Study On Preparation And Properties Of Polyurethane Modified By OMMT

Polyurethane elastomer(PUE) have an outstanding performance and theperformance was adjustable, and widely used in aerospace, textile, industry,agriculture and other industries. But it has a big internal, a bad heat resistanceand polar solvent resistance. Fillers could improve these performances. Inaddition to associate with its own structure, the performance of PUE is alsoaffected by the filler. Research on the relationship between structure and propertyof PUE has important implications for polymers development and use.Polyurethane pre-polymer was synthesized by4,4-diphenyl methanediisocyanate (MDI), toluene diisocyanate (TDI) and polyether glycol (PPG).Diethylenetriamine was used as chain extenders, epoxy resin as curing agent forthe preparation of polyurethane elastomer (PUE). And modified the PUE throughdoping the organic montmorillonite (OMMT) in situ polymerization,(OMMT/PUE) nanocomposites were prepared.The structure of the OMMT/PUE, layer spacing of OMMT, dispersion andstructure of OMMT in the matrix were studied by FT-IR, SEM, TEM, AFM andXRD. The tensile strength, elongation at break, storage modulus, glass transitiontemperature and loss factor of different hard segment of PUE were tested by anelectronic universal tensile testing machine and dynamic mechanical analysis.The volume resistivity, breakdown strength, dielectric constant, dielectric lossand water absorption of OMMT/PUE were tested and analysed by highimpedance meter and pressure resistance test.The results indicated that: the mechanical property of MDI-PUE wassuperior to that of TDI-PUE. The best mechanical property of PUE can beachieved when the content of hard segment was30wt%, the tensile strength was8.25MPa, elongation at break was403%. The layer spacing of OMMT in the substrate gets bigger, the OMMT uniform distributes when its content was lessthan4wt%. The addition of OMMT improved the properties of the PUE, tensilestrength of the OMMT/PUE was first increased and then decreased along withthe increasing of the OMMT content. When the content of OMMT was4wt%,the macanical performance was the best, at the same time the tensile strength was14.15MPa, the elongation at break was569%, the shear strength was8.0MPa,the storage modulus increased. The addition of OMMT improved the insulationperformance of composite materials. When the content of OMMT was2wt%, thevolume resistivity and the breakdown strength was the highest.