Carboxylic acid groups, latexes prepared with

It has been proved that incorporation of carboxylic acid groups in the polymeric chain has a significant effect on colloidal properties of latex, processability, and end-use property. Carboxylated styrene-butadiene latexes (XSBR) are prepared via batch emulsion copolymerization with different amounts of acrylic acid in the absence of emulsifier. They are among the most important polymeric colloids, and can be used as binder in paper coatings, carpet backing, paints, and nonwoven. There are several studies on the preparation and properties of XSBR latexes. 

In reaction systems in which carboxylation is effected by the use of the half-esters of unsaturated dicarboxylic acids and mono-hydric alcohols, acid-catalysed hydrolysis of the half-ester can be a factor which complicates the distribution of carboxylic-acid groups in the final latex (15) the shorter is the alkyl chain length of the alcohol from which the ester was prepared, the greater is the tendency to hydrolysis. The presence of interaction products of carboxylic acids and one or more of the main monomers can be a further complicating factor an example is the foimation of surface-active products by Biels-Alder reaction between dienes and unsaturated acids thus butadiene can react with maleic acid to form 1,2,3 6-tetrahydrophthalic acid (15) ... 

Many investigators have studied polymer surfaces for years [74,75] and have been successful in determining combinations of two or more valence states [76,77] by the mathematical process of deconvoluting the peak assignments [78]. It was only recently that latexes were examined by ESCA. Davies et al. [79] prepared a series of homopolymers of poly(methyl methacrylate) (PMMA) and poly(butyl methacrylate) (PBMA), and also poly[(methyl methacrylate)-co-(butyl methacrylate)] (PMMA-PBMA), by surfactant-free emulsion polymerization. It was found that the surface of the latex film was rich in PMMA, which may possibly be explained by the reactivity ratios for the MMA/BMA system (ri = 0.52 and rj = 2.11) [80], Recently, Arora et al. carried out angle-dependent ESCA studies on a series of films prepared from core-shell ionomeric latexes (with a polystyrene core and a styrene/n-butyl acrylate/ methacrylic acid copolymer shell) to determine the distribution of carboxyl groups in the films [81,82]. 

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