Chain extension of ketonic resins

Chain extensions of cyclohexanone-formaldehyde (CF) and acetophenone-formaldehyde (AF) resins via their hydroxyl groups were studied. The chain extension was regulated by the ratio of hydroxyl groups/reactive reagents. Dimethyl dichlorosilane, phosphorus oxychloride, toluene-2,4-diisocyanate, phthalic anhydride, tetrahydro phthalic anhydride, trimellitic anhydride, 4,4′-oxydiphthalic anhydride were used as chain extender reagent. It has been shown that solubilites, melting point and molecular weight of extended resins depended upon the characteristics of chain extender reagents.