Cyanate ester coupling agents in aerospace industry. Catalytic properties of organometallic complexes and diazonium salts with complex anions in the curing reaction of cyanate ester coupling agents

Cyanate ester resin (CER) is the novel and prospective material. Thermal stability, low gas and moisture absorption, high dielectric properties, low outgassing, good resistance to radiation and radio transparency with dimensional stability are the key CER properties that make it the best candidate for the use in space apparatus manufacturing. During the impregnation process of high modulus carbon fibers by cyanate ester prepolymer at Prepreg Line-Type PLS-250-2F (Mikrosam, Makedonia) a premature reaction of polymerization on the heated metal rollers in the resin transfer sector of machine was observed. In this regard the catalytic effects of organometallic complexes containing ions of transition metals on kinetics of CER polymerization by using DMA and viscosimetric methods were studied. It is shown that a usage of stainless steel rollers results in a significant reduction of a lifetime of melt prepolymer. By the results of this research it is recommended to use the ceramic rollers instead, for example made from boron nitride. As a new type of catalyst for curing reaction of cyanate ester prepolymer, with the possibility of incorporation into the polymer network, diazonium compounds were first investigated. The obtained results include a new class of catalysts for curing of cyanate ester prepolymer into the category of a prospective type.