Solvent-Free Synthesis of Layered Polymer Crystals

A new solvent-free synthetic process of layered polymer crystals as novel organic intercalation materials from (Z,Z)-muconic acid is described. This process includes the monomer synthesis, topochemical polymerization, transformation to poly(muconic acid), and intercalation. Alkylammonium muconate monomers were prepared by grinding muconic acid and the corresponding alkylamines in a ceramic mortar without any solvent. Topochemical polymerization of the alkylammonium muconates in the crystalline state was carried out under UV irradiation with a high-pressure mercury lamp or sunlight. Transformation from poly(alkylammonium muconate) to poly(muconic acid) was achieved by thermolysis at 250 °C under reduced pressure with a maintenance of their crystallinity. Intercalation of alkylamines into the polymer crystals proceeded by grinding poly(muconic acid) and alkylamine similar to the monomer synthesis. This process is a new type of polymer synthesis using green and sustainable materials and reactions as the solvent-free system.