(409a) Characterization and Use of Pollen As a Biorenewable Filler for Polymer Composites

Pollen grains have the potential to be effective biorenewable fillers in polymer matrices in part due to their high mechanical strength, chemical stability, and unique architectures. In addition, pollen-polymer composites are attractive because they could form the basis for a new class of light-weight, high strength materials with a sustainable plant-based filler. Using pollen as a filler also provides a unique way to study how filler microstructure affects wetting and adhesion between the phases. In this work, routes for optimizing the wetting and adhesion of pollen fillers in a polymer matrix are further explored. The effect of chemically modified pollen as a reinforcing filler in poly(vinyl acetate) (PVAc), a common commercial polymer, is investigated. PVAc was chosen because of its ester groups, which may interact with ester groups on pollen. Pollen grains are chemically modified with the silane coupling agent vinyltrimethoxysilane (VTMS), in order to graft polymer chains on pollen grains through in situ free radical polymerization. The effectiveness of modified pollen fillers is characterized by mechanical properties, glass transition temperature, and interfacial morphology of pollen-polymer composites as a function of pollen loading. Scanning electron micrographs show a thick coating of grafted polymer on modified pollen, indicating enhanced interfacial morphology versus unmodified pollen. Solid-liquid interactions of pollen with various probe molecules are also measured with inverse high pressure liquid chromatography (IHPLC). The retention and heat of interaction of various chemical probes have been measured. This information may be useful in predicting the compatibility of pollen with different polymers. Preliminary results suggest that polymers with alcohol or amide groups may be more compatible with pollen than polymers previously studied.