All cellulose composites prepared by hydroxyethyl cellulose and cellulose nanocrystals through the crosslink of polyisocyanate

In this work, all cellulose composite (ACC) films were prepared through a blocked polyisocyanate (BPIC) induced cross-linking of hydroxyethyl cellulose (HEC) and cellulose nanocrystals (CNC). The chemical characterization indicates that the covalent bonds have been formed between HEC and CNC. Mechanical test shows that the addition of 4 % CNC into the HEC matrix improves the tensile strength by 120.2 % compared to the neat HEC film. The further incorporation of 10 % BPIC into the above ACC film can enhance the tensile strength by 280.2 %. The water contact angles of the ACC film that constituted by 4 % CNC and 10 % BPIC is increased to 100.1 degrees while the thermal decomposition temperature is up to 210 degrees C. The morphological analysis suggests that the CNC is beneficial to the dispersion of the cross-linked HEC, which increases the elongation at break and maintains the excellent tensile strength meanwhile.