MORPHOLOGY AND PROPERTIES OF NOVEL COPOLY(ISOCYANURATE UREA)S FORMED BY REACTION INJECTION-MOLDING

Novel copoly(isocyanurate-urea)s have been produced by reaction inject ion moulding (RIM). The materials were formed from approximately 2:1 w eight ratio of polyisocyanate to polyoxypropylene polyamine in the pre sence of an organic trimerization catalyst. In some cases an aromatic diamine chain extender was also used. The effects of the polyether pol yamine functionality and the incorporation of aromatic diamine chain e xtenders on the morphology and properties of the copoly(isocyanurate-u rea)s were studied using the SAXS, TEM, d.m.t.a. and tensile stress-st rain techniques. The RIM materials were stiff plastics with room-tempe rature Young's moduli between 1.5 and 0.7 GPa, depending on the morpho logy. Development of morphology is a result of competition between pol ymerization kinetics, chemical gelation and (micro)phase separation. M aterials with an isotropic, co-continuous morphology with a size-scale of approximately 100 angstrom had higher moduli than materials contai ning isolated glassy particles of approximately 1 mum in size. Correla tions between morphology and dynamic mechanical-thermal and tensile st ress-strain properties of a systematic series of copoly(isocyanurate-u rea)s have been established.