The reaction of 4-tert-butyl phenylcyanate and aniline was analysed with the help of HPLC, MALDI-TOF and FT-IR. It was found that the main reaction products are aryloxy- and arylamino-substituted triazines. A number of side products were identified, which consist of triazine-, isourea-, guanidine- and cyanamide-structural elements. Three basic types of reactions are proposed: (i) stepwise addition of amino- and cyanate- or isourea- groups to form isourea- and guanidine-chains, (ii) ring closure to form aryloxy and arylamino substituted triazines and (iii) formation of cyanamide structures by abstraction of phenols from isoureas or amines from guanidines. The curing reaction of the liquid difuctional cyanate Primaset LeCy with several difunctional amines was characterized by DSC. All amines accelerate the curing process, where a large range of reactivities for the at least two-stage reaction was detected. Furthermore, glass transition temperatures of cured cyanate-amine copolymers above 200 degreesC were measured by DMA. Although the thermal behaviour is slightly worse than that of neat polycyanurates, high performance thermosets with easy and adjustable processing are obtained that are attractive for use as adhesives, casting or laminating resins. References: 14
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