Reaction of polyvinyl alcohol with aluminium isopropoxide

The uncatalyzed and oxalic acid catalyzed modification of polyvinyl alcohol (PVA) with aluminium isopropoxide have been studied for reaction in a suspension of powdered PVA in boiling benzene. Isopropyl alcohol (IPA) formed during the reaction was removed by continuous distillation of an IPA-benzene mixture. The reaction was initially quite fast but slowed up rapidly and practically stopped when only 4–12% of the OH-groups had reacted. Thermogravimetric analysis (TGA) showed that products with 6.8 mole A1/100 mole VA exhibit a significant rise in decomposition temperature from 250 to 285°. The characteristics are attributed to the occurrence of vicinal OH-groups in PVA.