THERMOSETS OBTAINED BY CHEMICAL MODIFICATION OF POLY(EPICHLOROHYDRIN)WITH VINYL-TERMINATED AROMATIC CARBOXYLATES

Poly(epichlorohydrin) was modified in a high extent with several vinyl -terminated aromatic potassium carboxylates (4-(2-propenyloxy)benzoate , 4-(5-hexenyloxy)benzoate, 3-(2-propenyloxy)-2-naphthoate, 3-(5-hexen yloxy)-2-naphthoate and 2-(thioallyl)nicotinate) under solid-liquid ph ase-transfer conditions. Simultaneously with this substitution reactio n, cleavage and crosslinking side reactions occurred. The polymers obt ained were characterized by NMR, IR, elemental analysis, viscosimetry, size exclusion chromatography (SEC), differential scanning calorimetr y (DSC) and thermogravimetric analysis (TGA). Then, crosslinked materi als were obtained by curing mixtures of these linear polymers with 10% w/w of a radical initiator (dicumyl peroxide or 2,2'-azoisobutyronitr ile) on a DSC device. Finally, the thermal stability of the thermosett ing materials was tested by TGA, and the Arrhenius kinetic parameters were determined for dicumyl peroxide initiated crosslinking processes by calorimetric measurements.