S. Z. A. Zaidi and A. Crosky
High Strength, High Toughness PolyhydroxybutyrateCoValerate Based Biocomposites
93 - 97
2017
11
1
International Journal of Materials and Metallurgical Engineering
https://publications.waset.org/pdf/10006410
https://publications.waset.org/vol/121
World Academy of Science, Engineering and Technology
Biocomposites is a field that has gained much scientific attention due to the current substantial consumption of nonrenewable resources and the environmentally harmful disposal methods required for traditional polymer composites. Research on natural fiber reinforced polyhydroxyalkanoates (PHAs) has gained considerable momentum over the past decade. There is little work on PHAs reinforced with unidirectional (UD) natural fibers and little work on using epoxidized natural rubber (ENR) as a toughening agent for PHAbased biocomposites. In this work, we prepared polyhydroxybutyratecovalerate (PHBV) biocomposites reinforced with UD 30 wt. flax fibers and evaluated the use of ENR with 50 epoxidation (ENR50) as a toughening agent for PHBV biocomposites. Quasiunidirectional flaxPHBV composites were prepared by hand layup, powder impregnation followed by compression molding. Toughening agents – polybutylene adiphatecoterephthalate (PBAT) and ENR50 – were cryogenically ground into powder and mechanically mixed with main matrix PHBV to maintain the powder impregnation process. The tensile, flexural and impact properties of the biocomposites were measured and morphology of the composites examined using optical microscopy (OM) and scanning electron microscopy (SEM). The UD biocomposites showed exceptionally high mechanical properties as compared to the results obtained previously where only short fibers have been used. The improved tensile and flexural properties were attributed to the continuous nature of the fiber reinforcement and the increased proportion of fibers in the loading direction. The improved impact properties were attributed to a larger surface area for fibermatrix debonding and for subsequent sliding and fiber pullout mechanisms to act on, allowing more energy to be absorbed. Coating cryogenically ground ENR50 particles with PHBV powder successfully inhibits the selfhealing nature of ENR50, preventing particles from coalescing and overcoming problems in mechanical mixing, compounding and molding. Cryogenic grinding, followed by powder impregnation and subsequent compression molding is an effective route to the production of highmechanicalproperty biocomposites based on renewable resources for highobsolescence applications such as plastic casings for consumer electronics.
Open Science Index 121, 2017