Chair of Chemistry of Polymeric Materials, University of Leoben
Curing of polymeric materials using ionizing radiation is commonly used throughout the industry. Mainly those applications are UV curable coatings, furnishes or other applications which only require a surface near curing. Radiation curing offers significant advantages when low temperature processing is required to minimize product stresses or when no temperature may be applied such as curing dental polymers. Most commonly UV-Light or E-Beam technologies are used for such applications. However these methods all have the significant disadvantage of a low penetration depth. Therein lies the substantial potential of X-Ray and gamma ray curing which both can penetrate solid matter such as wood, inorganic composites or even metal. In this work the curing behavior of various resin compositions using a cationic curing mechanism was investigated by monitoring the curing kinetics of highly filled resin systems using Photo-DSC as well as FTIR spectroscopy. The focus was to determine an optimum initiator concentration and the required minimum radiation dose to achieve successful curing at a specific sample depth. Therefore samples were radiated, using composite phantoms of varying thicknesses, to decrease the incident radiation intensity to simulate deep sample layers. The adhesive layers could be thoroughly cured up to phantom thicknesses of 30 cm and yielded comparable results to thermally cured samples.
