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首页> 外文期刊>Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites >Cold drawing of polymers: Plasticity and aging
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Cold drawing of polymers: Plasticity and aging

机译：聚合物冷拔：可塑性和老化

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Physical aging and mechanical deformation on polyisobutylmethacrylate (PIBMA) and polymethylmethacrylate (PMMA) have been investigated below but close to the glass transition temperature using calorimetry and elastic neutron scattering. We have studied the effect of physical aging before, during and after the deformation on the mechanical, thermal responses combined to a structural analysis ranging from the radius of gyration to the monomeric scales. On one hand we report that, as expected, plastic strains rejuvenate glassy polymer aged before drawing, and also that no aging effect occurs during the plastic deformation. Moreover, the enthalpic relaxation functions as measured by calorimetry on aged samples, before and after stretching, remain quite similar. On the other hand, we find that stretching a glassy chain induces a strong anisotropy at large scale, around the radius of gyration. This anisotropy disappears gradually at smaller scale down to the monomer structure. However, while the anisotropy is lost at the local scale, the static structure factor is still altered by the plastic strain. Theses changes at the monomer scale may be responsible of the complete loss of thermal history operated before stretching. The cold-drawn sample posses a slightly modified structure leading to a distinct glassy state which enthalpic relaxation remains unaltered. So plastic deformations do not simply rejuvenate a glassy polymer, it induces a 'metamorphosis'. (c) 2006 Elsevier B.V. All rights reserved.
机译：下面通过量热法和弹性中子散射法研究了聚甲基丙烯酸异丁酯（PIBMA）和聚甲基丙烯酸甲酯（PMMA）的物理老化和机械变形，但接近玻璃化转变温度。我们研究了变形之前，之中和之后的物理时效对机械，热响应的影响，并结合了从回转半径到单体尺度的结构分析。一方面，我们报告，正如预期的那样，塑性应变使拉丝之前老化的玻璃态聚合物恢复活力，并且在塑性变形过程中没有发生老化效应。此外，在拉伸之前和之后，通过量热法对老化样品的焓弛豫功能仍然非常相似。另一方面，我们发现拉伸玻璃状链会在回转半径附近引起较大的各向异性。直到单体结构，这种各向异性以较小的比例逐渐消失。然而，尽管各向异性在局部尺度上消失了，但是静态结构因子仍然被塑性应变所改变。这些在单体尺度上的变化可能是拉伸前完全失去的热历史的原因。冷拉样品的结构略微改变，导致明显的玻璃态，焓变保持不变。因此，塑性变形不会简单地使玻璃状聚合物恢复活力，而是会引发“变形”。 （c）2006 Elsevier B.V.保留所有权利。

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