Preparation, Structure And Properties Of Polyurethane-Imide (PUI) Elastomer

In order to improve the high-temperature performances of polyurethane (PU) elastomer and enlarge its application fields, modification of PU by introducing imide-heterocycle and preparation of polyurethane-imide (PUI) elastomer composites have been becoming one of the key points in the field. In this dissertation, it consists of three main parts about the synthesis of polyurethane-imide (PUI) elastomer composites as follows: synthesis of polyurethane modified bismaleiimide (UBMI), characterization of UBMI-PTHF and UBMI-HTBN, preparation and characterization of polyurethane-imide (PUI) elastomer composites.Synthesis of polyurethane modified bismaleiimide (UBMI). The reaction possibility of maleic anhydride(MA) with NCO group terminated polyurethane prepolymer (PUP) , which occurs in bulk or solvent with very low boiling point and low polarity, were discussed. It was found that the reaction can be carried out in ketones, especially in acetone. With polytetramethylene ether glycols (PTHF) and polybutadiene-acrylonitrile copolymer glycol (HTBN) as the raw materials, two kinds of UBMI resins(UBMI-PTHF and UBMI-HTBN ) were synthesized in presence of acetone.Characterization of UBMI-PTHF and UBMI-HTBN. Copolymerization of double bond in UBMI and effects on the thermal stability of UBMI were discussed by thermogravimetric (TG) analysis and differential scanning calorimetry (DSC). Based on this, the processibility of UBMI-PTHF and UBMI-HTBN was discussed for the preparation of polyurethane-imide (PUI) elastomer composites. It was found that the thermal stability of UBMI-HTBN is better than that of UBMI-PTHF while the processibility of UBMI-PTHF is better than that of UBMI-HTBN.Preparation and characterization of polyurethane-imide (PUI) elastomer composites. In order to improve the processibility of UBMI, PUP was mixed with UBMI. The preparation technology of polyurethane-imide (PUI) elastomer composites from the prepolymer mixture of PUP and UBMI-PTHF by bulk polymerization was discussed and assured. Effects of the amount of DMTDA, the addition of 2,5-dimethyl-2,5-bis(tert-butylperoxy)-hexane(B25), the type of diisocyanate methyltoluene(TDI) and the amount of UBMI-PTHF on the properties of polyurethane-imide (PUI) elastomer were investigated. The properties of polyurethane-imide (PUI) elastomer were discussed by thermogravimetric (TG) analysis, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), stress-strain machine and some other testing methods. It was found that compared with pure PU elastomer, PUI elastomer composites have better high-temperature durability, high-temperature dynamic mechanical properties and solvent durability , but lower mechanical properties at ambient temperature.