The Preparation And Property Of Waterborne Polyurethane Grouting Material

High-performance waterborne polyurethane grouting material (WPUGM) wassynthesized through prepolymerized methods. The main research and experimentalresults were divided into two parts.A series of environment-friendly WPUGM were synthesized from hydrophilicpolyether polyol (Mn=6500g/mol), tolylene diisocyanate (TDI) and diphenylmethanediisocyanate (MDI). The effect of many factors on the properties of WPUGM wasinvestigated, such as the content of remained NCO group in pre-polyurethane, diluent,catalyst and retarder, while thermal stability of the material was also determined. Theresult showed that with the increasing of the mole ratio of TDI to polyol, the density,viscosity and foaming capacity were initially decreased and then increased, whilewater absorption capability, water swelling ratio and gel time were increased in thebeginning and then decreased. With the increasing of the mole ratio of MDI to polyol,the density, viscosity, gel time and water absorption capability were decreased, whilefoaming capacity and water swelling ratio were both increased. With the content ofdiluent, the density was increase and the viscosity was decreased, while the gel timeand water absorption capability unchanged in general. When the isocyanate index R1was1.5, R2was6and the content of diluent was25%, the WPUGM had a bettercombination property: the density was1.1265g/mL, the viscosity was535cp, thewater absorption capability was117s, the gel time was49s, the foaming capacity was1,144%and water swelling ratio was190%.PU/SiO2composites was prepared by pre-polymer polymerization and in-situpolymerization with nano-SiO2as modifier respectively, while the effect of SiO2content on the properties of composites was investigated. The FT-IR was employed toconfirm the structure of composites, and the results showed that group of-OH on thesurface of nano-SiO2particles had reacted with the-NCO group from the TDI andMDI. With the dosages of the SiO2increasing, the density, viscosity, solid content andgel time of PU/SiO2were all increased. The water absorption capability, foamingcapability and water swelling ratio were all decreased. The rapidest decompositiontemperature almost had no changes, but residual yield of material were increased withthe increasing dosages of SiO2, so the compressive strength was also increased withSiO2introduced into the WPUGM, while the compressive strength of composite gotto0.12MPa when the mass ratio of SiO2was1.5%. In comparing, the PU/SiO2 composites was prepared by in-situ polymerization could get the combinationproperty, when the mass ratio of SiO2was0.5%, the viscosity, density and solidcontent of composites were960cp,1.140g/mL,78.54%; while the gel time, waterabsorption capability, foaming capability, water swelling ratio and compressionstrength were53s,113s,1003%,110%, and0.10MPa respectively.