Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5203519 | Polymer Degradation and Stability | 2009 | 4 Pages |
A soluble polyurethane was synthesized by a reaction of OH-telechelic, 1,2-rich, low-molecular-weight polybutadiene with toluene 2,4-diisocyanate. To the pendent vinyls of the polybutadiene blocks of the polyurethane, a sterically hindered phenolic antioxidant bearing a sulfanyl group (i.e., 6-sulfanylhexyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate) was added by a free-radical mechanism (in varying degrees of conversion). The self-stabilized polyurethane thus formed, bearing the antioxidant structures as side chains, was mixed in varying concentrations with the original (unstabilised) polyurethane and the thermo-oxidative stability of the mixtures was evaluated by DSC in air. The antioxidant effect of the polymeric stabilizer on the oxidative stability of polyurethane, expressed as the oxidation onset temperature, is approximately the same as that of a low-molecular-weight analogue, the commercial octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (Irganox 1076), as related to the same molar concentration of the phenolic moiety, but the former is superior to the latter due to its ability to persist in the matrix. In both cases, the onset temperature of oxidation increases with increasing mole ratio of the phenolic structure and the total butadiene units in the mixture.