Study On Modification, Morphology And Properties Of Polyether Polyurethane(Urea)

Polyurethanes (PU) are becoming more and more important as engineering materials, due to their many excellent properties such as high abrasion resistance, chemical resistance and high flexibility. However, it's well known that conventional polyurethanes exhibit poor thermal stability, which limits their more application in many fields.An effective way to improve the thermal and mechanical properties of polyurethane is a chemical modification by introducing heteroaromatic groups into polyurethane backbones. In this work, polyurethanes have been modified in view of hard and soft segment respectively. Three novel diamines or diols have been synthesized and were used as the chain-extender to prepare polyurethane(urea) elastomers. In addition, polyurethane was modified by incorporating polydimethylsiloxane into its soft segments in the last sector. The main contents were listed below:1. Polyurethane modified by imide-containing diolsA series of new glycols containing imide groups, sulphonyl bisimide glycols (SBIGs), were prepared from primary aromatic diamine,trimellitic anhydride and excess low molecular glycols. The structures of SBIGs were confirmed through Fourier transform infrared spectra (FTIR) and elements analysis (EA) etc. Then these SBIGs were used as chain extenders to prepare a class of thermoplastic poly(imide-urethane)s (PIUs), which have been introduced imide rings into the backbones. The modified elastomers were characterized by means of FTIR, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanic thermal analysis (DMTA), stress-strain measurement and wide angle...