共聚物
材料科学
聚苯乙烯
延伸率
苯乙烯
变形(气象学)
小角X射线散射
复合材料
垂直的
各向同性
圆柱
微观结构
各向异性
聚合物
几何学
光学
散射
极限抗拉强度
物理
数学
作者
Joanna Stasiak,Adam M. Squires,Valeria Castelletto,Ian W. Hamley,Geoff D. Moggridge
出处
期刊:Macromolecules
[American Chemical Society]
日期:2009-06-26
卷期号:42 (14): 5256-5265
被引量:39
摘要
Two styrene−isoprene−styrene block copolymers Vector 4111 and 4113, exhibiting cylindrical (18 wt % PS) and spherical (16 wt % PS) morphology, respectively, have been examined under uniaxial elongation up to 200% strain. On the basis of stress−strain data, mechanical properties are compared for isotropic and oriented polystyrene domains. The structure at various stages of deformation has been determined from SAXS patterns in three planes and two principal deformation directions with respect to orientation. Samples showed a very high degree of hexagonal packing, resulting in an X-ray pattern taken parallel to the cylinder alignment approaching single crystal ordering. Cylinders were aligned with the closest packed planes parallel to film surface. Particular attention has been paid to a lattice deformation process occurring during the first stretching and relaxation cycle. For a copolymer with oriented cylindrical morphology the deformation was affine up to 120% strain. The microdomain spacing was calculated parallel and perpendicular to the stretching direction. The cylindrical microstructure orientation, quantified by Hermans’ orientation factor reduced during elongation of oriented polymer, while the elongation of isotropic sample caused an increase of orientation. Deformation of all studied morphologies was reversible.
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