| Polyurethane elastomer (PU) is widely used for its excellent properties, andits superior performance was direct related to the hydrogen bonds between softand hard segment of its composition structure. The presence of hydrogen bondspromote the orientation of hard segments, thus contribute to the micro-phaseseparation. Meanwhile，it played a role as the physical crosslinking. Thehydrogen supplying group (-NH) of polyether polyurethane elastome systemcould formed hydrogen bond with carbonyl (=O) of hard segments, and formedhydrogen bond with ether group (-O-) of soft segments. Semi-organic crystalwas a kind of crystalline material which was synthesized with inorganic saltsand organics under certain conditions. The paper synthesized seriesglycine-inorganic semi-organic crystals, which used as hydrogen supplyinggroup that had interaction with carbonyl and ether groups of polyetherpolyurethane system for its special crystal surface, and then affected themacroscopic properties and the microstructure of the system.At the same time, the interaction of soft segment with hard segment in thepolyurethane structure affected its strength, increased the number of ether bond in polyether polyurethane system must affect the degree of hydrogen bonding ofthe ether bond, and affected the macro-performance of system.Modified polyether polyurethane elastomers were prepared usingpolytetramethylene (PTMG), diisocyanate (TDI-100),3,5-dimethylhiotol-uenediamine (DMTDA, E-300) as materials, semi-organic crystals andTPEG-2400as modifier by prepolymer method.The modified PUs werecharacterized by mechanical properties analysis, fourier transform infrared(FTIR), differential scanning calorimetry (DSC), thermalgravi-metric analysis(TGA) and dynamic mechanical analysis (DMA).The results showed that:1) Polyether polyurethane/semi-organic crystal composites had superiortear strength and tensile strength compared with blank samples, and with theincrease of average chain extension coefficient was enhanced; the elongation atbreak reduced at prime tense and increased with the increase of semi-organiccrystals afterwards. FTIR results suggested that adding semi-organic crystalshifted the characteristic absorption peak of carbonyl to the low band, enhancedthe degree of hydrogen bonding of carbonyl and ether groups in composites.TGA results showed that the semi-organic crystals can’t improve the heatresistance of polyether polyurethane. Synthesized the glass transitiontemperature (Tg) measured by DSC and the Tg based on loss modulus (E′′)measured by DMA, discovered that the glass transition temperature (Tg) wasreduced which means semi-organic crystals had effect on micro-phase separation of polyether polyurethane. Besides, DMA results also showed thatsemi-organic crystal of the storage modulus of polyether polyurethane/GBDcomposites increased, while the loss modulus reduced slightly.2) The tear strength and tensile strength of low hard segment content ofpolyether polyurethane/semi organic crystal composites were amelioratedapparently compared to blank samples. DMA results showed that the influenceof GCB and GBD for micro-phase separation low hard segment content ofpolyether polyurethane was not obvious.3) The tear resistance strength of polyurethane improved greatly with asmall amount of TPEG, while the elongation at break and tensile strength werereduced with the increase of the content of TPEG. TGA results showed thatTPEG decreased the heat resistant properties of polyurethane slightly. DSCresults showed that adding TPEG reduced the glass transition temperature ofpolyurethane. DMA results indicated that the introduction of TPEG inpolyurethane could enhance the storage modulus and loss modulus, and themicro-phase separation was improved for the decrease of the glass transitiontemperature (obtained from E″-T curve). |
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