Effect of dose and temperature on the physical properties of an aliphatic thermoplastic polyurethane irradiated with an electron beam

• Cross-linking predominated over scission for the e-beam irradiated aliphatic TPU.
• Both BD/EG-MDI hard segments and PTMG soft segments were affected by irradiation.
• Mechanical properties were reduced by cross-linking at amorphous phase.
• Irradiation temperature had not any significant effect.

The electron beam irradiation of a fully aliphatic thermoplastic polyetherurethane was carried out in air at doses ranging from 50 to 4000 kGy at room temperature and 100 °C and a dose rate of 5.1 kGy min−1. The effects of the irradiation on the chemical structure and the physical properties were studied. Gel was obtained already at the lower dose, increasing to almost 100% gel at the higher dose, with cross-linking predominating over chain scission. FTIR and DSC measurements proved that both, soft segment and hard segment, were affected by irradiation. Mechanical properties were adversely affected by irradiation mainly due to the cross-linking produced in the amorphous part of the material. Irradiation temperature did not have any significant effect except at the highest dose of 4000 kGy.