Dimethylthiotoluenediamine
A slower aromatic diamine extender that gives polyurea and cast elastomers more flow time than DETDA.
Dimethylthiotoluenediamine (DMTDA) is an aromatic diamine whose ring carries two methylthio (–SCH₃) groups beside the amines. It is a liquid isomer mixture sold as Ethacure® 300 and equivalents, with a molecular weight of about 214 g/mol.
DMTDA is used as a chain extender in polyurea and in cast polyurethane elastomers, often as a liquid alternative to MOCA in cast systems. In spray polyurea it is blended with or substituted for DETDA to extend gel time, improving leveling, substrate wet-out and adhesion.
The electron-withdrawing, bulky methylthio groups slow the amines’ reaction with isocyanate compared with DETDA. Its amine equivalent weight per NH₂ is about 107. The sulfur groups can give a characteristic odor and some color.
Handle as a hazardous aromatic amine: gloves, eye protection and ventilation, and follow the SDS for specific health warnings.
Slower gel lets the material flow and wet the substrate before setting, which can improve adhesion and surface appearance, especially on rough or porous surfaces.
Yes. It is common as a chain extender for cast polyurethane elastomers cured with TDI or MDI prepolymers.
