Desorption of emulsifiers from polystyrene latices followed by spectroscopic techniques

Abstract

The desorption of emulsifier from the particle surface of latices prepared by emulsion polymerisation has been followed by spectroscopic techniques: transmission IR, X-ray photoelectron spectroscopy (XPS) and static secondary ion mass spectrometry (SSIMS) -fast atom bombardment mass spectrometryIn IR spectra, the extra band at 1710cm-' due to carboxylic groups originating from the emulsifier is fortunately visible because it is located within a window of the polystyrene peaks.XPS is a valuable surface method of analysis (contrary to IR). Nevertheless, for the latices considered here, it is impossible to extract from the very intense carbon peak information concerning variation in the carboxyl groups, which amount to less than 1%.Another important method for surface analysis is static-SIMS, which allows detection of elements and molecular species present in the first few layers with a detection limit which is less than FAB-MS permits the detection of the parent ion of the emulsifier employed. Freeze-dried powders of latices extensively purified with mixed-bed ion-exchange resins were studied for us using FAB-MS at UMIST in Manchester (UK).A comparison is made of the results obtained with these three spectroscopic techniques.(FAB-M S).

Adsorption and Desorption of Triton X-100 in Polystyrene Particles with Different Functionality

“…[3] are similar to those shown in the previous paper (15) and are not shown here. Equation [3] has the advantage of explaining the desorption results, but due to the simplicity of the model the information that we can obtain from the equilibrium constant of the second step (k 2 ) is similar to what we extracted from the classical Langmuir isotherm. Hence we conclude that more work in this direction is needed.…”

“…[3]. The fitting procedure used consists in minimizing the statistical parameter χ 2 by using standard numerical methods (21).…”

“…Historically, because surfactant has been introduced in the synthesis of the latices obtained by emulsion polymerization, the research has been directed toward discovering how to completely remove this additive (1)(2)(3)(4)(5). Normally, the surfactants used during latex synthesis are ionic.…”

Desorption of Emulsifiers from Polystyrene Latexes Studied by Various Surface Techniques: A Comparison between XPS, ISS, and Static SIMS

“…The XPS technique was however incapable of detecting the carboxyl (COOH) and hydroxyl (COH) functionalities present in extremely small amounts compared to the C−C(H) contribution to the C 1s peak. Even on the uncleaned latexes made with carboxylated emulsifiers, it was impossible to detect the carboxyl functional group …”

“…Desorption of sodium dodecyl sulfate adsorbed on biodegradable polymer colloids has been followed by static SIMS during the purification process. With the exception of our previous work, ,, this is the only publication concerned with the application of a modern surface analysis method in order to detect the surfactant remaining adsorbed after the cleaning procedures.…”