Preparation Of High Solid Content And Low Viscosity Polyacrylate Emulsion By Double Polymerisable Emulsifiers

With ammonium sulfate allyloxy nonylphenoxy poly(ethyleneoxy)(10) ether (DNS-86) and allyloxy poly(ethyleneoxy)(44) ether (F-6) as compound polymerizable emulsifiers, ammonium persulfate(APS) as initiator, methyl methacrylate(MMA) and butyl acrylate(BA)as monomers, so a seed emulsion with20%solid content was synthctized by semibatch emulsion copolymerization. The influences of the compound polymerizable emulsifier ratio, the reaction temperature (T), the concentration of initiator ([Ⅰ]) and emulsifier ([E]) on the polymerization kinetics for semi-continuous emulsion polymerization were studied, and the effect of compound polymerizable emulsifier ratio on polymerization rate and average particle size were analyzed especially. The experimental results show that the optimum ratio of compound polymerizable emulsifier was about F-6/DNS-86=1/2, the relation of apparent polymerization rate (Rp) with [E] and [Ⅰ] was Rp∝[E]0.6082[Ⅰ]0.5805, the apparent activation energy53.7317kJ/mol (343.15K-363.15K) was obtained.With the seed emulsion as medium, A series of62%high solid content and bi-particle size distribution acrylate latexes were successfully prepared via re-nucleation emulsion polymerization, using F-6and DNS-86and octylphenol polyoxyethylene(10) ether (OP-10) and sodium dodecyl sulfateas (SDS) as the emulsifiers respectively, feeding pre-emulsion (compound emulsifier and monomer mixture), initiator and the buffer at the same time. The effects of the factors such as the emulsifiers type, dosage of emulsifiers, the compound way and the ratio of emulsifier, reaction temperature, monomer component on stability of the polymerization, the rheological properties of the latex, the stability of latex and latex film were stuied mainly. Using F-6and DNS-86as compound polymerisable emulsifiers was an effective method for preparing high solid content(HSC) and low viscosity(LV) latex during re-nucleation section. The results showed that the dosage of the compound polymerisable emulsifiers was2%of monomer total mass and m(F-6)/m(DNS-86) was1/2, the dosage of the APS was0.3%of monomer total mass, the content of BA and AA in monomer was about60wt%and3wt%respectively, reaction temperature was80±5℃, the emulsion a bi-particle size distribution, including large latex particle size was about449nm, the small latex particle size was about70nm was obtained. The solid content of the latex was about62.24%and the gel rate was less than0.5%. The viscosity of corresponding latex was able to keep a lower value, below300mPa-s when shear rate was30r/min. In addition, the stability of the polymerization, latex and latex film were stronger respectively.