| Polyurethane sealant is a new type of sealant,which is formed by chemical reaction through chemical reaction after mixing of polyurethane prepolymer with curing agent,filler,polyol and antioxidant.Polyurethane sealant water resistance,oil resistance,high and low temperature resistance,good bonding performance,high tensile strength,chemical corrosion resistance,ductility can master the characteristics,is widely used for waterproofing,sealing glue.In polyurethane sealant performance influence factors on the basis of the analysis of its composition and the curing mechanism was an excellent comprehensive performance,polyurethane sealant,shorten curing time,improve their physical and mechanical performance,in order to meet the requirements of different working condition.Therefore,it is of great significance to study the mechanical properties of modified polyurethane sealant.The main content and research results of this paper include:?1?The curing time,hardness and physical and mechanical properties of the catalyst were tested,and the aging and alkali resistance were simulated.The optimum dosage was about 0.3‰of the catalyst for polyurethane sealant.CoMPared with the blank group,the physical and mechanical properties are greatly improved.?2?Design of powder filler CaCO3 content were 10%,20%,30%,40%and 50%,polyurethane sealant tensile bond strength increases with the increase of dosage of packing first after reduction,lightweight calcium content is about 30%when the physical and mechanical properties of the polyurethane sealant is better.?3?Based on the orthogonal experiment,the influence factors of the physical and mechanical properties of polyurethane sealants were catalyst>packing>temperature.Curing agent content at 0.03%,filler content at 25%,curing temperature at 30?the physical and mechanical properties of materials is the biggest improvement.?4?Using infrared spectrum,nuclear magnetic resonance?nmr?,x-ray fluorescence spectroscopy,gas chromatography-mass spectrometry and x-ray diffraction?xrd?method analyzes sealant composition,for mechanism analysis and formula to improve.?5?After high temperature aging simulation experiment and the aging of the polyurethane adhesive performance,tensile properties test when it is concluded that the ageing temperature greater than 80?,the service life of the polyurethane sealant has certain influence;the tensile bond strength of polyurethane sealant can be predicted rapidly and economically by the simulation of the relationship between temperature and the tensile bond strength after aging. |
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