Biomimetic Bridging for Reconstructing Biomass Components toward Significantly Enhanced Films from the Full Composition of Bamboo

Bamboo is a kind of renewable natural polymer resource. Using bamboo biomass without a component isolation process can be a sustainable route for the preparation of an eco-friendly biomass film. Inspired by the natural structure of plant biomass, we designed to introduce a bionic interaction, being akin to the role of hemicellulose in natural biomass, for connecting the cellulose and lignin components using tannic acid-modified cellulose nanocrystals (TA@CNCs) as the bridging molecules. In order to make up for the size difference between the cellulosic molecules and lignin particles, cellulose nanocrystals (CNCs) served as the carriers of TA. Core–shell hybrids of TA@CNCs were prepared and added into the solution of bamboo powder dissolved in a tetrabutylammonium hydroxide/dimethyl sulfoxide aqueous solvent (TBAH/H2O/DMSO) followed by gelation in air and regeneration in water to prepare the bamboo-derived biomass films with high strength. The results showed that the tensile strength of the as-prepared films was effectively improved from 55.4 to 127.2 MPa by adding 5 wt % TA@CNCs. Structural analyses indicated that TA@CNCs serve as an excellent modifier for the enhancement of cellulose–lignin interfaces by rationally reconstructing the biomimetic hydrogen-bonded system.