The effect of β-cyclodextrin on formation of poly (styrene-butyl acrylate) latexes and their film performance

• β-CD was used to promote the formation of P(St-BA)/β-CD nanoparticle latexes.
• The films in the presence of β-CD present better water resistance and higher tensile strength.
• P (St-BA)/β-CD latexes have a dense structure with a smoother surface.

P(St-BA)/β-CD nanoparticle latexes (nanolatexes) were prepared via emulsion polymerization of styrene (St) and butyl acrylate (BA) in the presence of β-cyclodextrin (β-CD) using a small amount of sodium dodecyl sulfate (SDS) below its critical micelle concentration. The average particle sizes of the nanolatexes can be well controlled from 85 to 185 nm by varying the content of β-CD from 0.4 to 2.0 wt%. The nanolatexes exhibit a highest monomer conversion and optimal stability upon addition of 1.2 wt% of β-CD. Interestingly, unlike conventional surfactant, the addition of β-CD cannot cause observable change in surface tension of the emulsion. The films obtained from P (St-BA)/β-CD latexes have a dense structure with a smoother surface compared to the P (St-BA) latex film in the absence of β-CD. Furthermore, the films in the presence of β-CD present better water resistance and higher tensile strength, probably because β-CD is able to form inclusion complexes with both soft BA component and SDS, which can enhance the rigidity of BA and prevent SDS movement to the outer surface of the resulting films.