| PU materials are used widely because of its high strength, high solvent resistance, excellent wear resistance, wide range of hardness and flexible design of formula. Both ether group in polyether polyols of polyether PU soft segments and urethane carboyl(-C=O) in hard segments can form hydrogen bonds with amino(-NH2) in hard segments, which influence the micro-phase separation of PU systems. This is the micro-factor that why PU has excellent mechnical performance and better macro performance.Glycine-semi-organic crystal is a kind of special material with pyroelectric effect. There are a huge number of amino(-NH2) on the surface of these materials which can be used as hydrogen supplying group and formed hydrogen bonds with ether group or carboyl(-C=O) in PU systems, thus affect the microstructure and macro-properties. Inorganic nanoparticles usually has unique structure and larger surface area, which lead to physical or chemical combination with chain segments of PU. On the one hand, this impact the microstructure and micro-sepration of PU, on the other hand, can form composite materials.PU composite materials were prepared by pre-polymerization using polyteramethylene ether glycol(PTMG), 2,4-toluene diisocyanate(TDI-100) and 3,5-dimethylthiotoluenediamine(DMTDA, E-300) as raw materials, using 13X-molecuar sieve, aerosil and allyl alcohol polyoxyethylene ether composited with glycine-calcium bromide semi-organic crystal(referred to as composite particles) respectively as modifer. The macro-performance and microstructure of PU were characterized by mechanical properties test, differdential scanning calorimetry(DSC), dynamic mechanical analyzer(DMA), fourier transform infrared(FTIR), thermogravimetric analysis(TGA) and atomic force microscope scanning(AFM).The results demonstrated that the mechnical porperties of PU composite materials changed greatly. The tear-resistance strength and tensile strength improved largely compared with pure PU and presented certain regularity with the increase of adding composite particles. FTIR results suggests that characteristic peak of carbonyl region and amidogen region occurred red shift and an increasing number of carbonyl and amino group generated hydrogen bonding effects in PU systems, which enhanced the hydrogen bonding degree of hard segments in PU systems. TGA analysis showed that composite particles improved the heat resistance of PU. DMA results verified that composite particles increased storage modulus significantly and was also higher than pure PU while the temperature was more than 60 ℃, which declared that hard chain segment crystallinity were increased and the heat resistance performance of composite materials were better. The reduce of loss modulus and.glass transition temperature(Tg) incidated that the endogenous heat of PU composite materials reduced accordingly, which lead to the micro-phase sepregation was better.The DSC results indicated that the area and temperature of crystal melting peak in hard segment raised, which stated that the crystallization of hard segment increased and the glass transition temperature(Tg) of PU were reduced after adding composite particles. Therefore, composite particles perfected the micro-phase sepregation of PU. AFM pahse diagram and three dimentional stereogram exhibited the microstructure of PU intuitively. The figure showed that crystal patticles of hard segment in PU composite materials increased obviously, which illustrateed that the micro-phase sepregation of PU were improved dramaticlly by composite particles. |
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