Compound of Formula (1); wherein: Zw is an organic radical comprising w amino groups, in which w is a number and 5≦w≦3,000; A and B are independently oxy-C1-C20-alkylene carbonyl groups or oxy-C2-C20-alkenylene carbonyl groups derived from hydroxy carboxylic acids or lactones; T is hydrogen or R—CO—, where R is a C1-C50 hydrocarbyl group; Y is a C3-C4-alkylene radical linked to an amino group of Zw; Y′ is an ionic salt link between an amino group of Zw and the terminal carbonyl of (A)r-(B)p-T; r and p are independently numbers between 0 and 50 and r+p>2; s, m and v are numbers; 0.99w≦s+m≦2w; and 0.3w≦s+v≦2w are suitable as dispersants and milling aids.