Effects of Natural and Artificial Weathering on the Physical Properties of Recycled Poly(ethylene terephthalate)
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In accelerated weathering tests, specimens are exposed to higher radiation intensity, temperature and humidity than is likely under natural weathering in order to achieve rapid degradation of the polymer in a convenient short time. In the current work, a correlation between the two environments is attempted so that a prediction of lifetimes in the natural environment can be achieved. During aging, surface flaws are created due to the chain scission process. This is initiated by the absorption of ultra-violet light and directly affects visual appearance and impact strength. After natural weathering, the material shows only plastic deformation in an impact test. However, after artificial weathering to 5000 h of UV exposure, there is a decrease of 85% in impact strength. Colour change occurs at a high rate in the early stages of UV exposure. Beyond 2000 h of exposure, the colour change approaches a steady state and a correlation between the changes under natural and artificial weathering becomes apparent for a potential prediction of lifetimes. From the analysis including the specular component (SCI), taking surface roughening into account, 1 year under natural weathering was found to be equivalent to 25 days under accelerated weathering.
KeywordsUV degradation Poly(ethylene terephthalate) Weathering Recycling
The authors are grateful to Dr. Padmasari Kankanam Gamage for his technical support within the polymer laboratories at London Metropolitan University.
- 3.Achilias DS, Antonakou E, Roupakias C, Megalokonomos P, Lappas A (2007) Global Nest J 10, 1:114–122Google Scholar
- 8.Scheirs J (1998) Polymer recycling. Wiley, LondonGoogle Scholar
- 10.Thiele U (2006) In: Proceedings of the 9th international polyester recycling forum, WashingtonGoogle Scholar
- 11.Mancini S, Zanin M (1997) Polym Recycl 3(98):239Google Scholar
- 14.Saravanan D (2007) Autex Res J 7:53Google Scholar
- 17.Davis A, Sim D (1983) Weathering of polymers. Applied Science Publishers Ltd, LondonGoogle Scholar
- 20.Feller RL (1994) Accelerated aging: photochemical and thermal aspects. Research in conservation. The Getty Conservation InstituteGoogle Scholar
- 30.Krishnan S, Mitra S, Russell P, Benz G (1985) In: Proceedings of ACS symposium series 287. American Chemical Society, Washington, DCGoogle Scholar
- 36.Malanowski P (2009) Weathering of aromatic polyester coating. Ph.D Thesis. Eindhoven University of Technology, EindhovenGoogle Scholar
- 40.QUV accelerated weathering tester: operating manual (Q-Panel Lab Products, USA, 1997)Google Scholar
- 41.Precise colour communications: instruction manual (Minolta, Japan, 2007)Google Scholar