Preparation of Temperature-Sensitive Polyurethanes Based on Modified Castor Oil

A series of temperature-sensitive polyurethanes (TSPUs) with polytetrahydrofuran glycol (PTMG), poly(ethylene glycol) (PEG) and maleic anhydride modified castor oil (MCO) as soft segments were prepared in this paper. The morphology of the temperature-sensitive polyurethane films was characterised by SEM, DSC and WAXD. SEM studies were also carried out to investigate the surface structure of coated and uncoated fabrics. The water vapour permeability of the coated and uncoated fabrics were measured as well. The results showed that a nonporous TSPU layer was formed on the coated fabric surface. The tailor-made TSPUs had one to three soft segment crystal melting point temperatures, with the the lower peak temperature T-pm1 belonging to the soft segment PTMG and the higher peak temperature T-pm2 to the hydropilic soft segment PEG2000. The water vapour permeability of TSPUs coated fabrics increased with an increase in PEG2000 concentration and PEG molecular weight, but decreased with an increase in the hard segment content, and triggered around the soft segment crystal melting point temperature of TSPUs.