The use surface plasmon resonance to determine the optical parameters of UV-adhesive and control polymerization process

Abstract

Background: Ultraviolet adhesives are widely used in the manufacture of precision optical devices. It is known, that adding fillers to the glue reduces shrinkage after polymerization, reduces internal stresses, improves the reliability of the connection, and also allows you to control the optical properties of the connecting layer. By varying the amount and composition of the filler, you can change the refractive index of the compound, as well as improve the process ability of the compound due to faster polymerization. Material and methods: To measure optical parameters of the studied samples, we used the following devices: spectrometer Plasmon-71, spectrophotometer Fluorotestnano-2S, spectrophotometer UNICO 4802UV/VIS. As a source of UV radiation, we used semiconductor LED with the mean wavelength in its spectrum 406nm. As the objects for measurements, we used three samples, and each one represented the three-layered structure (glass-adhesive-glass) and, separately, three respective adhesives. All the glass elements of these samples were plates with the thickness 0.2mm and dimensions 20×20 mm from the glass with the refractive index n=1.61 with regard to vacuum. The sample differed between each other by composition of adhesives. Results: The reflective index for each glue was defined. The speed of glue polymerization was corresponded to difference on a result changes the coefficient of reflection too. The highest velocity of polymerization was observed for the adhesive 3 (2100 arb.un./min), the lowest one-for the adhesive 1(300 arb.un./min), and adhesive 2(1200 arb.un./min). Thus, the polymerization velocity of the adhesive 3 is 7times higher than that of the adhesive 1 and practically 2times higher than for the adhesive 2. adhesives 2 and 3 are polymerized more uniformly over the whole sample depth. The reflection coefficient at the minimum SPR was measured. This characteristic corresponds to the absorption of the glue. It is shown that the adhesive composition No. 3has the greatest absorption. Conclusion: The obtained results show that the SPR method is informative and can be applied for investigations and optimization of UV-adhesive composition. Introduction of organosilicon acrylates with high dispersion as impurities in these adhesives enables to increase the velocity of adhesive polymerization.

Studying the polymerization efficiency of photosensitive compositions by using the surface plasmon resonance method

“…1. Optical scheme of the device "Plasmon-71" [9]. 1source of light, 2collimation lens, 3polarizer, 4glass optical prism, 5lens, 6photodetector, 7studied sample.…”