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Interactions of visible light with polymers: photopolymerization and photodegradation

Grant number: 03/07770-4
Support type:Research Projects - Thematic Grants
Duration: April 01, 2004 - April 30, 2008
Field of knowledge:Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
Principal Investigator:Miguel Guillermo Neumann
Grantee:Miguel Guillermo Neumann
Home Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

Two types of processes related to polymers, in which the presence of visible light is important will be studied: i) light-induced polymerization (photopolymerization); and ii) the degradation of polymers by light (photodegradation). The research of light-initiated polymerizations in systems containing monomers and dyes, or other light absorbing compounds, is the aim of the photoinitiated polymerization field (which is being studied in our Research Group for over 10 years). The goal of this research is to obtain kinetic and thermodynamic data of the elemental reactions involved in the overall photopolymerization process. The knowledge of these data can be used to establish a reaction model, which could give an indication of what should be the reaction conditions (and formulations) that could lead to the optimization of the polymerization process. The research program includes studies with new photoinitiators and monomers (especially those related to practical applications). In addition, the photocuring of pre-formed polymers will also be studied, from the viewpoint of the kinetics and efficiency of the process. On the other hand, the study the photodegradation of polymers will be also undertaken. Similarly to what is described above, the main interest will lie in processes initiated by visible light, which limits the systems to coloured polymers. This means the presence of dyes, or other cromophores, in polymeric substrate. Again, the experimental procedures will consist in the determination of data corresponding to the elemental reactions involved in the overall photooxidation process, envisaging the proposal of a reaction model, which might lead to modifications to improve degradation. The research programs described above are related to real applications. Furthermore, in some cases, the studies will be directed practical applications. By instance, photopolymerizable dental resins and the processes of disposal of coloured polymers (used in food packaging) can be mentioned in this context. All these studies involve the use of advanced photochemical methods (the study of the reactions of excited states and transients), as well as polymer science techniques (reaction kinetics and properties of polymer based materials). (AU)

Scientific publications (7)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
NEUMANN, MIGUEL G.; SCHMITT, CARLA C.; GOI, BEATRIZ E. Thioxanthone Sensitized Photodegradation of Poly(alkyl methacrylate) Films. Journal of Applied Polymer Science, v. 115, n. 3, p. 1283-1288, FEB 5 2010. Web of Science Citations: 5.
NEUMANN, MIGUEL G.; SCHMITT, CARLA C.; HORN, JR., MARCO A. The Effect of the Mixtures of Photoinitiators in Polymerization Efficiencies. Journal of Applied Polymer Science, v. 112, n. 1, p. 129-134, APR 5 2009. Web of Science Citations: 11.
SANTOS, LAIS C.; POLI, ALESSANDRA L.; CAVALHEIRO, CARLA C. S.; NEUMANN, MIGUEL G. The UV/H2O2 - Photodegradation of Poly(ethyleneglycol) and Model Compounds. Journal of the Brazilian Chemical Society, v. 20, n. 8, p. 1467-1472, 2009. Web of Science Citations: 20.
POLI, ALESSANDRA L.; BATISTA, TATIANA; SCHMITT, CARLA C.; GESSNER, FERGUS; NEUMANN, MIGUEL G. Effect of sonication on the particle size of montmorillonite clays. Journal of Colloid and Interface Science, v. 325, n. 2, p. 386-390, SEP 15 2008. Web of Science Citations: 43.
NEUMANN, MIGUEL G.; SCHMITT, CARLA C.; CORREA, IVO C.; GOI, BEATRIZ E. The effect of using mixed initiator systems on the efficiency of photopolymerization of dental resins. Journal of the Brazilian Chemical Society, v. 19, n. 7, p. 1413-1417, 2008. Web of Science Citations: 5.
NEUMANN‚ M.G.; SCHMITT‚ C.C.; CATALINA‚ F.; GOI‚ B.E. The relation between the polymerization rates and swelling coefficients for copolymers obtained by photoinitiation. Polymer Testing, v. 26, n. 2, p. 189-194, 2007.
GIOVANA C. FERREIRA; CARLA C. SCHMITT; MIGUEL G. NEUMANN. Dependence of the thioxanthone triplet-triplet absorption spectrum with solvent polarity and aromatic ring substitution. Journal of the Brazilian Chemical Society, v. 17, n. 5, p. 905-909, Out. 2006.

Please report errors in scientific publications list by writing to: cdi@fapesp.br.