Study On The Curing Kinetics Of UV Curing System

Curing kinetics is one of the important approaches to study UV curing progress. The purpose is to obtain the curing ratio of the UV curing system and the proportion of the solidified part at a specific time or temperature, So as to find the best curing condition and increase the curing ratio. At present, the Differential Photocalorimetry and the Real-time Infrared Spectroscopy etc. are the main approach to study the ultraviolet curing kinetics. But there’s a few report to study the ultraviolet curing kinetics from the perspective of Rheology, and to derivate a kinetic model by the means of rheological experiment.The free radical polymerization reaction which initiated by ultraviolet was studied with a method based on rheological. Changes of G’(dynamic modulus) in every stage of curing process were real-time monitored by a rheometer equipped with UV curing accessory. Curing kinetics was studied after analysis the change of UV system’s internal structure during the curing process. The influence of photo-initiator, monomer, pre-polymer, active amine and intensity of light etc. on the curing process of UV curing system were discussed. After associating β (rheological conversion rate) with G’(dynamic modulus) and curve fitting, a nonlinear kinetic equation was set up to describe the cure reaction.The results show that the UV curing process could be characterized by the method of real-time monitoring the changes of G’(dynamic modulus) in every stages of curing process. G’-t curve of UV curing process is following the trends of the S curve of free radical polymerization. The varieties and contents of Photo-initiator, monomer, pre-polymer, active amine and the intensity of light have affect on the UV curing process. After fitting the β-t curve and derivation it, the relationship between dβ/dt and time could be obtained. The curing ratio of UV curing system could be characterized. Three mathematical fitting models were discussed in the paper. The test data of experiment could be better fitted by the mathematical fitting model with correction factor.