Preparation And Application In Paper Processing Of Non-ionic Waterborne Polyurethane

Waterborne polyurethane is one class of novel paper-making chemical which takes water as the dispersion medium.It is non-flammable,non-toxic,environmental friendly and etc.In addition,waterborne polyurethane has some advantages such as excellent film-forming performance,as well as good sizing effect,adhesion and printability.Therefore,it has been widely used in paper processing field and can improve paper properties effectively,which attracts more and more people's attention in recent years.Non-ionic waterborne polyurethane(WPU)emulsions were synthesized by self-emulsification in the research.The discussion about the effects of the way of adding water,temperature of emulsification,the isocyanate index(R),mass percent of polyethylene glycol(PEG)and mass percentage of ethylene diamine(EDA)for WPU emulsions and film properties were performed.Meanwhile,the composite emulsions were prepared by blending WPU and carboxylated styrene-butadiene latex(XSBRL),the effect investigation of the blending ratio and WPU with different PEG content for XSBRL-WPU composite emulsions and film properties were also carried out.Finally,XSBRL-WPU composite emulsions were applied in paper coating.The properties of WPU and XSBRL-WPU composite emulsions on the stability,particle size and viscosity were measured by DLS,senior rotary rheometer and etc.Besides,the properties of WPU film and XSBRL-WPU composite film were studied with XPS,ATR-FTIR,DSC,AFM,contact angle measuring instrument and TG,especially the surface properties of film.The conclusions indicate that the stability of non-ionic waterborne polyurethane(WPU)emulsions synthesized by self-emulsification are good,with its acid alkali resistance and electrolyte resistance and etc.the hydrogen bonds between hard and hard segments weaken with the increase of PEG content for WPU system,which makes the micro-phase separation degree between hard and soft segments decrease.Meanwhile,the surface roughness decreases with the increase of methyl groups content on the WPU film surface,which makes the surface energy decrease and the water contact angle increase.While for XSBRL-WPU composite system,WPU can improve the surface properties of the composite film,the compatibility between WPU and XSBRL becomes worse with the increase of WPU mass percentage,and the surface energy on the composite film at first increases and then remains basically unchanged,and the water contact angle at first decreases then remains basically unchanged.The compatibility between WPU and XSBRL becomes worse with the increase of PEG content in the WPU,besides,the surface energy on the composite film increases,and the water contact angle decreases.Coating experiments show that the application of XSBRL-WPU composite emulsions in paper coating can increase water-resistance of paper.