Rheological and morphological properties of some epoxy resins modified with polymer powders

The epoxy resins have been modified by mixing them with poly vinyl chloride (PVC). poly (vinylacetate - vinyl chloride - maleic anhydride) p-(VAc-CV-M A), polyacrilonitrile (PAN) and polyvinylalcohol (PVA). The mixture have be en morphologically and rheologically studieses. The morphology, of the mixt ures, with different solid-state concentrations, was done by optical micros copy. At low solid-state concentrations in the mixtures there was present a continuous phase made up of the liquid polymer with statistically, dispers ed powder, while at concentrations the mixtures presented a powdery, aspect . The mixtures rheological properties were evaluated with a rheometer havin g coaxial cylinders. At 0 shearing rate, the mixture viscosity grows with t he solid-phase concentration and decreases with the temperature increase, i n the following order: mixtures with PVA, PNA, PVC and p-(VAc-CV-MA). The f low activation energy, calculated both for 0 Shearing rate and for 50 Pa, i s relatively, constant for the same solid-phase concentration and is not de pendent on the polymer nature.