EFFECT OF K-CARRAGEENAN ON MECHANICAL, THERMAL AND BIODEGRADABLE PROPERTIES OF STARCH–CARBOXYMETHYL CELLULOSE (CMC) BIOPLASTIC
Akbar Hanif Dawam Abdullah, Bonita Firdiana, Rossy Choerun Nissa, Rahmat Satoto, Myrtha Karina, Dina Fransiska, Nurhayati Nurhayati, Agusman Agusman, Hari Eko Irianto, P Priambudi, Sri Marliah, Ismadi Ismadi
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 melt-mixing 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 κ-carrageenan was identified as not affecting the biodegradability of the bioplastics.