|Author(s)||Collection number||Pages||Download abstract||Download full text|
|Shybanov S. V., Shybanov V. V., Slobodianyk V. H.||№ 2 (57)||26-35|
The article describes the methods of synthesis of new photoinitiators of radical polymerization of acrylic monomers and photopolymerizable composite materials. The synthesized substances are characterized by the presence of two types of energy-sensitive groups in their composition, namely: thermally stable peroxide-containing fragments which containing -O:O-group and absorbing UV-chromophore group (aromatic ketones, colorants, azo-, diazocompounds). Such photoinitiators with a wide spectrum of UV radiation can be used for the two-stage initiation of radical polymerization: in the initial stages, as photoinitiators, and then in deep stages for the complete stitching of unsaturated monomers by thermolysis of peroxide groups.
Synthesis of peroxide-containing photoinitiators has been carried out by acylating alcohols or hydroperoxides with chlorohydrides of benzoyl benzoic acid in the presence of organic amines in an inert, light-flowing solvent medium. The completeness of the reaction has been monitored by thin-layer chromatography on the Sulyfol 254 plates. The interaction of the potassium salt of benzoyl benzoic acid and bromo-derivative peroxide has been carried out at a temperature of up to 5°C in a medium of dimethylformamide. Solid products are crystallized in a mixture of diethyl ether-hexane
The kinetics of photoinitized polymerization of monomers has been studied by dilatometric method. It has been shown that the effectiveness of initiation of polymerization of MMA for the studied photoinitiators in all cases is greater than that of styrene. The stitch rate has been determined by the Charlesby method.
Peroxide compounds containing a thermoplastic peroxide group coupled with a chromo-morphine UV absorbing fragment are effective photoinitiatory radicals of radical polymerization. The comparison of the initiating activity of the synthesized peroxidines indicates their higher activity in comparison with benzophenone. These compounds are also capable of thermolysis at temperatures higher than 90°C, which allows them to be considered as effective thermo-photoinitiators, which are capable of gradually initiation of radical processes.
Keywords: photoinitiators, organic peroxides, photodecay, kinetics of polymerization, light sensitivity, thermometric measurements.