Preparation Of Alcohol-soluble Organic/inorganic Hybrid Heat-resistant Adhesive

Organic adhesives are usually based on many kinds of high polymer matrix,and have excellent bonding properties at room temperature.But the organic matrix will crack in high temperature environment and result in the adhesive structure failure.The silicate and phosphate are the main body of inorganic adhesives.The inorganic adhesives have excellent heat resistance and high bonding strength.The organic/inorganic hybrid adhesive is prepared based on the respective advantages of these two types of adhesives to achieve both excellent heat resistance and good bonding properties.Since the high temperature resistant phosphate adhesives is water-based which can be used at temperatures above 1000°C,and the water solvent is corrosive to certain materials(such as spacecraft radome materials),and it is easy to unstick for the adhesion of hydrophobic materials,therefore the preparation of a non-aqueous phosphate adhesive has its practical application significance.In this paper,some metal oxides(M_x O_y),such as zirconium dioxide,chromium oxide and copper oxide,etc.,and common organic solvents are added by chemical modification in the phosphate crystals which have removed the water solvent.As shown in Figure 2-1,a chain bridge of-O-M-O-is formed so that the metal atoms are introduced into the phosphate structure,and it makes the solubility of inorganic salt and organic solvents as close as possible in order to promote the dissolution.Taking into account the compatibility,safety of solvents and boiling point of solvents,etc.,the ethanol is selected as the solvent to prepare the alcohol-soluble phosphate adhesive.Three kinds of hybrid adhesive based on the alcohol-soluble phosphate resin are prepared by adding phenolic resin,epoxy resin and silicone resin respectively.Through the comparison of compatibility,shear strength,curing temperature,infrared spectra and thermal weight loss,the reason which causes the difference in performance is analyzed,and the phenolic resin added hybrid adhesive is confirmed to have the optimal comprehensive performance.The curing behavior of the adhesive is studied by differential scanning calorimetry.The content of phenolic resin has little effect on the curing process of the adhesive,but the shear strength test showed that it has a great influence on the adhesive properties.The effects of phenolic resin content and temperature on the mechanical properties,heat resistance,crystal structure and microstructure of the adhesive are analyzed according to the results of infrared spectrum,X-ray diffraction and scanning electron microscopy.When the phenolic resin is 30phr,the adhesive will possess the best high-temperature bonding performance.The results show that the mechanical strength of the adhesive declines after being boiled in water.The causes which make the changes in performance of adhesive are analyzed by means of infrared spectrum,X-ray diffraction and scanning electron microscopy.