Synthesis Of UV-curing Organic-inorganic Hybrid Materials With High Heat Resistant Property Via Sol-gel Reaction

Sensor technique is one of the most important technologies during the information age. Sensor is the basement of the technological revolution and information society. Fiber optical sensor is paid more and more attention due to the wide application, such as power transmission system, petrochemical industry, biochemical engineering, aeronautics and space industry, environment engineering and national security et al. The properties of fiber optical sensor are more vital while is used in environmental extremes. The properties are depended on the coating of the fiber.So the thesis was focused on the coating for optical fiber. First and foremost, the oligomer of polyurethane acrylate (PUA) was synthesized based on polypropylene glycol (PPG),2,4-toluene diisocynate (2,4-TDI) and hydroxyethyl acrylate (HEA). Content of isocyanate group in polyurethane acrylate prepolymer was tested with acetone dibutylamine method. Thermogravimetic analysis (TGA) showed that the oligomer synthesized by PPG2000exhibited the best thermal stability and the initial decomposition temperature (IDT) was about280℃. There were two glass-transition temperature (Tg),29.7℃and104℃respectively, appeared in the curve of differential scanning calorimeter (DSC). They respectively represented the soft segment and rigid part.Secondly, polyurethane acrylate was blended with epoxy acrylate (EA) with different ratios. The hardness test, curing degree test and TGA all illuminated the system with the ratio of PUA:EA of2:1showed the best thermal property.Last and not the least, the silica sol was produced by sol-gel reaction with tetraethoxysilane as the silicon resource, acid or base as catalyst and deionized water-ethanol as medium. Next, the silica sol was charged to the PUA and EA system with different ratios. Silane coupling agent connected organic part and inorganic part with chemical bond to obtain hybrid materials. The graphs from field emission scanning electron microscope (FESEM) showed the diameter of silica particles prepared by acid as catalyst was about80-100nm and KH-570was perfectly avoid the agglomeration and the particles was dispersed well in resin. According to TGA, the hybrid material made from the ratio of TEOS:(PUA+EA) of0.4:1started to lose weight at about350℃. Meanwhile, the thermal decomposition temperature was arriving at143.8℃, was approximately70℃higher than pure resin. The silica particles showed perfect crystallinity.