VISCOSITY CHARACTERISTICS OF SOME PARA-NONYLPHENOL FORMALDEHYDE NOVOLAC EPOXY-RESINS

Para-nonylphenol formaldehyde novolac epoxy resins with molecular weig hts between 640 and 3 150 were studied regarding the viscosity behavio ur. The estimation of both the intrinsic viscosity and the molecular w eight of the epoxidized resins resulted in a straight relationship bet ween these experimental parameters: eta! = k1 + k2M(n)BAR, where k1 = 137 dl/g and k2 = 99.2 . 10(-3) dl/g. Study of the flow behaviour of the molten epoxide resins allowed the measurement of the apparent shea r viscosity, the shear stress, the shift factor, the melt flow index, the consistency index, and the flow activation energy. The flow data, which were analysed both as a function of temperature and of the shear rate, led to the conclusion that para-nonylphenol formaldehyde novola c epoxy resins show a non-Newtonian rheological behaviour of pseudopla stic type.