No abstract

Antioxidant-free GR-S is highly unstable toward oxygen. The inhibiting effect of phenyl-β-naphthylamine at a concentration as low as 0.001 per cent could be detected, and the effect became appreciable at an antioxidant content of 0.1 per cent. The activity of antioxidants at such low concentrations is difficult to explain except on the basis that the antioxidant functions as a chain terminating agent. Under the usual conditions of processing or storage, the concentration of antioxidant commonly employed in production of GR-S, 1.25 to 1.5 per cent, appears entirely adequate. When used as criteria of polymer stability, satisfactory correlation was noted between oxygen absorption and deterioration of physical properties.