| Due to its excellent performance and broad applicability, Polyurethane elastomer (PU) has become one of the fastest growing materials in this society. The performance of PU was closely related to the structure of soft and hard segments, at the same time the incompatibility of soft and hard segments caused micro-phase separation in the molecular structure. The better effects micro-phase separation had, the better overall performance elastomer owned. There was hydrogen in macromolecular chain of the polyurethane, on the one hand played a role in the physical crosslinking, which polyurethane elastomer materials had a high strength. On the other hand, the presence of hydrogen promoted crystalline and ordered of hard segments, and improved micro-phase separation of polyurethane elastomer.Semi-organic crystal was a kind of crystalline material which has specific crystal form and it was synthesized with organic substance and inorganic salts. The paper designed semi-organic crystals which presents amino (-NH2) or urea groups on the surface, explored whether more hydrogen bonds were generated when semi-organic crystals as hydrogen group reacted with the urethane carbonyl group of polyurethane, and then promoted the degree of aggregation of the hard segments and improved micro-phase separation to achieve the effect of improving the overall performance of the polyurethane elastomer.The paper studied polyethylene adipate (PEA), toluene diisocyanate (TDI),3,5-dimethylthiotoluenediamine (DMTDA) system and polytetramethylene ether glycol (PTMG), toluene diisocyanate (TDI),3,5-dimethylthiotoluenediamine (DMTDA) system. Four semi-organic crystals were selected:thiourea-zinc sulfate (ZTS), glycine-zinc sulfate (GZS), glycine-barium chloride (GBD), glycine-calcium bromide (GCB). The polyester and poly ether polyurethane/semi-organic crystals composites were prepared by prepolymer method. The composites were characterized by mechanical properties test, and thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), fourier transform infrared (FTIR), and dynamic mechanical analyzer (DMA) were characterized for some composites, which investigated the effect of semi-organic crystals on composites. The results demonstrated that the mechanical properties of polyester and polyether polyurethane/semi-organic crystal composites were improved compared with the blank samples, and with the increase of average chain extension coefficient was enhanced. With the increase of semi-organic crystal, the elongation at break of composites increased at beginning and then decreased. The solvent resistance of composites was also improved significantly. TGA curves showed that the crystals had a little influence on the heat resistance for composites. FTIR results suggested that adding semi-organic crystal could increase the degree of hydrogen bongding of urethane carbonyl in composites. The DSC and DMA results verified that the temperature of crystal melting peak in hard segment of polyester polyurethane and polyether polyurethane/semi-organic crystal composites were improved, meanwhile the glass transition temperature (Tg) of soft segment in polyester polyurethane composites was reduced, but the glass transition temperature (Tg) of soft segment in polyether polyurethane composites was increased. It was showed that the micro-phase separation of polyester polyurethane composites was improved but polyether polyurethane composites was not. The storage modulus and loss modulus of polyester polyurethane composites was increased compared with the blank sample. The storage modulus of polyether polyurethane composites was also improved, but loss modulus improved little. It was indicated that the semi-organic crystals added reduced interior heat build-up of polyether polyurethane composites. |
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