Study Of Miniemulsion Polymerization Of PUA-LIPN

Latex interpenetrating polymer networks(LIPNs) are an important kind of multifunctional novel polymer material with outstanding performance , in which the interpentrating structure of different polymers and the microphase seperation of same polymers coexist. The aqueous preparation method have accomplished the environmentally friendly synthesis and application. Polyurethane and polyacrylate have the most broad application in water-borne coatings, and there is much complementation between them. As a result, PUA hybrid emulsion is the hot issue of recent emulsion research.According to the disadvantage of the conventional two-step polymerization, the one-step in-situ miniemulsion polymerization is at first introduced to obtain Polyurethane/Poly(fluorinated) acrylate latex interpenetrating polymer networks (PUA -LIPN). The stability of isophorone disocyanate(IPDI) and the affecting factors of in-situ miniemulsion polymerization have been studied to carry out the simutaneous or two-step procesure of polyaddition and radical polymerization.The stability of water-sensitive monomer IPDI has been studied in IPDI-H20 system. NCO% is measured by toluene-dibutylamine with the improvement of agitation and demulsion, with the relative deviation of 0.30%. IPDI has remained stable in the miniemulsion preparation and storage. It has been found that catalyst and the increasing temperature accelerate the hydrohlysis of IPDI, because the inferior urea passivation is invalidated.The polyaddition of isophorone disocyanate(IPDI) with diol has been performed in miniemulsion to obtain PUA-LEPN. The influence of several factors, such as temperature, surfactant, catalyst, and BMA, on the selectivity of polyaddtion/hydrolysis and the molecular weight has been studied in detail. It has been found that the use of a solvent of the polyaddition medium, or an off-stoichiometric ratio of the isocyanate and the diol component permits to considerably retard the hydrolysis reaction and increase the molecular weight of thepolymer. It is also shown that two-step interpanetrating procedure prefer to the polyaddtion of IPDI and diol. The hybrid polymer nanoparticles based on poly(butyl acrylate) /polyurethane (PBA/PU) can been synthesized using a one-pot procedure. The addtion of fluorinated acrylate is in favor of the stability of monomer miniemulsion and decrease the volatile organic compounds(VOC). The aqueous preparation method have accomplished the environmentally friendly synthesis and application of PUA hybrid emulsion.