Evaluation of Mechanical and Thermal Properties of MCC/PLA Composite Compatibilized with Modified Cellulose

Abstract

Biocomposite films from polylactic acid (PLA) and 40wt% banana stem microcrystalline cellulose (BS MCC) were prepared by a twin screw extruder. Two types of cellulose ester, i.e. cellulose butyrate and cellulose laurate were used as a compatibilizer. The cellulose esters were prepared via acylation process under microwave heating. The proper condition for preparing cellulose butyrate was 180 sec of reaction time and 80 watt of power output, while the suitable condition for preparing cellulose laurate was 150 sec of reaction time and 160 watt of power output, respectively. These suitable conditions led to the highest %WI and the absence of the degradation of cellulose. The FT-IR and NMR spectra techniques confirmed that butyrate and laurate were grafted on the BS MCC. For biocomposite films, although the increase of cellulose laurate or cellulose butyrate induced the decrease of Youngs modulus of 40wt% BS MCC/PLA composite, the elongation at break of 40wt% BS MCC/PLA composite was increased. Besides, the addition of 5wt% cellulose butyrate or cellulose laurate resulted in the highest tensile properties, especially in elongation at break, when compared to other contents of cellulose ester. Moreover, cellulose butyrate is an effective compatibilizer to improve the elongation at break of 40wt% BS MCC/PLA since cellulose butyrate had better compatibility with BS MCC and PLA matrix. However, the addition of two types of cellulose ester led to the decrease in the degradation temperature (Td) of 40wt% BS MCC/PLA, particularly in case of the addition of cellulose laurate.