Processing-dependent mechanical properties of solvent cast cyclic polyphthalaldehyde

Cyclic polyphthalaldehyde (cPPA) is a metastable polymer that undergoes rapid depolymerization in the solid state making it useful as a packaging and substrate material for transient electronics. Here, we report solvent based processing methods to fabricate free standing polymeric films and the mechanical properties of those films. Three solvents: dioxane (bp 101 °C), chloroform (bp 61 °C), and DCM (bp 40 °C) were explored for solvent casting of cPPA. Higher residual solvent concentrations were observed with an increase in the boiling point of the solvent, leading to large variations in the glass transition temperature (64–95 °C), as measured by dynamic mechanical analysis. Quasi-static tensile testing of solvent cast cPPA films gave an elastic modulus (2.5–3 GPa), tensile strength (25–35 MPa), and failure strain (1–1.5%) that vary depending on the type of solvent used.