Synthesis of Degradable Mulch Films from Bambara (Vigna Subterranean.L) Groundnut Starch/LDPE Composites

Starch is a natural carbohydrate-based polymer that is globally available from various natural sources such as Bambara groundnut, wheat, rice, corn and potato with some inherent limitations to its industrial applications such as hydrophilicity, poor mechanical properties and dimensional instability. Biodegradable composites from Starch and Low-density Polyethylene were synthetically developed. The isolated native starch was modified by annealing at 50C for 48 hr (BAS), and heatmoisture treated at 100C for 16 hr at 25 % moisture level (BHS). The crude protein of BG flour was 16.88 %. The amylose content of the flour and native starch was 6.10 % and 27.70 %, respectively. Biodegradable composites were prepared by blending the native and modified starches with LDPE at 1 %, 3 % and 5 % ww-1. Hydrothermal modification increased the gelatinization profile of the starch but reduces its pasting properties. Swelling and solubility of the flour and starches increased with increase in temperature. The tensile strength (T. S), enlongation at break percentage (EB %), water absorption test and 6 months soil burial test was carried out to determine the degradability. The tensile strength of the composite was lower than 6.37MPa for the 100 % LDPE. BAC5 showed the highest level of degradability among other composites at the rate of 35.27 %. Annealed starch and Heat moisture treated starch contributes better to starch degradability than the native starch.