Oluwatimilehin â??Timiâ?? Fadiran
Advisor: Dr. J. Carson Meredith

Pollen as a Renewable Reinforcing Filler for Thermosetting Polymer

Abstract
Pollen has the potential to be an effective filler in polymers in part due to its high mechanical strength and light weight. Pollen-polymer composites could form a new class of high strength, light-weight materials with biorenewable filler. Due to pollenâ??s unique architectures, these composites also provide insights to how filler microstructure may affect wetting and adhesion between phases. In this work, the effectiveness of pollen fillers in a thermosetting polymer is characterized as a function of pollen loading and surface treatment. We have found that an acid-base hydrolysis treatment of pollen can be used to tune mechanical, interfacial, and thermal properties in the thermoset. The acid-base treatment exposes and generates additional surface functional groups improving adhesion between pollen and the polymer matrix. Additionally, it reduces the pollen density versus native pollen to approximately 1.16 g/cc much lower than conventional fillers (talc, silica, calcium carbonate) and even many advanced fillers (carbon nanotubes, cellulose, wood flour). This is due to the elimination of intracellular material which makes the pollen hollow. Finally, the treated pollen is able to simultaneously stiffen and strengthen the thermosetting polymer due to its higher mechanical stiffness and the high degree of adhesion between the phases. Thus, pollen is an attractive filler for creating high strength,
light-weight materials with a sustainable plant sourced filler.