Production of flame-resistant bacterial cellulose using whey protein isolate or casein via physical entrapment and crosslinking

Abstract

This study aims to produce flame-resistant bacterial celluloses (BCs) by applying milk-derived proteins (whey protein isolate (WPI) and casein), and improve the bonding strengths between the milk-derived proteins and BC fibers via physical entrapment and crosslinking. The production conditions, namely the protein amount, production method, citric acid concentration, and crosslinker:catalyst molar ratio, were optimized by determining the residual masses of the flame-resistant BC samples at 1000 °C using thermogravimetric analysis. The samples fabricated via combined physical entrapment and crosslinking using a WPI or casein amount of 50 wt% relative to BC and citric acid concentration of 10% (w/v) presented the highest residual mass at 1000 °C. The chemical and physical structures of the BCs fabricated using WPI, or casein, were examined. Surface characterization confirmed that WPI and casein were successfully entrapped and crosslinked within the BC matrix, and the BC nanostructure did not change considerably. Furthermore, the bonding strengths between the milk-derived proteins and BC fibers were evaluated using the flame resistance to washing experiment. The as-produced BCs maintained their flame resistance after three consecutive washing steps. The durability of the flame-resistant BCs was evaluated using the mechanical properties, fabric softness, crease recovery, water resistance, and dimensional stability of the samples. The durability of flame-resistant BCs produced using WPI or casein via combined entrapment and crosslinking was comparable to that of cowhide leather samples of similar thickness with BC. This study provides an efficient method for fabricating flame-resistant BC using WPI or casein via entrapment and crosslinking. © 2023, The Author(s), under exclusive licence to Springer Nature B.V.