Abstract
Three diamine-extended polyether urethanes were prepared and their photodegradation studied. We find that the structure of the urea, as well as the urethane linkage, is important in determining photodegradation and discoloration of the polymers. Both processes can be minimized by using aliphatic diisocyanates and aliphatic diamine chain-extenders that contain no activated hydrogen alpha to nitrogen. In particular, an N-aryl urethane and an N-benzyl urea polymer photodegrade at about the same rate, but the N-aryl urethane that can form an extended conjugated system discolors more rapidly. The mechanisms for photodegradation of aryl and alkyl urea groups involving initial N-C bond cleavage appear to be analogous to the accepted mechanisms for the corresponding urethanes. After initiation, degradation of the polyether poly(oxypropylene glycol) also contributes to loss in molecular weight.
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References
Beachell, H.C. and I.L. Chang. Photodegradation of urethane model systems.J. Polym. Sci., Part A-1, 10:503–520, 1972.
Brash, J.L., B.K. Fritzinger, and S.D. Bruck. Development of block copolyether-urethane intraaortic balloons and other medical devices.J. Biomed. Mater. Res. 7:313–334, 1973.
Bruck, S.D.,Blood Compatible Synthetic Polymers. Springfield, Illinois: Charles C. Thomas, 1974, pp. 77–78.
Craig, R.G., A. Koran, and R. Yu. Elastomers for maxillofacial applications.Biomater. 1: 112–117, 1980.
Fritzinger, B.K., S.K. Brauman, and J. Heller.Development of Materials for Cardiovascular Applications. Stanford Research Institute, Menlo Park, California, Annual Report No. 7, NHLI Contract No. H01-HB-3-2959, 1974, pp. 26–35.
Hummel, D.O., G. Ellinghorst, A. Khatchatryan, and H.-D. Stenzenberger. Segmented copolyethers with urethane and urea or semicarbazide links for blood circulation systems. I.Angew. Makromol. Chem. 82:103–127, 1979.
Monahan, A.R. The role of hydrogen bonding in the photochemistry of poly(t-butyl N-vinylcarbamate).Macromolecules. 1:408–413, 1968.
Osawa, Z., E.L. Cheu, and Y. Ogiwara. Study of the degradation of polyurethanes. II. ESR study on the photodecomposition of polyurethanes and ethyl phenylcarbamate.Polym. Lett. 13:535–542, 1975.
Schollenberger, C.S., and F.D. Stewart. Thermoplastic urethane structure and ultraviolet stability.Adv. Urethane Sci. Technol. 2:71–108, 1973.
Schultze, H. Uber den photochemischen abbau von polyurethanen.Makromol. Chem. 172:54–75, 1973.
Sharkey, W.H., and W.E. Mochel. Mechanism of photooxidation of amides.J. Am. Chem. Soc. 81:3000–3005, 1959.
Tarakanov, O.G., L.V. Nevskji, and V.K. Beljakov. Photodestruction and photooxidative destruction of polyurethanes.J. Polym. Sci., Part C. 23:193–199, 1968.
Trecker, D.J., R.S. Foote, and C.L. Osborn. Photochemistry of aryl carbamates.Chem. Commun. 1034–1035, 1968.
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This work was sponsored by the National Heart, Lung and Blood Institute, National Institutes of Health, under contract No. H01-HV-3-2959. The authors wish to thank Bruce K. Fritzinger for synthesis of the polymers and fabrication of the polymer films.
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Brauman, S.K., Mayorga, G.D. & Heller, J. Light stability and discoloration of segmented polyether urethanes. Ann Biomed Eng 9, 45–58 (1981). https://doi.org/10.1007/BF02584557
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DOI: https://doi.org/10.1007/BF02584557