EFFECT OF κ-CARRAGEENAN ON MECHANICAL, THERMAL AND BIODEGRADABLE PROPERTIES OF STARCH–CARBOXYMETHYL CELLULOSE (CMC) BIOPLASTIC

Abstract

Starch–carboxymethyl cellulose (CMC) bioplastics have limited mechanical properties. Carrageenan from seaweed is a potential reinforcement material for improving the mechanical properties of bioplastics. This study aimed to determine the effect of Kappa (κ)-carrageenan on the mechanical and thermal properties and biodegradability of starch–CMC bioplastics. In this study, carrageenan at concentrations of 0%, 10%, 15%, 20%, 25% and 30% was used. The meltmixing process was conducted at 130 °C for 4 min, using a mixer and then hot-pressing (30 kgf/cm2) at 150 °C for 5 min. The results indicated that the higher κ-carrageenan concentration increased the strength of bioplastics up to 15.7 MPa. The fracture analysis via scanning electron microscopy–energy-dispersive X-ray spectroscopy indicated the distribution of sulfur (S) elements that described the dispersion of κ-carrageenan. The Fourier transform infrared spectroscopy spectra revealed that the interaction between the starch–CMC matrix and κ-carrageenan formed a tight hydrogen bond network. The lowest mass reduction observed by thermogravimetric analysis occurred in bioplastics with 25% carrageenan, decreasing by 48% compared with bioplastics without κ-carrageenan. The addition of κcarrageenan was identified as not affecting the biodegradability of the bioplastics.