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 ecofriendly 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.