Investigation of the TPS Effect on the Biodegradability of Agricultural Mulches Based on PLA and LDPE

Research subject:

 The need to increase agricultural production in proportion to population growth and water crisis management requires initiatives that can increase the quantity and quality of crops by using soil moisture storage methods while preserving the environment. In this study, the effect of different wt. % of Thermoplastic starch (TPS) with maleic anhydride (MA) as compatibilizer and nanoclay (15A) on gel content and mechanical properties of Polylactic acid (PLA) and blends of  Linear low-density polyethylene/ Low-density polyethylene (LLDPE / LDPE) was evaluated.

Research approach: 

Here, 0, 10, 20 and 30 wt. % TPS were added to the blends of LLDPE/LDPE (20/80) and also PLA. Independent parameters in the experimental design were wt. % of TPS, basic polymer type that was PLA or TPS and aging test. For dependent parameters were considered gel content, tensile strength, elongation at break and elastic modulus. Experiments were designed in General Full Factorial Design and performed in three replications.

Gel content in LLDPE/LDPE blends increased with the addition of TPS and decreased for PLA blends. The gel content change range for experimental samples before and after the aging test was between 10 to 21 and 2 to 5 percent, respectively. Tensile strength and elongation at break were reduced by adding TPS in both series of compounds before aging test. But this reducing rate was less in the 20 wt. % of TPS. The values ​​of tensile strength and elongation at break were: 12 to 19 MPa and 50 to 350 percent, respectively. These values changed after the aging test between 7 and 11 MPa and from zero to 5 percent, respectively.
Keywords: biodegradability, low density polyethylene, poly lactic acid, thermoplastic starch.