AGAR FROM MALAYSIAN RED SEAWEED AS POTENTIAL MATERIAL FOR SYNTHESIS OF BIOPLASTIC FILM

Abstract

The main aim of this study was to identify the potential use of agar extracted from red seaweed, Gracilaria salicornia, collected from the coastal area of Malaysia as the raw material for synthesis of bioplastic film. Agar was extracted via two extraction methods: (1) alkali extraction method and (2) photo bleaching extraction method. The yields of agar by both of the methods were 9 to 11 %. The alkali extracted agar (AEA) and photo bleached agar (PBA) were incorporated as the raw materials for the formation of bioplastic films while sago starch and glycerol were added to increase workability. Physicochemical properties of the two bioplastic films were characterised. FTIR analysis confirmed the presence of agar in both plastic films with the presence of 3,6- anhydrogalactose residues and further indicated that the interactions of agar and sago starch were strong in both PBA and AEA films. The results showed that tensile strength and percent elongation of PBA film (3.067 MPa, 3.270 %) was higher than AEA film (2.431 MPa, 2.476 %). Thermogravimetric analysis (TGA; % residual weight) revealed that AEA film has higher thermal stability (14.80 %) than PBA film (10.27 %) while rheological results proved that both films exhibited non-Newtonian behaviors. The AEA film was completely decomposed after 30 days in the soil burial test. Results of current study show a wide range of future possibilities and commercial applications of AEA and PBA bioplastic films.

Keywords

• Agar
• Gracilaria salicornia
• Alkali extraction method
• Photo bleaching extraction method
• Bioplastic film