US EPA

6660215 

Journal Article 

Control of particle size and its distribution in soapfree emulsion copolymerization of MMA-EA-AA 

Kang, K; Kan, CY; Du, Y; Li, YZ; Liu, DS; , 

2004 

Yes 

Gaofenzi Xuebao
ISSN: 1000-3304 

SCIENCE CHINA PRESS 

BEIJING 

580-584 

WOS:000224563600021 

The control of particle size and its distribution has become more and more important both in theory and in practice in emulsion polymerization field. In this study, emulsion polymerization of methyl methacrylate (MMA), ethyl acrylate ( EA) and acrylic acid ( AA) was carried out in the absence of emulsifier, and the influences of ingredients and conditions on polymerization, latex particle size and its distribution were investigated, and latex particles with narrow size distribution as well as with carboxyl groups on their surface were synthesized. The results showed that the high monomer conversion and narrow latex particle size distribution were obtained when large amount of initiator (APS) was introduced into the polymerization system at the beginning in three-step addition process. With the increase of APS and AA,the particle size decreased and the monomer conversion increased,and a similar result was also observed with the temperature increase. It was found that NH4 HCO3 is a key material for the control of particle diameter (D-p). D-P increased with the increase of amount of NH4 HCO3, and the D-p of monodispersed P(MMA-EA-AA) latex particles can be well controlled in the range from 300 to 600 nm by adjusting the amount of NH4HCO3 used. Moreover, latexes with high monomer conversion and narrow particle size distribution can be obtained when a moderate stirring rate of 300 r/min was selected.