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