WATER-ABSORPTION AND STATES OF WATER IN THERMOSETS FROM ETHYLENE-VINYL ALCOHOL COPOLYMERS AND DIANHYDRIDES

The crosslinking reaction of two ethylene-vinyl alcohol copolymers (EV OH) with 3,3',4,4'-tetracarboxybenzophenone dianhydride, pyromellitic carboxylic acid anhydride and -furyl)-3a,4,5,7-tetrahydroisobenzofuran -1,3-dione (Epiclon B-4400) as hardeners was carried out in solution. Different degrees of crosslinking were obtained. The crosslinked produ cts were characterized by spectroscopic techniques and thermal methods . The water absorption of these crosslinked materials was determined g ravimetrically as a function of time at room temperature. Differential scanning calorimetry was used to estimate the contents of three possi bles types of water absorbed by hydrophilic materials: frets water, bo und and freezable water and bound but non-freezable water.