Syndiotactic polypropylene(sPP) as-spun fiber(sPP1) and drawn fiber(sPP2) were prepared by melt-spinning and melt-spinning/hot-drawing,respectively.The structure transition of the two fibers induced by annealing at different temperatures and the corresponding mechanical properties were subsequently investigated by the combination of Fourier transform infrared spectroscopy(FTIR),wide-angle X-ray diffraction(WAXD) and tensile testing.The results indicate that the chain conformation and crystal forms of the two sPP fibers are not obviously changed at low annealing temperature (40℃).With increasing the annealing temperature,the trans-planar conformation and mesophase in sPP1 and sPP2 fibers can be completely transformed to helical conformation and crystal form I under tension.Upon removing the tension,a small amount of mesophase and trans-planar conformation will be regained.The mechanical properties of the annealed fibers are manifestly dependent on their initial structure and the annealing temperature.
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机译:available Utilization on Hardwoods Growing in southern Kyushu : VIII. some Variation of mechanical properties and Utilization in Iju-Wood (shima wallichii ssp. liukiuensis Bloemb)