Examining the thermal degradation behaviour of a series of cyanate ester homopolymers

A series of thermally stable dicyanate monomers was prepared containing different thermally stable structural units, namely 2,2 '-bis(4-cyanatophenyl)propane, bis-4-cyanato-biphenyl, bis-4-cyanato naphthalene, 3,3 '-bis(4-cyanatophenyl)sulfide and 3,3 '-bis(4-cyanatophenyl)sulfone, was prepared and the identity of the products was confirmed by Fourier transform infrared and NMR spectral methods. The corresponding cyanate homopolymers were prepared and their properties were evaluated and compared. The composites were analysed for their thermal stability and thermal degradation kinetics. The series of homopolymers exhibit excellent thermal characteristics, e.g. relatively high glass transition temperatures of at least 215 degrees C, which were inversely proportional to the molecular weight between the crosslinks, high thermal decomposition temperature and high activation energies for the decomposition of cured resins. Determination of their limiting oxygen indices indicates that all the homopolymers are characterized as 'self-extinguishing' materials. (c) 2019 Society of Chemical Industry