Study On Synthesis And Performance Of One Component Polyurethane Sealant

In this article,polyurethane(PU) prepolymer was prepared by polymerization of isocyanate and polyether,further using functional silane monomer reacted with PU prepolymer,then silane modified polyurethane prepolymer (SPU)was made,expansion and foaming can be fundamentally solved.The structure and molecular weight of SPU prepolymer was tested by fourier transform infrared spectroscopy(FTIR) and gel permeation chromatography(GPC), the tested results show that the functional silane monomer has successfully grafted to the main chain of PU prepolymer.The relation of NCO content of PU prepolymer and reaction time,choice of silane types,the effect of vulcanization accelerator on curing were studied, the research result shows that it closes or achieves devised theoretical value after diisocyanate and polyether glycol reacted 3.5 hours, sulfydryl silane can warmly react with isocyanate group and be easily controled. The effect of materials etc on SPU prepolymer property were studied.Latent curing agent modified Pu prepolymer also can solve expansion and foaming. The relation of NCO group content and curing condition was studied, when NCO group content below 2.3%, it has not expansion and foaming phenomenon when PU prepolymer curing.Dynamic curing was researched by FTIR, prepolymer completely cured when curing 20 hours.The relation between polyether polyols, latent curing agent dose and PU prepolymer mechanical property were studied.PU prepolymer storage stability was studied.PU sealant was produced by mix prepolymer,plasticizer and stabilizer etc.The effect of filler particle size,filler dose, coupling agent dose and plasticizer dose etc on PU sealant properties were studied.Differential scanning calorimetry(DSC), thermogravimetric(TG) and scanning electron microscope(SEM) were used to test PU sealant's microstructure.