Chemically-modified latices: 1. Prevulcanized latices

Abstract

The subject of this chapter and the next is chemically-modified latices. These are defined as latices which contain polymer particles which have been subjected to some form of chemical modification after the latex has been formed as such. Thus, for example, functionalized synthetic latices which have been produced in the usual manner (i.e., as described in section 10.3 of Chapter 10) are not usually regarded as being chemically-modified, notwithstanding that the dispersed polymers have been chemically modified relative to the polymers dispersed in equivalent non-functionalized latices. However, a functionalized latex would be regarded as having been chemically modified if the functional groups had been introduced into the dispersed polymer after the latex had been prepared as such. A hypothetical example of a preparative procedure of this latter type is one in which the first step is the production by emulsion polymerization of a functionalized latex which contains a polymer having pendant functional groups capable of being hydrolysed to carboxylic-acid groups; then, in a second step carried out after the emulsion polymerization is complete, some or all of those functional groups are hydrolysed to carboxylic-acid groups.