Preparation And Properties Of Waterborne Polyurethane Modified By Graphene Oxide And Organic Silicon

Waterborne polyurethane(WPU)was a polyurethane with water as a dispersion medium,which had the advantages of safe use and environmental protection,but the poor tensile strength,tear strength and water resistance limit the application of WPU.In order to improve the performance defects of WPU and to give WPU some special properties,this topic used double modification technology to prepare functional graphene oxide/silicone modified waterborne polyurethane,and studied its structure and properties.The main research contents were as follows:Isophorone diisocyanate(IPDI),polytetrahydrofuran diol(PTMG2000),dimethylolpropionic acid(DMPA),1,4-butanediol(BDO),triethylamine(TEA),and hydrazine hydrate were used as the main material.A double-tailed dihydroxy silicone oil(DSE)was used as the modifier,and comb-like organic silicone modified waterborne polyurethane(DSE-WPU)emulsion was synthesized via the prepolymer dispersion method.The effects of reaction index R(R=n(NCO)/n(OH))value,hydrophilic monomer content on WPU structure and performance,and DSE content on DSE-WPU structure and performance were studied.The results showed that with the increase of DSE content,the particle size of DSE-WPU emulsion gradually decreased and the hydrophobicity became better.The crystallinity of the DSE-WPU film was reduced as well.Scanning electron microscope-energy spectrometer spectrum analysis indicated that DSE segments were easy to aggregate on the surface of the film,so that the enrichment rate of the silicon segment on the polymer surface was doubled;when the R value was 1.5,the hydrophilic monomer content was 5%,and the DSE content was 15%,the film with the best comprehensive performance could be obtained.The GO and DSE-modified WPU(GO/DSE-WPU)was prepared by mixing the self-made graphene oxide(GO)slurry and the DSE-WPU emulsion in a certain ratio by physical blending.The effect of GO content on the properties of DSE-WPU films was studied.The results showed that with the increase of GO addition,the wear resistance and thermal stability of GO/DSE-WPU film were improved;the maximum stress was increased from 6.5 N to 21.1 N;the static water contact angle increased from 112.8°to 130°,which indicated the increase of hydrophobicity.The UV-visible spectrophotometer results showed that with the increasing amount of GO addition,the UV transmittance of the GO/DSE-WPU film gradually decreased,which could be as low as 0,showing excellent performance of UV shielding.Aminated graphene oxide(AGO)was prepared using 1,10-decanediamine(DMDC)and GO slurry as raw materials.Then IPDI,PTMG2000,DSE,DMPA,BDO,TEA were used as raw materials,AGO was used as the post-chain extender,the DSE and AGO modified waterborne polyurethane(AGO-DSE-WPU)was prepared via the prepolymer dispersion method.The effect of AGO on its structure and properties was studied.The results showed that the copolymerization of AGO and DSE-WPU polymer could effectively improve the compatibility of AGO and DSE-WPU polymer.Compared with DSE-WPU film,the stress of AGO-DSE-WPU film increased from 19.5 N to 43.4 N.The elongation at break increased from 325.9%to 529.7%.The static water contact angle increased from 112.8° to 129.9°,and the hydrophobicity enhanced.Thermogravimetric analyzer analysis showed that the thermal stability of AGO-DSE-WPU film modified by AGO was significantly higher than that of DSE-WPU film.UV-visible spectrophotometer analysis showed that the UV transmittance of the AGO-DSE-WPU film can be reduced to 0,achieving complete shielding of UV rays,and the visible light transmittance could reach 80%,showing a good light transmission effect.