Photolytic degradation of poly(olefin sulphones): A laser flash photolysis study |
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| Affiliation: | 2. Los Angeles County Department of Health Services, Emergency Medical Services Agency, Los Angeles, CA;3. US Public Health Service, Washington DC;4. Center for Traumatic Stress in Children and Adolescents, Department of Psychiatry, Allegheny General Hospital, Drexel University College of Medicine, Pittsburgh, PA;1. Department of Urology, Hospital of Vall Hebron, Autonomous University of Barcelona, Barcelona, Spain;2. Department of Urology, Fundació Puigvert, Autonomous University of Barcelona, Barcelona, Spain;3. Department of Urology, Hospital Clínic de Barcelona, University of Barcelona, Barcelona, Spain;4. Department of Urology, Hospital Parc Taulí, Autonomous University of Barcelona, Barcelona, Spain;5. Department of Urology, Hospital Bellvitge, University of Barcelona, Barcelona, Spain;6. Department of Urology, Hospital Germans Trias i Pujol, Autonomous University of Barcelona, Barcelona, Spain;1. Department of Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran;2. Department of Medical Physics, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran;3. Department of Medical Physics and Radiology, Faculty of Paramedical Sciences, Kashan University of Medical Sciences, Kashan, Iran;4. Biomedical Engineering and Medical Physics Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran |
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| Abstract: | ![]()
Poly(styrene sulphone) (PSS) and poly(butene-1 sulphone) (PBS) were irradiated in dilute solutions (dioxane and other solvents) with single 15-ns flashes of 265-nm light. Changes in the light scattering intensity (LSI) and the optical density (OD) after the flash were recorded with aerated solutions. It turned out that, with both polymers, the rate of LSI decrease (due to main-chain scission) is correlated to the rate of fragment diffusion. Optical density measurements with PSS revealed the existence of a short-lived species (λmax = 500 nm), probably a singlet excimer (τ < 25 ns) which is considered a precursor in the main-chain scission process. The existence of macroradicals, even after fragment separation, was inferred from an absorption band below 400 nm decaying with a half-life of 40 ms. In the absence of oxygen, main-chain scission and cross-linking occur simultaneously. Therefore, the presence of oxygen, which acts as a fixing agent for main-chain breaks, is prerequisite for using the photodegradation of poly(olefin sulphones) as a probe for studying the dynamics of polymers in solution. |
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