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Synthesis of polystyrene / acrolein latexes and their surface characterization

University of British Columbia

A semi-continuous synthesis of polystyrene/acrolein latex was carried out. The optimum addition time of acrolein monomer was determined to be 10 hours after addition of the initiator, giving a monodisperse polystyrene latex with aldehyde on the surface. A DNPH assay was used to assay the aldehyde group in the latex suspension; it was specifically a surface assay. It successfully detected aldehydes at concentrations above 1 x 10⁻⁶ mol/g but was limited at high surface concentrations of aldehyde probably due to the steric hindrance. Quantitative agreement with respect to surface concentration of aldehyde groups was obtained using freshly solubilized NaBT 4 reduction in a radiochemical assay. NMR was used to assay aldehydes present in dissolved latex and the same result as for the DNPH assay was obtained. NMR provided information on the environment of the surface aldehydes, the chemical shift showing the possible presence of polyacrolein chains on the latex with the seeded reaction. This was an important observation as the polyacrolein blocks are not favorable for the grafting reactions to be carried out later in this project. XPS provided strong evidence that aldehyde functions were present on the latex surface, were reactive with DNPH and were reduced by NaBH₄. The XPS spectra obtained were those expected based on the surface chemistry anticipated and no unexpected groups were detected.

Thesis/Dissertation

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2009-02-26

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http://hdl.handle.net/2429/5208

Chemistry

University of British Columbia

UBCV

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