A facile strategy for preparing lignocellulose-based bioplastic by grafting with quaternary ammonium salts

Abstract

The development of lignocellulose-based bioplastic is still a challenge mainly due to their high crystallinity and extensive hydrogen bond network. Sustainable modification strategies are thus essential and vital currently. Here, we proposed a thermoplasticization process by combining carboxylation and subsequent grafting with quaternary ammonium based on electrostatic interaction. Continuous steam exploded sisal fibers (SFs) was firstly carboxylated with periodate and sodium chlorite, and then grafted with cetyl trimethyl ammonium bromide (CTAB). A higher yield (∼90 %) of carboxylated SFs (CSFs) at a lower dosage of periodate was achieved, which implied the cost-effective of this strategy. The CSFs grafted with CTAB (CCSFs) showed an obvious secondary relaxation between 50 – 90 °C, and could be hot-pressed into transparent sheets. The tensile strength of hot-pressed sheet reached a maximum of 27.8 MPa at the weight ratios of 0.2 (periodate/SFs) and 1.0 (CTAB/CSFs). The interface bonding between CCSFs was investigated by scanning electron microscope and atomic force microscope, which revealed the effect mechanism of the dosage of periodate and CTAB on mechanical properties of hot-pressed sheets. This strategy represents a potential green and sustainable route to produce lignocellulose-based bioplastic in industry.