Study On The Synthesis And Characterization Of High-performace Of Thermoplastic Polyurethanes Through Non-isocyanate Route

In this paper,non-isocyanate thermoplastic polyurethane elastomer(NI-TPUE)with good properties was obtained by adjusting the structure of hard segment and soft segment of non-isocyanate thermoplastic polyurethane(NI-TPU).The properties and proportions of soft and hard segments are selected according to the use of elastomers.The flexibility and crystallization tendency of the soft chain segment,the rigidity and volume of the hard chain segment,the ratio of the soft chain segment to the hard chain segment,as well as the influence of the properties of various groups in the main chain on the intermolecular interaction and the physical properties of the product are considered in the selection.The specific work is as follows:1.Urea alcoholysis is the reaction of high purity urea and ethylene glycol,which is a new method for synthesis of ethylene carbonate.By adjusting the type of catalyst and optimizing the reaction conditions,the best synthetic conditions can be find.After recrystallization,the obtained solid crystal was colorless and transparent,and was characterized by IR and determined by gas chromatography.2.Poly(ethylene glycol)(PEG,Mn=1000)and poly(butylene adipate)(PBA,Mn=1000)were used as double soft segments and BHHDU as hard segment.The target product NI-TPUE,with good crystallinity was prepared and characterized.A well-crystallized target product,NI-TPUE,was prepared and characterized by transurethane polycondensation.The results of GPC showed that the polymer was formed by copolymerization rather than mechanical blending,and its Mn was between 15400-22000 g/mol.The target products were synthesized by IR and NMR spectra,and the crystalline properties of the polymer were characterized by XRD.The results of DSC showed that Tm was up to 143.7?,the initial decomposition temperature was higher than 259?.The morphology of AFM showed obvious phase separation and aggregation of chain segments to form a micro-region structure.The mechanical properties were characterized by tensile test,and the results show that the tensile strength is 44.75MPa,the elongation at break is 1142%,and the elastic recovery rate is 87%when the length is 200%.3.Due to the low polarity of polyethylene glycol(PEG),it is easy to separate microphase from hard segment.Therefore,Poly(tetramethylene glycol)(PTMG),with higher polarity,is used instead of PEG.BHHDU was used as hard segment,PTMG and PBA were used as double soft segments,appropriate amount of catalyst was added to melt transurethane polycondensation,and the target product was obtained.The difference in Mn is small,between 15800 and 21100 g/mol.The theoretical phase separation degree can be calculated by the intensity of the characteristic absorption peak in the infrared spectrum.XRD characterization showed that the polymer had good crystallinity.The melting point is between 86? and 159?,the range is wide,the initial decomposition temperature is higher than 248.8?,higher than the melting point,and it is easy to process.The AFM image showed that hard-segment aggregation will form micro-region structure with different size and density,which affects the mechanical properties.It has excellent mechanical properties.The tensile strength is between 24.5and 54.5 MPa,the elongation at break is up to 1090%,and the elastic recovery rate is more than 85%at a fixed length of 200%.Different properties of elastomers can be selected according to different uses.