| Summary: | 碩士 === 國立成功大學 === 化學工程學系 === 105 === In this study, the polymorphism of isotactic polypropylene composites filled with electrospun isotactic polystyrene fibers were characterized by simultaneously small-/wide angle X-ray scattering (SAXS/WAXS). The crystallinity (Φc), the content of -form iPP crystal (Kβ), long period (LB、Lc) and lamellar thickness (lc) of the iPS/iPP composites can be obtain.
iPS fibers are capable of inducing β-form crystal of iPP. When the concentration of iPS fiber in composites is 0.1 wt%, Kβ of composites increased with the addition of iPS fibers. The long period LB, Lc of composites increased about 2.5 nm after the long period of neat iPP. However, when the addition concentration of iPS fibers is larger than 0.1 wt%, Kβ, LB and Lc didn’t increased with the increasing concentration of iPS fibers. There are two different methods (MA and MB) for preparation of iPS/iPP composites. The Kβ, LB and Lc of composites which were prepared by MA are larger.
From dynamic cooling thermal treatment, it was found that the higher cooling rate, the more content of β-form crystal in composites. When MA0.1 underwent the cooling rate of 60 oC/min, Kβ can reach 0.5. However, when MA0.1 underwent the cooling rate of 2 oC/min, the LB and Lc of composites are larger.
From isothermal crystallization thermal treatment, when the isothermal temperature (Tc) is 120 oC, the content of β-form crystal in composites is about 0.55. For Tc= 125 oC, its Kβ is about 0.5 and its LB and Lc are the longest comparing the composites isothermaling at different isothermal temperature.
Through SAXS and WAXS, the internal structure of 8 wt% iPP and 4/4 wt% iPP/sPP aligned electrospun fibers were characterized. By variable-temperature SAXS and WAXS, the crystal variation of these two fibers was investigated. The annealing effect on the structure evolution can studied as well.
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