Interactions of visible light with polymers: photopolymerization and photodegradation
| Grant number: | 12/19656-0 |
| Support type: | Regular Research Grants |
| Duration: | May 01, 2013 - April 30, 2015 |
| Field of knowledge: | Physical Sciences and Mathematics - Chemistry |
| Principal Investigator: | Carla Cristina Schmitt Cavalheiro |
| Grantee: | Carla Cristina Schmitt Cavalheiro |
| Home Institution: | Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil |
| Assoc. researchers: | Miguel Guillermo Neumann |
Abstract
Photoinitiated polymerization is a process widely used in various practical applications, among which we can mention its use in dentistry (fillings and sealants), paints (drying and curing), and photomicrolithography (plates and printed circuits). In most of cases these works are developed in overall shape, and changes in formulations or procedures for obtaining specific characteristics of the polymers are empirically made. In our work we try to determine the fundamental physical and chemical parameters of elementary reactions involved in global processes to determine the overall polymerization mechanisms, to correlate well with the properties of materials and the polymerization conditions.Thus we are proposing to continue this type of studies with special emphasis on the elementary reactions that occur in the initiation of photopolymerization due to new initiators or mixtures in photopolymerization in the presence of microparticles. In all cases, the objective is the determination of the global mechanisms of polymerization reactions as a function of the rates of individual elementary processes. Likewise, the yields are determined for global polymerization and correlated with the stages of the photochemical quantum yields.On the other hand, physical and chemical properties of the polymers obtained will be studied and its dependence on the conditions of the polymerizations, through the influences of the polymerization rates in the structure of the materials.Meanwhile, processes that could lead to polymer degradation and photodegradation are being performed. These degradation studies include the studies of polymer films and solid solutions, in order to propose methodologies for degradation of polymeric materials potentially pollutants. In these cases, it is also made an approach to global mechanisms through the study of elementary processes. (AU)