New Aromatic tert‐Amines for Application as Photoinitiator Components in Photocurable Dental Materials

Abstract

A new type of aromatic tert‐amine with a bisphenol A (BPA) skeleton has been prepared and applied as a photoinitiator (PI) component for enhancing photosensitivity in formulations of visible light curable dental polymers. Two N,N‐dimethylamino (DMA) groups were incorporated into BPA diglycidyl ether to make 2,2‐bis[4‐(2‐hydroxy‐3‐(p‐N,N‐dimethylaminobenzoyloxy)propyloxy)phenyl]propane (DMABPA). One or two (meth)acryloyl groups were reacted with the hydroxyl groups of DMABPA to obtain the polymerizable, BPA‐based tert‐amines DMABPA‐1M (one methacrylate), DMABPA‐2M (two methacrylates), and DMABPA‐1A (one acrylate). The aromatic tert‐amines and ethyl p‐(N,N‐dimethylamino)benzoate (EDMAB) were combined with a camphorquinone sensitizer to form a photoinitiating system, which was applied in photopolymerizations of dental resin formulations, based on Bis‐GMA as a matrix prepolymer, by visible light exposure. The photoconversion of the formulations using the new aromatic tert‐amines as PIs was determined by the spectral changes in FTIR absorption intensities of methacrylate groups in cast films. High conversion (over 70%) resulted from photopolymerizations with (meth)acrylated DMABPA‐(1M, 2M, and 1A).magnified image

Can CQ Be Completely Replaced by Alternative Initiators in Dental Adhesives?

“…To overcome problems associated with yellowing, aging, toxicity, or incompatibility by the use of simple aromatic or aliphatic amines in conjunction with CQ, some polymeric or macromolecular photoinitiators like aromatic tert-amine with a bisphenol-A skeleton have been recommended 12) . In the same vein, the initiator CQ can be replaced by polymeric radical photoinitiators bearing the photosensitive CQ groups in the side chain 13) .…”

Tris(trimethylsilyl)silane as a co-initiator for dental adhesive: Photo-polymerization kinetics and dynamic mechanical property

“…Indeed, the amine free radical, formed after the hydrogen abstraction from amine by activated photosensitizer CQ, starts and guides the polymerization of methacrylate at a high rate. It has been widely reported that the type of amine directly affected the polymerization behavior [49,50]. It has also been reported that the amine systems undergo an acid-base reaction with acidic monomers and this reaction can affect the initiation of the polymerization process [51].…”

Synthesis and photolytic properties of 1,5-di-N,N′-dialkylaminoanthraquinones containing acryloyl groups

“…To overcome some of the shortcomings of photoinitiators and the amine co-initiators, studies devoted to the synthesis of polymeric photoinitiators [15][16][17], photoinitiators with covalently bound amines [18,19], and photoinitiators with a polymerizable (meth)acrylate functionality [20][21][22] had been undertaken. The resultant photoinitiators showed significant advantages over the corresponding monomeric photoinitiators, such as low odor and reduced toxicity.…”