Effect of Potassium Sorbate on the Mechanical and Thermal Behaviors of Multi-blends Based on LLDPE/LDPE/PLA with PE-g-MA as Compatiblizer

In the present study, the role of potassium sorbate on the mechanical and thermal properties of LLDPE/LDPE/PLA/PE-g-MA modified blends was evaluated. A series of blends of LLDPE/LDPE/PLA with the ratio of (80/20%) LLDPE/LDPE and 10, 20, and 30% PLA was prepared using co-rotating twin screw extrusion followed by extrusion blown film. In the first step, the mechanical properties of the samples were determined and the compositions of 20% PLA were optimized. In the second step, the properties were evaluated again by loading 4 phr potassium sorbate. The tensile strength of the of LLDPE/LDPE/PLA/PE-g-MA film enhanced from 7.93 Mpa to 11.71 Mpa and elongation at break from 282.57% to 551.57%, respectively. Thermal behavior of multi-blends of LLDPE/LDPE/PLA with and without potassium sorbate were studied using Differential Scanning Calorimetry (DSC). The results indicated that the presence of potassium sorbate caused the T_m and Tc of the film decrease from 122.3 ℃ to 111.1 ℃ and 110.32 ℃ to 98.32 ℃, respectively, while the crystallinity increased from 46.7% to 54.3% because potassium sorbate acts as nucleating agent in the blends.