Cross‐linking of Hydroxyl‐terminated Polyols with Triethyleneglycol Diglycidyl Ether: An Alternative to Toxic Isocyanates

Isocyanates are highly reactive and toxic substances with severe health effects. Certain diisocyanates are restricted under REACH – The European Regulation on Registration, Evaluation, Authorisation and Restriction of Chemicals. Triethyleneglycol diglycidyl ether (TEGDGE) was used as an alternative to toxic isocyanates for the cross‐linking of hydroxyl‐terminated pre‐polymers at 70 °C. The effect of three curing accelerators was determined while following the reaction kinetics by 1H‐NMR spectroscopy and differential scanning calorimetry (DSC). Polybutadiene (Poly BD R45HT‐LO) and acrylic ester (HyTemp 4454) successfully cross‐linked in 7–10 days to produce thermally stable networks with low glass transition temperatures, as observed by DSC. Pre‐aging the polybutadiene resin promoted cross‐linking with TEGDGE. Four energetic compositions were then prepared using cyclotrimethylenetrinitramine (RDX) and pentaerythritoltetranitrate (PETN) as fillers, and polybutadiene (Poly BD R45HT‐LO) and acrylic ester (HyTemp 4454) as binders. Both binders successfully cross‐linked with TEGDGE in the presence of RDX and PETN, but only PETN was found to be chemically compatible with the cross‐linked polymers. These results show that TEGDGE is suitable as a replacement for toxic isocyanates for the cross‐linking of hydroxyl‐terminated polyols.