Water soluble polymers from Diels‐Alder adducts of abietic acid as paper additives

The diacids resulting from Diels-Alder reaction between abietic acid and acrylic acid or maleic anhydride were used together with adipic acid to prepare water soluble poly(amide)s or poly(amide-imide)s. An experimental program was worked out with the aim to find the weight ratios between the acid reactants that ensure water solubility of the resulting polymers. The obtained soluble polymers were reacted with epichlorohydrin to acquire substituted polymers, also water soluble, but which will crosslink by heating in the solid state (thermosetting polymers). They can be used as wet strength and sizing agents in the papermaking. Water solubility is required for these utilizations in paper chemistry.