Polystyrene photooxidation. 2. A pseudo wavelength effect

Mailhot, Bénédicte; Gardette, J.

doi:10.1021/ma00042a013

Cited by 80 publications

(50 citation statements)

References 5 publications

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“…On the other side, it is well known that UV light and oxygen induce reactions in polymers that cause photo-oxidative degradation and it has been extensively described in the scientific literature [49,50,51,52]. After long UV irradiation of PS, which is absorbed by the styrene chromophoric groups, various oxidation photo-products are generated and a wide variety of mechanisms can be proposed.…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Evaluation of photo-induced crosslinking of thymine polymers using FT-IR spectroscopy and chemometric analysis

Bortolato

Thomas

Mcdonough

et al. 2012

Polymer

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Please cite this article as: Bortolato SA, Thomas KE, McDonough K, Gurney RW, Martino DM, Evaluation of photo-induced crosslinking of thymine polymers using FT-IR spectroscopy and chemometric analysis, Polymer (2012), doi: 10.1016/j.polymer.2012.09.007. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 2 ABSTRACTThe photo-induced immobilization of 4-vinylbenzyl thymine (VBT) and 4-vinylbenzyl triethyl ammonium chloride (VBA) copolymers has been investigated with the aid of grazing-angle specular-reflectance FT-IR spectroscopy. As irradiation time increases, changes in the structure of pendant thymine groups in the copolymer due to the crosslinking process result in shifts of the copolymer network's vibrational frequencies, as well as changes in numerous IR band intensities.In this work, chemometric methods have been applied to the FTIR data obtained while

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Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Evaluation of photo-induced crosslinking of thymine polymers using FT-IR spectroscopy and chemometric analysis

Bortolato

Thomas

Mcdonough

et al. 2012

Polymer

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“…In fact, our Fourier transform-IR spectra show the generation of carbonyl and hydroxy groups (Supplementary Figure S7), indicating that degradative photooxidation occurs during photoirradiation. [65][66] Thus, we assume that PS-related radicals such as PS and alkoxy radicals might recombine to produce dimers and further oligomers.…”

Section: Mechanism Of Srg Formationmentioning

confidence: 99%

Facile one-step photopatterning of polystyrene films

Ubukata

Moriya

Yokoyama

2012

Polym J

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The development of nano-and micropatterned materials is a key component of advanced nanotechnology. We report herein, a photo-based method for patterning general-purpose polymer films. Patterned ultraviolet (UV) light irradiation of a thin polystyrene film under controlled temperature generates surface relief structures by mass transfer from shaded to irradiated areas. The resulting surface relief structure can be arbitrarily erased by heating and reconstructed by patterned UV light irradiation, and this process is repeatable. This new method thus enables fabrication of dynamic reversible patterning structures from various general polymers.

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“…Gardette et al [20][21][22][23][24] have used micro-FTIR to study the photodegradation of polymers such as polystyrene, polycarbonates, and epoxy. A spatial heterogeneous distribution of the oxidation photoproducts has been observed for all these systems.…”

Section: Introductionmentioning

confidence: 99%

Probing photodegradation beneath the surface: a depth profiling study of UV-degraded polymeric coatings with microchemical imaging and nanoindentation

Michaels

Drzal

et al. 2007

J Coat Technol Res

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Photodegradation of polymer coatings generally involves photooxidation, resulting in the formation of oxidized products, chain scission, and crosslinking. On severe exposure to ultraviolet (UV) light in the presence of air, chemical degradation transforms into substantial changes in the physical and mechanical properties, leading to failures of the coatings. Systematic research by NIST on service life prediction of polymeric coatings indicates that the degradation of polymer coatings starts from the submicrometer degradation-susceptible regions at the surface and then grows in width and depth. Additionally, due to the oxygen diffusion effect and the attenuation of the UV light passing through the polymer, the degradation can be spatially heterogeneous. In this study, the changes with depth of the mechanical and chemical properties of a UV-exposed epoxy/polyurethane system were measured by nanoindentation and Fourier transform infrared spectroscopy (FTIR) microscopy using cross-sectioned specimens. Multilayers of epoxy/polyurethane samples were prepared by a draw-down technique. After curing, samples were exposed to the outdoors in Gaithersburg, MD, for four months. Crosssectioned slices of the exposed and unexposed samples, approximately 500 nm thick as-prepared by microtoming, were used for micro-FTIR imaging. Samples for nanoindentation were prepared by embedding the epoxy/polyurethane multilayers (both exposed and unexposed) in a molding compound, followed by microtoming and polishing the embedded films in the thickness direction. Micro-FTIR images clearly show that, for the outdoor exposed samples, substantial amounts of oxidation products are distributed in the 60 lm deep region from the surface to the epoxy bulk, decreasing in the center of epoxy region and increasing again toward the epoxy/urethane interface. Nanoindentation results also show that the modulus significantly increases in the first 60 lm region after UV degradation, and then decreases gradually with depth until a value slightly higher than the modulus of the undegraded epoxy is reached. The modulus rises again in the region near the epoxy/urethane interface. These similarities in the depth profiles of the properties indicate the linkage between the chemical degradation and the mechanical degradation. The study clearly shows that the spatial distribution of chemical species and mechanical properties is heterogeneous in the thickness direction for polymer coatings after UV degradation. It also demonstrates that cross-sectional analysis using nanoindentation and micro-FTIR imaging techniques is a useful method to characterize the mechanical and chemical depth profiles of polymer coating degradation.

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Polystyrene photooxidation. 2. A pseudo wavelength effect

Cited by 80 publications

References 5 publications

Evaluation of photo-induced crosslinking of thymine polymers using FT-IR spectroscopy and chemometric analysis

Evaluation of photo-induced crosslinking of thymine polymers using FT-IR spectroscopy and chemometric analysis

Facile one-step photopatterning of polystyrene films

Probing photodegradation beneath the surface: a depth profiling study of UV-degraded polymeric coatings with microchemical imaging and nanoindentation

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