Synergistic Composition for Inhibition of Polymerization and Color Stabilization of Styrene

The effect of the combination of the inhibitor 2,6-di-tertbutyl-4-dimethylaminomethylphenol and copper phthalocyanine on the efficiency of retardation reaction of styrene polymerization and its color stability was evaluated. The dilatometry method (test temperature T=120oC) showed that the time to formation of 2 % wt. polystyrene in the sample without inhibitor was 17 min, with the introduction of copper phthalocyanine in the amount of 1*10-6 % wt. was 33 min, while the introduction of inhibitor 2,6-di-tretbutyl-4-dimethylaminomethylphenol in the amount of 0.1 % wt. was 75 min. This fact indicates the appearance of a synergistic stabilizing effect. It was found that when combining 2,6-di-tretbutyl-4-dimethylaminomethylphenol with copper phthalocyanine (1*10-9-10-6 % wt.), the induction period before the beginning of the polymerization process increases about 5,7 times in comparison with the sample containing only copper phthalocyanine, and 2,5 times in comparison with the induction period provided individually by 2,6-di-tretbutyl-4-dimethylaminomethylphenol. The rate constant of styrene polymerization in the presence of a combination of the inhibitors 2,6-di-tretbutyl-4-dimethylaminomethylphenol and copper phthalocyanine decreased by a factor of 10 compared to the sample without inhibitor, by a factor of 5,5-7,5 compared to the sample containing only copper phthalocyanine, and by a factor of 2,6-3,5 compared to the sample containing only 2,6-di-tretbutyl-4-dimethylaminomethylphenol as an inhibitor, containing only copper phthalocyanine and 2,6-3,5 times compared to the sample containing only 2,6-di-tretbutyl-4-dimethylaminomethylphenol as an inhibitor, which confirms the fact of synergism effect. It was shown by UV-spectroscopy that when 2,6-di-tretbutyl-4-dimethylaminomethylphenol was used as an inhibitor during storage, the absorption intensity of styrene increased significantly, while the absorption intensity of samples containing only copper phthalocyanine and samples containing a composition of 2,6-di-tretbutyl-4-dimethylaminomethylphenol and copper phthalocyanine decreased sharply. It is also shown that the combination of 2,6-di-tertbutyl-4-dimethylaminomethylphenol and copper phthalocyanine leads to an increase in color stability of styrene approximately 1,6 times during storage, especially at very low concentrations of copper phthalocyanine still give very high efficiency, showing a synergistic stabilizing effect.