Committee Members:

Dr. Paul A Kohl, Advisor, ChBE

Dr. Satish Kumar, MSE

Dr. Donggang Yao, MSE

Dr. Jared Schwartz, ChBE

Solid-State Chemical Recycling of Polymer Composites by Variable Frequency Microwave

ABSTRACT

Fixed frequency microwaves have been studied in various chemical transformation applications. A common issue seen with fixed frequency microwave is non-uniform heating and arcing. The current study highlights the use of variable frequency microwave (VFM) heating to achieve rapid thermal depolymerization of polymer composites. A wide range of additives were investigated to select the best performers for microwave heating at low energy. Carbon nanotubes, carbon nanofibers, carbon black, graphene, reduced graphene oxide were shortlisted for further investigation by incorporating the materials into different polymer matrices. The chemical and thermal influence of additives on polymer decomposition has been studied. The depolymerization of polyphthalaldehyde, polypropylene carbonate, two polyhydroxyalkanoates, and nylon 6 has been achieved. Additional experiment of polymer depolymerization with the combination of a photoacid generator and microwave-absorbing additive resulted in a reduction of total microwave energy required. This study demonstrates the use of VFM systems for chemical recycling and monomer recovery of select polymer matrices.