Synthesis, morphology, and thermal stability of nanoporous cyanate ester resins obtained upon controlled monomer conversion

Abstract

This paper focuses on the development of a straightforward and effective method for producing nanoporous thermosetting Cyanate Ester Resins (CERs) with controlled conversion of the reactive groups of cyanate monomer by varying polymerization temperature and duration of CER synthesis, followed by a simple extraction procedure. Using Fourier transform infrared spectroscopy, the conversion degree ranging from about 79% up to 96% was determined. DSC-based thermoporometry and scanning electron microscopy analyses evidenced the generation of nanoporous structures in the cross-linked CER films produced. The pore size distribution varied from ∼10 to 220nm with an average pore diameter of around 20–45nm and the porosity ratio was comprised between 2.8% and 7.4% for all the nanoporous CERs studied. It was established that the thermal stability of nanoporous CERs remained high enough and depended on the final conversion of cyanate groups in the partly cured CER networks.