Development of poly(lactic acid)/poly(butylene succinate)/epoxidized natural rubber ternary blends properties with dicumyl peroxide for bioplastic packaging by thermoforming technique

Abstract

This main work aims to study the effect of dicumyl peroxide (DCP) contents on the morphological, mechanical, and thermal properties of poly(lactic acid) (PLA)/poly(butylene succinate) (PBS)/epoxidized natural rubber (ENR) ternary blends. The contents of DCP were 0.2, 0.3, 0.5, 1 and 2 parts per hundred of resin (phr). The DCP loading of 0.3 and 0.5 phr increased the percent strain at break of PLA/PBS/ENR 80/15/5 and 80/10/10. The highest percent strain at break was observed in PLA/PBS/ENR 80/10/10 with DCP 0.3 phr at about 42%, which is possibly due to the improved dispersion of DCP. The tensile strength and Young’s modulus of PLA/PBS/ENR with DCP increased when compared to those of the blends without DCP. The morphology properties, SEM micrograph showed the effective miscibility changed to the mechanical properties with addition of DCP and good dispersion state of all materials results in interfacial compatibility and enhanced the percent strain at break, compared with PLA. For FTIR showed the same peaks of polymer blends compared to pure PLA after adding all components. In addition, thermal properties, the melting temperature of all of the PLA blends was approximately 150℃. For the decomposition temperature at 10% weight loss of PLA was about 330℃ which the PLA/PBS/ENR blends with various DCP were shifted lower the decomposition temperatures than PLA. Nevertheless, in comparison with the decomposition temperature of PLA/PBS/ENR blends with the various DCP, especially at PLA/PBS/ENR (80/15/5) blends with DCP 0.3 and 0.5 phr had more thermal stability than PLA and other blends. The XRD patterns of PLA/PBS/ENR with various DCP were investigated to obtain further insight into the material’s crystallinity. A wide diffraction peak at 2θ=16° was observed for PLA. The PLA/PBS/ENR blends were observed at 2θ=19.5°and 22.5°, indicating that the PBS crystalline structure remained in the blends. However, the diffraction peak of PBS in blends did not appear as over ENR loading. For UV-vis spectrophotometer, A huge absorption band of wavelength below 225 nm belonging to PLA absorption was observed and its intensity of blends increased when PBS and ENR were added. The absorption spectra showed a strong absorption band in the visible region (400-800 nm) due to discoloration of the blends as a result of ENR loading.

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