Crystalline morphology in thin films of natural rubber II. Crystallization under strain
Crystalline morphology in thin films of natural rubber II. Crystallization under strain
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DOI：
10.1098/rspa.1964.0040
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发表时间：
1964-02
期刊：
影响因子：
--
通讯作者：
E. H. Andrews
中科院分区：
文献类型：
--
作者：
E. H. Andrews
用电子显微镜观察了单向应变下结晶的天然橡胶薄膜的形态。随着应变的增加，未应变薄膜的球晶形态逐渐让位于纤维状形态，其中结晶细丝（α细丝）测量为60 × 250 μ m，垂直于应变轴生长。这些细丝的成核由应变量决定，但它们的生长速率仅取决于温度和时间。在非常高的应变（> 300%）下，结晶迅速发生，不允许长丝生长，因此所得形态由沿延伸方向延伸的核链（γ长丝）组成。从α到γ细丝的高应变转变并不伴随着电子衍射图案的变化，但是从球晶到细丝生长的早期转变揭示了分子轴向应变方向的旋转。这似乎与α纤维围绕其生长方向的物理旋转相对应。
The morphology of thin films of natural rubber crystallized under unidirectional strain has been examined in the electron microscope. As strain increases the spherulitic morphology of unstrained films gives way gradually to a fibrillar morphology with crystalline filaments (α filaments) measuring 60 by 250 Å, growing perpendicular to the strain axis. The nucleation of these filaments is governed by the amount of strain but their rate of growth depends only on temperature and time. At very high strains ( > 300 %) crystallization occurs rapidly allowing no time for filament growth, so that the resulting morphology consists of chains of nuclei (γ filaments) running in the direction of extension. The high strain transition from α to γ filaments is accompanied by no change in the electron diffraction pattern, but the earlier transition from spherulitic to filamentous growth reveals a rotation of the molecular axis into the direction of strain. This appears to correspond to a physical rotation of the α filaments about their direction of growth.