成核
材料科学
复合材料
结晶
纤维
形态学(生物学)
临界半径
增长率
球晶(高分子物理)
半径
聚丙烯
Crystal(编程语言)
图层(电子)
光学显微镜
熔点
扫描电子显微镜
聚合物
化学工程
热力学
几何学
物理
工程类
遗传学
数学
曲率
计算机安全
生物
计算机科学
程序设计语言
标识
DOI:10.1002/(sici)1099-0488(19960115)34:1<47::aid-polb2>3.0.co;2-t
摘要
Transcrystallization of polypropylene (PP) on the polytetrafluoroethylene (PTFE) fiber was investigated. Both nucleation rate and crystal growth rate were determined by a polarized optical microscope. Based on the theory of heterogeneous nucleation, it has been found that the induction time can correlate well with the nucleation rate in determining the interfacial free energy difference function Δσ. The ratio of Δσ in the bulk matrix to that at the interface is 1.63 which implies the transcrystalline growth is favorable from a thermodynamic point of view. No difference in crystal growth rate of PP has been found in either spherulites or transcrystalline layers. On the basis of regime theory, a transition between regimes II and III was observed at ΔT = 48K. From the morphology studies, it has been found that the thickness of the transcrystalline layer increases with crystallization temperature, from 30 to 120 μm in the temperature range of 110–140°C. The growth of transcrystalline layer is hindered by the spherulites nucleated in the bulk. Moreover, the radius of spherulites adjacent to the transcrystalline layer is much smaller than that distant to the fiber. No significant increase in nucleation density at fiber ends is observed. Effect of internal stresses of fibers on the fiber's nucleating ability is not pronounced. © 1996 John Wiley & Sons, Inc.
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