Control of Crosslinking
In thermoplastic polyurethanes, very little or no crosslinking
Accomplished by control of curative (glycol)
Thermosetting polyurethanes can be made by several techniques:
- Use of less than the stoichiometrically required amount of curative will cause allophanate or biuret formation
- Due to urethane or urea linkages reacting with remaining isocyanates