Structural Effect on Thermal Cure and Property of Naphthalene‐Based Epoxies: Preparation and Characterization

Abstract Summary: Three naphthalene‐based epoxy monomers containing different size of linkages between two naphthalene rings: CC covalent bond ( 1 ), methylene ( 2 ), cycloaliphatic hydrocarbon derived from limonene ( 3 ) were prepared, and the effect of molecular structure on thermal cure behavior and property analyzed. Judged from the combination of the dynamic DSC and isothermal FTIR results, the cure reactivities were found to increase in the order of 1 > 2 > 3 when dicyandiamide was used in the curing systems, and the situation was slightly different in the monomer/4,4′‐methylenedianiline systems. The differences in reactivity as well as in thermal and mechanical properties for the epoxies can be attributed to the differences of configuration and conformational changes during the formation of crosslinked networks. These thermosets exhibited high glass transition temperature ( T g ) and had excellent thermal oxidative resistance. DSC thermograms for epoxy/dicyandiamide systems at a heating rate of 10 °C · min −1 . magnified image DSC thermograms for epoxy/dicyandiamide systems at a heating rate of 10 °C · min −1 .