Geomimetics for green polymer synthesis: highly ordered polyimides via hydrothermal techniques

摘要: Inspired by geological ore formation processes, we apply one-step hydrothermal (HT) polymerization to the toughest existing high-performance polymer, poly(p-phenyl pyromellitimide) (PPPI). We obtain highly-ordered and fully imidized PPPI as crystalline flakes flowers on micrometer scale. In contrast classical 2-step procedures that require long reaction times toxic solvents catalysts, HT allows for full conversion in only 1 h at 200 °C, nothing but hot water. Investigation of crystal growth mechanism via scanning electron microscopy (SEM) suggests aggregates form a dissolution–polymerization–crystallization process, which is uniquely facilitated conditions regime. A conventionally prefabricated polyimide did not recrystallize hydrothermally, indicating crystallization occur simultaneously. The obtained material shows excellent crystallinity remarkable thermal stability (600 °C under N2) stem from combination strong, covalent polymer backbone interchain hydrogen bonding.