The detection items for initiators include type, residual amount, purity, stability, and polymer compatibility. Commonly used detection techniques include gas chromatography, high-performance liquid chromatography, mass spectrometry, spectrometry, and electrochemical methods.
Gas chromatography-mass spectrometry (GC-MS) is an important method for determining initiator content, suitable for determining the content of photoinitiators in radiation-cured coatings. This method is also used to simultaneously determine nine photoinitiators, including benzophenone and 4-methylbenzophenone, in food packaging materials. The detection method was established by optimizing sample pretreatment conditions and GC-MS detection conditions.
Initiator concentration titration is a key quality control step in polymer synthesis and chemical production. Peroxide initiator content is determined using iodometric titration or cerium sulfate titration, while azo initiator concentration analysis is based on the decomposition characteristics of diazo groups.
The performance evaluation of macromolecular photoinitiators includes photoinitiated polymerization kinetics, thermogravimetric analysis, and coating performance testing. For example, the maximum reaction rate of PTF photoinitiator initiating the polymerization of trimethylolpropane triacrylate is 0.037 s⁻¹. Thermogravimetric analysis shows that its thermal stability is higher than that of 1173 photoinitiator. Coating performance testing shows that the effect is better when the amount of PTF is 4% of the mass fraction of the curing system.
