High-performance new photoinitiators for the preparation of functional photocurable polymer composites

Abstract

Obtaining dental composites with the desirable physical, mechanical and visual properties that polymerise according to an environmentally friendly cationic mechanism is a significant challenge. This is due to the lack of high-performance initiators for this type of material. This is because there are dental composites on the market that have, among other things, toxic monomers such as BisGMA. This paper presents five high-performance, completely new iodonium derivatives of biphenyl-based iodonium salts differentiated by push–pull structure of chromophores determined by positions of methoxy and trisilyl groups in the biphenyl rings. The influence of the methoxy grouping in the biphenyl ring on the push–pull effect was explained, and their spectroscopic and electrochemical properties were determined. For the first time, the possibility of using these compounds as high-performance initiators of cationic and radical polymerization was presented and described. New two-component initiator systems composed of iodonium salts and thiadiazole derivatives for preparing new-generation dental composites have also been proposed. The thiadiazole derivative was an very effective alternative to camphorquinone, commonly used in the dental industry. Completely new organic matrix compositions and a new curing mechanism have also been proposed by introducing monomers that polymerize according to radical and cationic mechanisms. As a result, dental composites with significantly reduced polymerization shrinkage compared to commercially available materials were obtained. Finally, a new photoinitiating system we have developed, makes it possible to obtain new composites that are an exciting alternative to materials currently used in dentistry.