Preparation of formyl cellulose and its enhancement effect on the mechanical and barrier properties of polylactic acid films

Cellulose was modified by formic acid to prepare formyl cellulose (FC). The amount of formyl groups in FC was adjusted by controlling the reaction time, reaction temperature, and formic acid concentration. Then, FC was used to reinforce polylactic acid (PLA) films prepared by solution casting. Scanning electron microscopy (SEM) shows that long rod-like cellulose partides were broken into short rods after formylation and the introduction of FC made PLA surface rougher. The mechanical properties of PLA/FC films were improved by the inclusion of FC. Compared to pure PIA film, the PLA/FC composite film with 1 wt% FC (containing 15.79% formyl groups) showed a 48.59% increase in tensile strength and a 346% increase in Young's modulus. The addition of FC also resulted in better water barrier properties. The moisture absorption capacity and water vapor permeability were 40.56% and 51.43% lower than those of the pure-PIA film. The enhancement in properties for PLA/FC composites could be ascribed to the improved compatibility between PIA and cellulose with the introduction of hydrophobic formate groups. The PLA/FC composite films developed in this work could be highly potential for food packaging. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Formyl cellulose (FC) was prepared by modifying cellulose with formic acid, and used to reinforce polylactic acid (PLA) films. The inclusion of FC improved the mechanical properties and water barrier properties of PLA/FC films.