Miscible macromolecular antioxidants for polyethers |
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| Authors: | Michael M Coleman Marissa Mock Paul C Painter |
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| Institution: | 1. Department of Materials Science and Engineering , The Pennsylvania State University , University Park, PA, 16802;2. Division of Chemistry and Chemical Engineering , California Institute of Technology , Pasadena, CA, 91125 |
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| Abstract: | Oxidation reactions are one of the main reasons for the failure of polymeric materials. Antioxidants, compounds designed to protect against oxidation, must meet three main requirements for success: (1) an efficient antioxidative mechanism, (2) compatibility with the oxidizing polymer, and (3) permanence Within the oxidizing polymer. Common antioxidants are low molecular weight materials that can easily diffuse, leach, or evaporate from the polymer they are designed to protect. An increase in the molecular weight of the antioxidant not only decreases diffusion and volatility, but also decreases compatibility since most high molecular weight polymers will not mix. Selective sterically hindered phenolics, however, are concurrently antioxidants and “compatibilizers” through hydrogen bond formation. Carefully designed copolymers containing a small percentage of 2,6-diisopropyl-4-vinylphenol were found to mix intimately with two readily oxidizing polyethers and to protect them against oxidation. |
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