Hexamethylene diisocyanate

Hexamethylene diisocyanate (HDI) is an aliphatic diisocyanate monomer belonging to the class of isocyanates. It is primarily used in the production of polyurethanes. The isocyanate functional groups in hexamethylene diisocyanate react readily with polyols to form polyurethane polymers. Polyurethanes derived from HDI are commonly used in various products, including coatings, adhesives, sealants, elastomers, foams, thin-film transistors, flexible or rigid plastics, biomedical applications, electronics and aerospace industries. It is also used to produce oligomers and prepolymers that when combined with a polyol produce light-stable polyurethane.

Hexamethylene diisocyanate (HDI) is used as:

• A crosslinker to crosslink the polyurethane chains in the triblock copolymer gate dielectric, which is then deposited on the substrate to fabricate low-voltage organic thin-film transistors.
• A precursor in the preparation of electroactive shape memory polyurethane/graphene nanocomposites. These materials are usually used as actuators, sensors, artificial muscles, smart devices, and microswitches.
• A crosslinker in conjunction with Pluronic F127, a nonionic surfactant, to synthesize a poly(lactic acid) (PLA)-based hydrogel for biomedical applications.

Highly reactive 1,6-hexamethylene diisocyanate (HMDI) was used to synthesize lactic acid polymers from oligomers by the addition of 2,2′-bis(2-oxazoline) (BOX) as chain extenders. Self-healing ability was rendered to polyurethane elastomer by synthesizing alkoxyamine-based diol and reacting it with tri-functional homopolymer of HMDI and polyethylene glycol (PEG). Plastic optical fiber (POF) was prepared by the bulk homopolymerization of HMDI catalyzed by Tin(II)-2 ethylhexanoate (SnOct).