Polydispersity and functional group distribution of dispersant polymer: Adsorption properties and magnetic paint dispersion

The quantitative analysis examining the functional group distribution of a dispersant polymer for magnetic paints is conducted by statistical estimati on and adsorption experiments. The dispersant polymer contains averagely on e or two functional groups on the chain, and has generally large polydisper sity. By the calculation based on the random distribution of the functional group and the molecular weight, a typical design of the dispersant polymer is found to contain a significant amount of nonfunctionalized chains and h ighly functionalized ones. In adsorption experiments, the adsorbed amount o f the polymer mass and the functional group are separately measured to dete rmine the functional group distribution. The distribution is also evaluated by a sequential adsorption experiment, in which the chains are fractionate d by the adsorption strength. Obtained experimental results agree with the calculated results. A practical method for increasing the effective chains in the paint is to make use of a preferential adsorption of the functionali zed chain. (C) 2001 Academic Press.