC layers upon curing. The deconvoluted carbonyl IR region and XPS spectra confirm the formation of covalent linkages between the KBC and polyurethane. We found that incorporating a porous polyurethane layer enhances the physical properties by 2-fold and facilitates water vapor permeability to about 150 and 120 mg/cm2·day for PEG- and PCL-based bacterial cellulose–polyurethane leatherlike materials BCPU1 and BCPU2, respectively, demonstrating ∼9% rebound resilience, which is responsible for the shock-absorbing characteristics. Upon conducting magnetic resonance imaging (MRI) studies on the leatherlike material, we observed a homogeneous distribution of pores within the polymer layer. Notably, this material has been successfully implemented as a footwear component, demonstrating its practical scalability. This biobased leatherlike composite presents a promising avenue for sustainable, biodegradable alternatives to natural leather.