The Effects of Natural Weathering on the Properties of Linear Density Polyethylene (LDPE)/Thermoplastic Sago Starch (TPSS) Blends

Linear density polyethylene (LDPE)/thermoplastic sago starch (TPSS) blends with and without the addition of compatibilizer (Polyethylene-grafted-Maleic Anhydride, PE-g-MA), with different TPSS loadings (10, 20, 30, 40 and 50wt.%) were prepared. These blends were subjected to a natural weathering condition which was tropical climate in Penang, Malaysia, for 3 and 6 months. Results of mechanical tests showed that with an increase of weathering time, the tensile strength and elongation at break decreased for both uncompatibilized and compatibilized blends. But the Young modulus increased during 3 months and 6 months of exposure. With the increase of TPSS loading, tensile strength and elongation at break were also decreased. The Young modulus however increased with the increase in TPSS loading. Scanning electron microscopy (SEM) on blends surfaces after weathering showed that the degradability increased with the increase of TPSS loading as well as exposure time. This explained the reduction in tensile strength and elongation at break after weathering. Fourier transform infrared spectroscopy results on the blends after exposure to natural weathering indicated the presence of carbonyl, vinyl, and hydroxyl groups, which formed from various chemical reactions taking place during weathering.