Structure?Property relationships in nanocomposites based on cyanate ester resins and 1-heptyl pyridinium tetrafluoroborate ionic liquid

摘要

Novel thermosetting systems based on cyanate ester resins (CERs) have been created through the polycyclotrimerization reaction of dicyanate ester of bisphenol E (DCBE) in the presence of different amounts of 1-heptyl pyridinium tetrafluoroborate [HPyr][BF4] Ionic Liquid (IL). A significant accelerating effect on the curing kinetics of DCBE was found by FTIR analysis. The reaction mechanism for the [HPyr][BF4]-catalyzed polycyclotrimerization of DCBE was newly proposedviathe formation of a [CN]δ+–[HPyr]δ?complex as a key intermediate. Structure–properties relationships for the thermostable CER/IL networks were investigated by using DSC, DMTA, dielectric spectroscopy, tensile testing, quasi-dc measurements (I-Vcharacteristics), and TGA. All the nanocomposites showed excellent thermal stability up to 300?°C, indicating the formation of a densely crosslinked network even at high IL content (40?wt%), and they could be used at high temperatures above theirTgwithout significant thermal degradation. Nanoscale phase separation led to the creation of ionic channels within the CER matrix to ensure photosensitivity properties.