Fabrication and Characterization of Bio-Based Poly Lactic Acid/Polyhydroxybutyrate-Valerate (PLA/PHBV) Blend With Nanoclay

Abstract

The objective of this research is to prepare a hybrid biopolymer blend using PLA and PHBV with enhanced mechanical and thermal properties. Bio-based PLA and PHBV blends were prepared using the melt-mixing procedure. Tensile, FTIR, DSC, TGA, optical microscopy (OM), and scanning electron microscopy (SEM) tests were performed to investigate mechanical properties, bonding interaction, glass transition temperature, melting and crystalline enthalpy, thermal decomposition, and morphological analysis. Different percent (1, 2, and 3 wt%) of nanoclay was added to the system to observe the bonding interaction. It was observed that the crystallinity increases with increasing amount of nanoclay. The result showed that the tensile strength of PLA thin film and PHBV film was found to be 31.1 MPa and 14.41 MPa, respectively. Hence, PLA has better mechanical property than PHBV. On the other hand, thermal property of PHBV thin film was found to be better than that of PLA. To optimize both mechanical and thermal properties of PLA and PHBV hybrid biopolymer blend, using various combinations of PLA/PHBV including 25/75, 50/50 and 75/25 wt% a hybrid biopolymer blend was prepared. Among them, PLA-PHBV (75/25 wt%) with 2 wt% nanoclay resulted in the best outcome. The tensile strength of this prepared polymer blend was 29.34 MPa. Thermal analysis demonstrated two melting temperatures: 238.37 °C and 308.31 °C, respectively. Two glass transition temperatures were found from thermal tests which are the indication of the solution immiscibility. It had also been observed that the adding of nanoclay enhances tensile properties as well as thermal stability up to 2 wt%. It is revealed from the optical and SEM micrographs that the 2 wt% NC was dispersed uniformly throughout the resin blend.