A study has been made of the effect of relative humidity, anatase titanium dioxide content, and uv-stabilizer on the photodegradation of nylon 66 and polyethyleneterephthalate yarns exposed to pyrex/clear glass filtered xenon-arc radia tion, at 20, 50, and 80% RH, in the Weather-Ometer, and to sunlight behind single, strength-window glass at approxi mately 20% RH. Analysis of loss of tensile properties has shown that a high relative humidity level in the Weather- Ometer has significantly accelerated photodegradation of both fibers. X-ray diffraction analysis, performed on several nylon yarns, has indicated a higher degree of crystalline perfection after irradiation at 80% RH, giving a possible ex planation for accelerated loss of tensile properties. Results of xenon arc and filtered sunlight irradiations at comparable RH levels (20%) have shown that a difference in RH does not contribute to the poor correlation found between Weather- Ometer and outdoor exposures. Titanium dioxide significantly accelerated photodegradation of nylon and was the main cause of breakdown of polyester exposed to filtered sunlight. Photosensitization of titanium dioxide was less apparent in the Weather-Ometer. The protective effect of the uv-stabilizer added to several nylon yarns was more apparent during outdoor exposure than during xenon-arc irradiation.
Alvino, W.M. , Ultraviolet Stability of Polyimides and Polyamide Imides, J. Appl. Polymer Sci.15, 2123-2140 (1971).
2.
Anton, A., Determination of Hydroperoxides in Ultraviolet Irradiation of Nylon 66, J. Appl. Polymer Sci.9, 1631-1639 (1965 ).
3.
Carlsson, D.J. and Wiles, D.M., The Photodegradation of Polypropylene Films. III: Photolysis of Polypropylene Hydroperoxides, Macromolecules2, 597-606 (1969).
4.
Carlsson, D.J. and Wiles, D.M., Photooxidation of Polypropylene Films. IV. Surface Changes Studied by Attenuated Total Reflection Spectroscopy, Macromolecules,4, 174-179 (1971 ).
5.
Coblentz, W.W. , Correlation of Bioclimatic Ultraviolet and Total Solar Radiation in Washington, D. C., 1941-1948, Bull. A mer. Met. Soc.30, 204-207 (1949).
6.
Day, M. and Wiles. D.M., Photochemical Degradation of Polyethylene Terephthalate. Part I: Irradiation Experiments with Xenon and Carbon Arc, J. Appl. Polymer Sci.16, 175-189 (1972).
7.
Day, M. and Wiles, D.M., Photochemical Degradation of Polyethylene Terephthalate. Part III: Determination of Decomposition Products and Reaction Mechanism, J. A ppl. Polymer Sci.16, 203-215 (1972).
8.
Dean, J.D., Fleming, C.M., and Connor, R.T., Effects of Unfiltered Carbon Arc Light in Accelerated Weathering of Cotton and Other Textiles, Textile Res. J., 22, 609-616 (1952).
Deanin, R.D. , et al., Mechanism of Ultraviolet Degradation and Stabilization in Plastics, Polymer Eng. Sci.10 (4), 228-234 (1970).
11.
Egerton, G.S. , Photosensitizing Properties of Dyes and White Pigments, Nature204, 1153-1155 (1964 ).
12.
Egerton, G.S. and Morgan, A.G., The Photochemistry of Dyes Part IV: The Role of Singlet Oxygen and Hydrogen Peroxide in Photosensitized Degradation of Polymers, J. Soc. Dyers Colourists87, 268-277 (1970).
13.
Fitton, S.L. , Howard, R.N., and Williamson , G.R., Photochemical Degradation of Thermoplastics, Brit. Polymer J.2, 217-224 (1970).
14.
Galemba, F.J. and Guillet, J.E., Mechanisms of Ultraviolet Stabilization of Polymer Films, J. Paint Technol.41, 315-320 (1969).
15.
Gates, D.M. , Spectral Distribution of Radiation at the Earth's Surface, Science151 (3710), 523-529 (1966).
16.
Kamal, M.R. and Saxon, R., RecentDevelopments in the Analysis and Prediction of the Weatherability of Plastics , Appl. Polymer Symp. No. 4, 1-28 (1967).
17.
