Preparation And Properties Of Phosphorus Flame Retardant Hyperbranched Waterborne Polyurethane

Water-based polyurethane is a polyurethane system that uses water as a dispersant.It not only has the good properties of the traditional solvent based polyurethane,but also has the advantages of the general solvent based polyurethane,which has little odor,non-toxic and clean.It is in line with the concept of modern environmental protection.The hyperbranched waterborne polyurethane is class of highly branched macromolecules with a three-dimensional sphere and a cavity inside.The structure gives the unique physical and chemical properties of the hyperbranched waterborne polyurethane,such as a large number of functional groups at the end of the branched chain,which is suitable for various modifications.These excellent properties enable hyperbranched waterborne polyurethane to be applied to high technology fields such as UV curable coatings,phase change materials,synthetic leather and biological materials.Therefore,the study of hyperbranched waterborne polyurethane has attracted more and more attention.In this paper,a hyperbranched waterborne polyurethane was synthesized.With 2,4-Toluene Diisocyanate(TDI),Polypropylene Glycol(PPG-1000),Diethanolamine(DEOA)and Dimethylol Propionic Acid(DMPA)as the basic raw materials,the hyperbranched waterborne polyurethane was prepared according to the A2+CB2 synthesis route.By optimizing the formula,it is determined that when the R value(-NCO/-OH)is 1.4,the mass fraction of DMPA and the mass fraction of DEOA are both 5%,the properties of the emulsion are excellent and the film forming is good.The product was characterized by IR and 13C NMR.It was confirmed that the target product was hyperbranched waterborne polyurethane.On the basis of the above experiment,the flame retardant chemical modification of hyperbranched waterborne polyurethane was studied?Hyperbranched waterborne polyurethane with FR6 content of 5%,10%,15%and 20%was sequentially produced by using organophosphorus diols(flame retardant FR6).The samples were tested that the flame retardants were successfully introduced into the molecular chain,and the properties of the emulsion were related to the content of FR6.With the increase of FR6 content,the emulsion color gradually turns yellow from milky white,and its stability,film formation,freeze-thaw cycle resistance,and toughness gradually deteriorate;the viscosity of the emulsion first decreases and then increases;.but the range of PH is increasing.The oxygen index of FR6 samples containing 15%and 20%was 28.4%and 33.3%respectively,and reached the level of non combustible.The combustion of flame-retardant modified hyperbranched waterborne polyurethane was investigated by infrared analysis,thermal analysis and SEM analysis.The maximum decomposition temperature of the unmodified hyperbranched waterborne polyurethane film was 400?,the decomposition temperature was 500 ?,the amount of residual carbon was 4%,the carbon layer fragments after decomposition were more;The maximum decomposition temperature of the modified film(15%FR6)was 360?,and the final decomposition temperature was 420?.The decomposed carbon layer was complete,continuous and smooth,and the flame retardant effect was obvious.