My focus is in the realm of biodegradable and biorenewable polymers. The primary goal is to further the understanding of the processing and applications of poly-(hydroxyalkanoates) (PHA).
PHB and natural fiber composite have the potential to be cost effective wood substitutes in structural design elements. In order to meet this end-use application goal, the interaction between the fibers and plastic must be strengthened. I am using mechanical and spectroscopic techniques to understand the interactions between these two phases to determine the relevant design parameters from a molecular viewpoint.
Structural insulated panels (SIPs) are a potential target application for biocomposites made from PHAs. A lightweight, foamed material is sandwiched between two load-bearing composites in a SIP. We are attempting to make foam from semi-crystalline PHA that will provide high thermal resistivity. To accomplish this goal, the foam must have many small, closed cell bubbles trapped in the matrix. PHAs do not make good foams because the extensional viscosity is too low to support growing bubbles and thus many of the nucleated gas pockets coalesce or collapse. Adding nanoparticles to the matrix can help nucleate more bubbles due to the high surface area and prevent collapse by aggregating at the bubble surface, providing a barrier to gas diffusion and stiffening the PHA. We are trying such an approach with silica nanoparticles of varying surface chemistry to understand the role of nanoparticles in nucleation and stabilization.