The ultraviolet activation spectrum of polycarbonate

Abstract

SynopsisPrevious work has shown that a polymeric phenyl salicylate arid a polymeric dihydroxybenpophenone are formed during the irradiation of polycarbonate with nonspectrally dispersed ultraviolet light. In the present studies the photodegradation of polycarbonate film has been investigated as a function of irradiating wavelength using spectrally dispersed light from a xenon arc between 2300 and 6300 b. Maximum changes in absorbance at 3200, 3600, and 4000 b were induced in the sample by irradiating wavelengths between 2800 and 2900 A. The wavelength sensitivity of an extruded sample of polycarbonate is compared with results obtained for a solution-cast thin film of the material. The results of the present study support the stepwise photodegradation mechanism of polycarbonate previously reported and suggest the possibility of an additional photodegradation process.

Photophysics

“…[8][9][10] These studies have produced "wavelength sensitivity spectra". These spectra are influenced by the type of reaction being monitored, the material structure and composition.…”

Paints and Coatings

“…UV radiation initiates photochemical aging. Weathering produces changes in gloss and color, cracking, blistering, loss of adhesion, and loss of flexibility; these parameters are used to evaluate aging [473][474][475][476][477][478]. ISO 2810 gives guidelines on how to perform natural weathering tests.…”

Photochemistry of Bisphenol-A-Based Polycarbonate: The Effect of the Matrix and Early Detection of Photo-Fries Product Formation

“…During the past three decades there have been a large number of papers written describing the photochemical decomposition of bisphenol A (BPA) based polycarbonate (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). From a review of the most recent literature published during the last 10 years, it is readily apparent that there are indeed a number of pathways which comprise the composite photodegradation process of polycarbonate.…”

“…Other possible pathways for photo induced decomposition which have been mentioned in the literature, but are not depicted in Scheme I, range from a side-chain photooxidation process to a radical ring-attack reaction. In addition, when wavelengths of light greater than 300 nm are used to induce the photodecomposition, there are a number of additional oxidation pathways, some of which are probably due to the presence of impurities, which are no doubt operative (13,(15)(16)(17)(18). The paper by Factor et al (10) describes the various possibilites.…”

“…Since both PC and PMMA are glasses at 32 0C, the difference between the results for DPC in the PMMA matrix and PC films must be a direct result of the incorporation of the aryl carbonate group into the polymer backbone.Fluorescence Analysis of PC and DPCOne of the most difficult problems associated with assessing the photodegradation of any polymer film is to be able to detect spectroscopic changes upon exposure to light for very short periods of time. Of course in the case of polycarbonate there have been a large number of papers which have been written over the years using spectroscopic evaluation to monitor the progress of the photodecomposition(1,4,8,10,11,13,(15)(16)(17)(18)(19).…”