Styrene/acrylic acid emulsion copolymers: the effect of process variables on homogeneity

✍ Scribed by Morgan, L. W. ;Jensen, D. P.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1985
• Weight: 384 KB
• Volume: 10
• Category: Article
• ISSN: 0025-116X
• DOI: 10.1002/macp.1985.020101985107

✦ Synopsis

Attempts to use high levels of acrylic acid in emulsion copolymerizations often lead to instability because of the formation of water soluble, acid-rich copolymers in the aqueous phase. The objective of this work was to study the incorporation of acrylic acid in styrene emulsion copolymers so as to develop relatively uniform alkali soluble copolymers. Several process variables were found to markedly influence copolymer homogeneity and are discussed in this paper.

THE EFFECT OF PROCESS VARIABLES ON HOMOGENEITY I NT RODUCT ION

Acrylic acid (AA) has found much less use than methacrylic acid (MAA) in emulsion copolymers except when relatively low levels are used (e.g., 1-5 weight percent of monomers). Attempts to copolymerize high levels of AA often lead to unstable latexes. The generally assumed reason for the preference of MAA is that it partitions more favorably into the growing polymer particles. By comparison AA has m r e tendency to remain in the aqueous phase where it can form a water-soluble, acid-rich polymer (Ref.1). The water-soluble polymer can have a deleterious effect on emulsion rheology, stability, particle size and the properties of products made from the emulsion.