Scalable Fabrication of Self-Reinforced Bioplastic Composites Using Short Fiber Reinforcements

Abstract

Bioplastics and biocomposites are eco-friendly alternatives to their petrochemical derived commodity material, but tend to have inferior mechanical and thermal properties. In this work, short-fiber self-reinforced bioplastic composites (SRBCs) have been developed that seek to overcome some of these shortcomings. The SRBCs leverage melt-spun drawn poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fibers with axially-oriented crystalline structures that exhibit a ≈6.7 °C higher melt temperature than the same PHBV in isotropic form. This enables a controlled-temperature compounding process that preserves the crystalline structure of the fibers without distortion and ensures uniform distribution within the matrix. The resultant composites display a ≈35% increase in ultimate tensile strength and a ≈55% increase in impact resistance compared to neat PHBV polymer. This monolithic-type composite system, characterized by high interfacial compatibility and strong fiber-matrix adhesion, also supports high-value recycling while preserving its mechanical properties across multiple lifecycle uses. By focusing upon discontinuous short fiber reinforcement, this work provides unprecedented opportunities for scaling SRBCs through commodity application pathways such as injection molding, compression molding, and 3D printing.