As assessed by curing time, the relative reactivity in descending order of three commonly used aromatic amine hardeners is metaphenylenediamine (MPD), diaminodiphenylmethane (MDA), diaminodiphenyl sulphone (DDS).
MPD can be considered nearly twice as last as MDA; but it is difficult to assign relative values; since end point of curing is not a precise measurement, curing time is a somewhat arbitrary quantity.Example of the adhesive strength obtainable at different temperatures with two aromatic polyamines compared with the aliphatic polyamine, tri ethylenetetramine are shown in the figure below:
