Abstract
A series of poly (o-vinylphenol), poly (m-vinylphenol) and poly (p-vinylphenol) were synthesized and their antioxidant effects on autoxidation of lard were examined by oven tests at 60°C. The results were compared with those for corresponding novolak type oligomers. Polyvinylphenols showed better antioxidant effects than the corresponding monomers, but were slightly inferior to BHT. Both the position of hydroxyl groups on aromatic rings and molecular weights of the polyvinylphenols were the factors determining the strength of this effects. The most effective molecular weights for poly (o-vinylphenol) and poly (p-vinylphenol) were from about 600 to 700. Polyvinylphenols were slightly inferior to novolaks in antioxidant effects. Of the polyvinylphenols, poly (o-vinylphenol) was best. These differences may possibly be due to cooperative intra-molecular hydrogen bonding between phenolic hydroxyl groups and the conformation of polymer chains in lard.
