Synthesis Of Large Particle ASA Latex Via Agglomerating Method

The agglomerating method is an effective method which could steadily turnsmall latexes into larger particles. Poly(n-butyl acrylate-co-acrylic acid)[P（BA-co-AA）] were synthesised via multistep emulsion polymerization with butylacrylate (BA) and acrylic acid (AA) as raw materials and the compound of dodecylsulfate and Triton X-100as the emulsifier. Then, as-prepared P(BA-co-AA)latexes as agglomerant were used to agglomerate the PBA latexes, and the effect ofvarious ratios of BA and AA, dosages of P(BA-co-AA) latexes, the time, thetemperature and pH values during the process of agglomeration on theperformance of PBA latexes were researched. Finally, the large particlePoly(acrylate-styrene–acrylonitrile)(ASA) latexes were obtained and themechanical properties of the ASA resin was tested.The main results as follows:Firstly, the large particle sizes of PBA latexes were prepared viaagglomerating method and the monomer ratios of the agglomerant, could greatlyaffect the result. While the AA mass content was between15%~20%in theagglomerant, the particle sizes of PBA latexes could enlarge to more than fourtimes, which demonstrated excellent agglomeration performance.Secondly, the amount of agglomerant latexes had a great influence on theperformance of PBA latexes. The experimental results indicated that theagglomeration effect of the system was not obvious when the amounts ofagglomerant latexes were lower than3%wt, and the process would becomeinstable to separate out the colloid when the amount of agglomerant latexesreached more than30%wt. But when the amount was varied from5%to20%wt,the particle size of PBA latexes were enlarged more than4times, simultaneously,the surface potential of PBA latexes decreased to some extent after agglomeration.Thirdly, the as-prepared agglomerant latexes had a significant effect on theparticle sizes of ASA latexes. The PBA particle sizes could achieve278nm and theASA particle sizes would reach304nm with agglomerating method. At last, the amount of agglomerant latexes had a great effect on theperformance of ASA resin. The mechanical properties of the modified ASA resinincreased firstly, and then gradually decreased with the increasing of agglomerant.The materials achieved its maximum tensile strength when the mass fraction ofagglomerant latex in ASA resin reached nearly15%wt, and maximum notchedimpact strength was obtained when the ratio of agglomerant latex reached about20%wt.