Studies On The Syntheses, Characterization And Prorerties Of Waterborne Polyurethane Dispersion

The polyurethane dispersion, or its modified by acrylate and silicone has been designed, synthesized and token in this article, we studied on the effects of technical conditions for the stability and shape structure of polymer, probed into the film forming process of modified polyurethane dispersion and used acrylate modified polyurethane dispersion produced by testing plant to lay out waterborne based wood paint and waterborne based anticorrosive coatings. The result's as follow:I .Synthesizing polyurethane dispersion, which can deposit stably.Probed into the different factors for the effect of emulsion stability and the surface structure of film forming substance in the TDI-N330 reaction system, and token by using infrared ray and SEM. Found that the form of crystallization on the surface of film forming substance is globular, and the micro-crystal phenomena have been sharpened by the index Ri increasing of isocyanate. We has also probed into the effect of process stability by isocyanate index Ri in IPDI-N330 polyurethane reaction system. When Ri increases, the effort in the molecular will increase, and molecular in the emulsion will crimple in group, the distribution of molecular weight in emulsion will widen and distribution degree increase.II .Using the capping graft technology of preformed polymer to form acrylate which has goodstable deposition and water-resistanceAcrylate-modified polyether polyurethane aqueous dispersion and acrylate organosiloxane compound modified polyurethane aqueous dispersion. Azobisisobutyronitrile of oil initiator initiates and first prepolymers for a small amount and then in minim amount adds initiate extender three steps adding methods, which can increase the conversion of unsaturated monomer reaction and the filming water tolerance of emulsions. The acrylate modification and acrylate organosiloxane compound modification can obviously decrease the degree of micro crystal in the molecular of polyurethane. Both copolymer and the conditions of emulsification process can affect the shape structure of grain in the emulsion to apart with the micro-phase of soft and hard segment. Acrylate modification not only reserves the build of polyurethane but also has good gloss. The adding of silicone makes against the increase of gloss degree of film forming substance.III.This article uses the technology of interpenetrating networks to synthesize polyacrylate modified polyurethane aqueous and polyacrylate organsiloxane compound modified polyurethane aqueous dispersion which has good hardness and toughness. The research results indicates thatwhen Ri is less than the adhibiting of silicone, it can increase the water resistance after emulsion film forming. The stability is better using 1,4-butanediol as chain extender than using ethylene chain extender system, and the water resistance after film forming is well. In some extension, the decreasing of initiator and the increasing of glass transition temperature of polyacrylate is propitious to increase the conversion of unsaturated monomer and at the same time, the gloss, drying, hardness and water resistance of film forming substance reform. Adding a small quantity of three functional group of polyvalent (TMP) can improve the water resistance and decoration of copolymer emulsion after film forming. The structure form of interpenetrating networks has a greater destroy degree to the micro crystal of polyurethane film forming substance than the effect of the prepolymer capping graft copolymer.IV, This article studies on the heat stability of acrylate modified polyurethane dispersion, researches the changes of the structure of acrylate modified polyurethane dispersion afterheating, and analyses by the heat analysis, infrared ray and heat analysis, and mass spectrometery. The result indicates that acrylic modified polyether polyurethane after heating, bonds of carbamate and allophanate in molecular cleavages underlying and then releases water and carbon dioxide.V .This article studies on the light stability of acrylate modified polyureth...