Development of poly(lactic acid) ternary blends properties for plastic packaging applications by thermoforming technique

Abstract

This research was aimed to study the poly(lactic acid) (PLA) blends between poly(butylene succinate) (PBS) and ethylene-propylene-diene rubber (EPDM) for thermoforming. The objectives of this type of ternary blends were to study some properties such as morphology, mechanical properties and thermal properties. which is divided into two component blends and three components. This research was divided into 2 parts. The first part studied PLA and PBS blends ratio at PLA/PBS (90/10), PLA/PBS (80/20) and PLA/PBS (70/30). After that finding the suitable ratio, the second part studied PLA/PBS (80/20) and EPDM ternary blends at ratio PLA/PBS/EPDM (80/15/5), PLA/PBS/EPDM (80/10/10) and PLA/PBS/EPDM (80/5/15). The sample can be molded by thermoforming. The polymer blends were prepared via internal mixer and sample films was prepared by compression molding. The results found that the morphological analysis observed the phase separation of PLA/PBS, PLA/EPDM and PLA/PBS/EPDM ternary blends and showed the minor phase dispersed in PLA matrix phase. The domain size of EPDM phase in PLA/PBS/EPDM ternary blends increased with the increase of EPDM contents. The results of tensile properties showed that Young’s modulus of PLA/PBS (80/20) blends was higher than that of PLA/EPDM (80/20) and PLA/PBS/EPDM ternary blends. While the strain at break of PLA/EPDM (80/20) blends was higher than that of PLA/PBS (80/20) blends and the strain at break of ternary blends increased with increasing EPDM content, this indicated the presence of EPDM enhanced the strain at break of PLA. Additionally, the ternary blends of PLA/PBS/EPDM (80/5/15) exhibited higher impact strength than pure PLA.

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