Thioxanthone Sensitized Photodegradation of Poly(alkyl methacrylate) Films
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
20/10/2012
20/10/2012
2010
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Resumo |
The thioxanthone-sensitized photodegradation of poly(alkyl methacrylate) films [alkyl = methyl, ethyl, butyl, and hexyl] was studied using near UV-vis light. The photooxidation process continued even after the total consumption of the sensitizer, possibly due to the excitation of the ketyl groups formed during the first stages of the process. The rate of oxidation, as well as the formation of hydroxy, peroxy, and ketyl groups was faster for polymers with larger ester groups. The decrease of the molecular weight of the degradated polymers was also larger for the hexyl substituted polymer. The side-chain size effect was attributed to the larger amount of secondary hydrogens available for abstraction by the triplet state of thioxanthone, present in the larger ester groups. The lower glass transition temperature of the hexyl substituted polymer allows a better diffusion of oxygen to the deeper layers of the films that also contributes to the faster photodegradation rate. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 1283-1288, 2010 FAPESP, Brazil[03/07770-4] Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) FAPESP, Brazil[05/03692-4] Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) CNPq[471310/2006-9] Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) FAPESP Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) |
Identificador |
JOURNAL OF APPLIED POLYMER SCIENCE, v.115, n.3, p.1283-1288, 2010 0021-8995 http://producao.usp.br/handle/BDPI/31885 10.1002/app.30758 |
Idioma(s) |
eng |
Publicador |
JOHN WILEY & SONS INC |
Relação |
Journal of Applied Polymer Science |
Direitos |
restrictedAccess Copyright JOHN WILEY & SONS INC |
Palavras-Chave | #polymer photodegradation #sensitized photodegradation #poly(alkyl methacrylate) films #PHOTOOXIDATIVE DEGRADATION #ULTRAVIOLET-IRRADIATION #POLYMERS #BENZOPHENONE #POLYETHYLENE #POLYSTYRENE #TRANSITION #MECHANISM #Polymer Science |
Tipo |
article original article publishedVersion |