Tuning the Thermal Properties of Polymethacrylates With Bicyclobutane Monomers

Developing novel yet recyclable plastics is necessary as society advances and increases reliance on materials. Using new classes of monomers enables the synthesis of unprecedented polymers for new applications. Here, we report copolymerization with bicyclo[1.1.0]butane monomers to make polymers with strained backbone units and analyze the thermal property changes based on the % incorporation of strained monomers. We discover that even low incorporation (5%–20%) of methyl bicyclobutane-1-carboxylate (MBC) to poly(methyl methacrylate) (PMMA) increases degradation temperature while decreasing glass transition temperature. Efficient depolymerization is achieved for copolymers with 20% or fewer MBC units under photothermal conversion. Other comonomers (2-methoxyethyl methacrylate and oligo(ethylene glycol) monomethyl ethyl methacrylate) are also copolymerized with MBC, and we assess the changes in their thermal properties, including lower critical solution temperatures (LCSTs). Our work expands the understanding of how the strained MBC monomer plays a role in copolymerization, thermal characteristics, and depolymerization of copolymers.