MECHANICAL-PROPERTIES OF CARBON-FIBER-REINFORCED POLYESTER URETHANE HYBRID NETWORK COMPOSITES

Hybrid resins of unsaturated polyester/urethane were synthesized and c haracterized. Both the toughness and stiffness of the polyester were i mproved significantly by incorporating 20 wt% urethane. Unsaturated po lyester, styrene, and urethane showed good compatibility during blendi ng and probably formed a simultaneous interpenetrating network (IPN) d uring polymerization. The resultant IPN morphology possessed a unique glass transition temperature. This IPN morphology not only imparted gr eat fracture resistance to the otherwise brittle polyester, but also c hanged the fracture mode of new resin composites. The molecular weight of unsaturated polyesters did not have significant effect on the mech anical properties, but did exert an apparent influence on the fracture mode. During the cure process the side reaction, an amine reaction, c ould be suppressed by addition of suitable promoter and catalyst.