Lock, L.M., A Study of Some Factors Affecting the Photodegradation of Nylon and Polyester Yarns, Unpublished Master of Science Thesis, University of Guelph, 1972.
18.
Lock, L.M., Frank, G.C., and Stevens, J.R., A Study of Some Factors Affecting the Photodegradation of Textile Yarns. Part I. The Spectral Distribution of Sun-Sky and Xenon Arc Radiation, Textile Res. J.43, 483488 ( 1973).
19.
Marcotte, F.B. , et al., Photolysis of Polyethyleneterephthalate , J. Polymer Sci.A-15, 481 - 501 (1967).
20.
McLaren, A.D. and Rowen, J.W., Sorption of Water Vapour by Proteins and Polymers, J. Polymer Sci.7, 289324 (1969).
21.
McMahon, W., Berdsall, H.A., Johnson, G.R., and Comelli, G.T., Degradation Studies of PET, J. Chem. Eng. Data4 (1), 57-79 (1959).
22.
Moore, R.F., Photochemical Degradation of Polyamides, Polymer4, 493-513 (1963).
23.
Morton, W.E. and Hearle, J.W.S., "Physical Properties of Textile Fibers," Manchester and London, Butterworths, 1962.
24.
Neiman, M. B., Ed., "Aging and Stabilization of Polymers," New York, Consultants Bureau, 1965.
25.
Nielsen, L.E. , "Mechanical Properties of Polymers," New York, Reinhold, 1962.
26.
R05 Stepwise Regression Computer Program, BMD Series of Statistical Programs, University of California, July, 1972.
27.
Schefer, W. , The Photochemical Breakdown of Polyester Fibers , Textil-Rundschau13 (6), 336-346; Ibid.13 (7), 396-411 (1958). N. R. C. Technical Translation812.
28.
Sharkey, W.H. and Mochel, W.E., Mechanisms of Degradation of Amides, J. Amer. Chem. Soc.81, 3000-3005 (1959 ).
29.
Singleton, R.W., Kunkel, R.K., and Sprague, B.S., FactorsInfluencing the Evaluation of Actinic Degradation of Fibers. Part I, Textile Res. J.35, 228-237 (1965).
30.
Singleton, R.W. and Cook, P.A.C., FactorsInfluencing the Evaluation of Actinic Degradation of Fibers, Part II, Textile Res. J.39, 43-49 (1969).
31.
Stair, R., The Measurement of Solar Radiation with Principle Emphasis on the UV Component , Int. Air Water Poll. J.10, 665-688 (1966).
32.
Subramanian, R.V.R. and Talele, T.V., Photodegradation of Nylon 6, Textile Res. J.42, 207-214 (1972).
33.
Stephenson, C.V. et al., Ultraviolet Irradiation of Plastics. I. Degradation of Physical Properties, J. Polymer Sci.55, 451-464 (1961).
34.
Taylor, H.A. , Tincher, W.C., and Hamner, W.F., Photodegradation of Nylon 66: Phototendering by 'I iO2, J. A ppl. Polymer Sci.14, 141-146 (1970).
35.
Thekaekara, M.P., Proposed Standard Values of the Solar Constant and the Solar Spectrum, J. Env. Sciences13, 6-9 (1970).
36.
Tweedie, A.S. , Mitton, M.T., and Sturgeon , P.Z., How Reliable are Artificial Light Sources for Predicting Degradation of Textiles, Textile Chem. Col.3 (2), 27-39 (1971).
37.
Wall, M.J., A Study of the Spectral Distributions of Sun-Sky and Xenon Arc Radiation in Relation to Degradation of Some Textile Yarns, Unpublished Master of Science Thesis, University of Guelph, 1970 .
38.
Wall, M.J. and Frank, G.C., A Study of the Spectral Distributions of Sun-Sky Xenon Arc Radiation in Relation to Degradation to Some Textile Yarns. Part I: Yarn Degradation, Textile Res. J.41, 32-38 (1971).
39.
Wall, M.J., Frank, G.C., and Stevens, J.R., A Study of the Spectral Distribution Studies, Textile Res. J., 41, 38-43 (1971).
40.
Winslow, F.H. and Hawkins, W.L., SomeWeathering Characteristics of plastics, Appl. Polymer Symp. No. 4, 29-39 (1967).
