Effect of agar on physical properties of thermoplastic starch derived from sugar palm tree

Modification of thermoplastic starch with other natural polymer is a promising research since the combination of both material will produce a fully green polymer with modified properties. The aim of this paper is to investigate the effects of agar on physical properties of thermoplastic sugar palm starch (SPS). Various types of thermoplasctic SPS based polymer were prepared by blending SPS and agar with the presence of glycerol as a plasticiser. Agar with various contents (10, 20, 30, and 40 wt%) were mixed with thermoplastic SPS via melt mixing before compression moulded into 3 mm mould plate. The prepared laminates were characterised for the moisture content, density, water absorption, thickness swelling and water solubility. Results showed that incorporation of agar has slightly increased the moisture content and water absorption capacity of the blends. Slight increment in thickness swelling was observed for thermoplastic SPS after incorporation with agar (40 wt%). Water solubility of thermoplastic SPS was slightly increased with incorporation of agar (40 wt%). Similar density was recorded for all ratios of agar, which indicated that the incorporation of agar did not influence the density of thermoplastic SPS. In conclusion, the incorporation of agar has slightly increased the hydrophilic behaviour of thermoplastic SPS.