(654f) Synthesis and Applications of Rapidly Degradable Polyphthalaldehyde Based Copolymers

Polyaldehydes are metastable materials at ambient conditions due to their typically low thermodynamic ceiling temperature (T_C), or the equilibrium temperature between monomer and polymer. Breaking one backbone bond in the polymer above the T_C will initiate total depolymerization down the polymer chain, converting back to aldehyde monomer. Polyaldehydes have yet to find a robust application in materials, because of their instabilities at ambient temperatures. Rather than a drawback, the low T_C phenomenon offers a unique advantage in the degradation of polymers due to the minimum activation energy required to degrade an entire polymer chain. This ability to rapidly convert to small molecules makes polyaldehydes well suited for applications in stimuli-responsive materials, transient technology, and sacrificial materials. Novel copolymers were synthesized using a variety of aliphatic and functional aldehydes with o-phthalaldehyde, which provides high molecular weight and stability. Reactivity behavior of aliphatic aldehydes correlates positively with the aldehyde’s hydration equilibrium constant (K_H), with electron-deficient aldehydes incorporating into copolymers at higher percentages. Higher incorporation of aliphatic aldehydes bring about lower molecular weight polymers. Results indicate that the polymerization conditions used in this study are above the T_C of the aliphatic aldehydes, but this does not prevent their copolymerization with phthalaldehyde. Post-polymerization modifications are performed to introduce functional groups that are incompatible with the polymerization chemistry. Applications towards transient technology are discussed.