Abstract:

The effect of the mass ratio of methyl methacrylate (MMA) to butyl acrylate (BA) , namely F , on the nucleation mechanism and the particle size distribution in semi-continuous emulsion polymerization was investigated, with MMA and BA as the monomers , potassium persulfate (KPS) as the initiator and sodium dodecyl benzene sulfonate (DBS) as the emulsifier. The results show that (1) the nucleation mechanism of the system is both homogeneous nucleation and micelle nucleation when F is more than 0. 75 , while remaining mainly micelle nucleation when F is less than 0. 5; (2) the particle size of the resulted latex in the homo-polymerization system is smaller than that in the co-polymerization system; and (3) the abrupt transition disciplinarians of the conversion rate , the color and the particle size are correlative to each other at the end of the nucleation process.

Key words: semi-continuous emulsion polymerization, nucleation mechanism, particle size distribution, monomerratio