Effect of bacterial cellulose on properties of poly(lactic acid)

Abstract

The aim of this research is to study the mechanical and thermal properties of composites based on poly(lactic acid) (PLA) by using bacterial cellulose (BC) as a reinforcement. BC is produced by Acetobacterxylinum. To improve the interfacial adhesion between the BC and PLA matrix, BC is treated with different types of silane coupling agents (BC: Silane = 1: 0.00943) namely 3-aminopropyltrimethoxysilane (APS), N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (DMS) and N1-(3-trimethoxysilyl propyl) diethylenetriamine (TMS). PLA is also modified with maleic anhydride (MA) in order to improve the electrophilicity property of PLA. In this work, reactive composites of BC reinforced PLA are prepared using a melt compounding process with twin screw extruder and injection molding machine. The effect of various silane coupling agents of 3 types and various contents of BC (1, 3, 5wt%) on mechanical and thermal properties are studied by using universal testing machine, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The DSC analysis is shown that the addition of BC particles significantly affect the crystallization rate of PLA because BC particles can act as a nucleating agent. The addition of 5 wt% BC to PLA provides more crystalline region than BC addition of 3 wt% and 1 wt% to PLA. Moreover, PLA composite with BC modified by TMS has the highest crystalline volume, followed by the DMS and APS, respectively. Young’s modulus of PLA/5 wt% BC-TMS composite has the greatest increase compared with neat PLA. Moreover, PLA composites with BC treated by DMS have higher modulus than the one that is treated with APS.