Influence of crosslinking process on the mechanical behavior of Poly(Dimethylsiloxane) (PDMS)

In the present work was studied the influence of the crosslinking process on the mechanical behavior of a composite with a poly(dimethylsiloxane) (PDMS) matrix filled with inorganic particles, used as dental impression material. The material was crosslinked chemically and by exposition to 400kGy gamma radiation dose. The material properties, before and after crosslinking, were analyzed through physical chemical and mechanical tests and microscopic exam. The results showed that the gamma irradiation, as compared to chemical cure process, produced higher degree of crosslinking, better wettability, adjusted hardness and low fragility. However, the microscopic exam showed that the gamma irradiated PDMS presents, as compared with the chemical cure, a greater number of defaults which resulted from the large concentration of released gases. The results allowed us to conclude that gamma irradiation is an adequate process to crosslink the studied PDMS composite, since we can reduce the quantity of gases formed in this process. (author)