Free Volume Relaxation in Polymer Blends by the Magnetic Resonance

通过磁共振研究聚合物共混物的自由体积弛豫

• 批准号: 04805091
• 负责人: SHIMADA Shigetaka
• 金额: $ 1.15万
• 依托单位: Nagoya Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04805091/
• 关键词: Free Volume; Electron Spin Resonance; Spin Label; Molecular Miscibility; Polymer Blend; Polymer Surface; Molecular Motion; Mechanical Fracture

1. The electron spin resonance (ESR) line shape of nitroxide radical labeles attached to poly(ethylene oxide) (PE0) in a blend with isotactic poly(methyl methacrylate)(PMMA) was studied as a function of aging and annealing temperatures. The ESR line shapes of the nitroxide radical labeles attached to PMMA and the nitroxide probe in the blend were also studied. Two spectral components with different rates of motion -a "fast" component and a "slow" component are observed. The fractional amount of the fast component observed at room temperature changes with aging and annealing temperatures. The mobile fractions decrease around -20ﾟC with decreasing aging temperatures, whereas the fractions increase abruptly around 55ﾟC with increasing annealing temperatures.The specific volume of the blend was measured at room temperature by the dilatometric method. C.a.0.5% of volume contraction and expansion during aging and annealing at the same temperatures mentioned above. These experimental facts are attributed to relaxational phenomena related with annihilation and formation of free volume in an amorhous region of the blend.2. The chain end radical of polyethylene (PE) molecules anchored on a fresh polymer surface was produced by block copolymerization of ethylene which was initiated by mechano-radicals formed by mechanical fracture of a poly(tetra fluoroethylene) and located on the fresh surface. The molecular motion of the radical allows free rotation around the C-C bond axis even at 77K.The high mobility of the radical is attributed to weak intermolecular interaction, because of extremely low concentration of the PE chains on the surface, isolated from PTFE chains. In other words, the free volume of the PE phase on the PTFE surface is extremely large.

1.研究了聚环氧乙烷（PE 0）与等规聚甲基丙烯酸甲酯（PMMA）共混物中氮氧自由基的电子自旋共振（ESR）谱线形状随老化和退火温度的变化。研究了PMMA上的氮氧自由基标记物和共混物中氮氧探针的ESR谱线形状。观察到两个具有不同运动速率的光谱分量-“快”分量和“慢”分量。在室温下观察到的快速组分的分数随着老化和退火温度而变化。随着老化温度的降低，移动的分数在-20 ℃左右减少，而随着退火温度的升高，在55 ℃左右突然增加。C.a.0.5%的体积收缩和膨胀在老化和退火过程中在上述相同的温度。这些实验现象归因于与共混物非晶区的湮灭和自由体积形成有关的弛豫现象.聚乙烯（PE）分子的链端自由基锚定在新鲜的聚合物表面上，通过乙烯的嵌段共聚产生，所述乙烯由聚四氟乙烯的机械断裂形成的机械自由基引发，并位于新鲜的表面上。自由基的分子运动允许自由基在77 K下围绕C-C键轴自由旋转，自由基的高迁移率归因于弱的分子间相互作用，因为表面上的PE链浓度极低，与PTFE链隔离。换句话说，PTFE表面上PE相的自由体积非常大。

项目成果

Shigetaka Shimada: "Spin Label Study of the Free-Volume Relaxation in a Poly(ethylene oxide)/Poly(methyl methacrylate) Blend" Macromolecules. 25. 2771-2773 (1992)

Shigetaka Shimada：“聚环氧乙烷/聚甲基丙烯酸甲酯混合物中自由体积弛豫的自旋标签研究”大分子。

Masato Sakaguchi: "ESR Study on Molecular Motion of Chain End Radicals of Polyethylene Molecules Anchored on Fresh Surfaces of Polyethylene and Polytetrafuluoroethylene." Macromolecules. 26. 2612-2615 (1993)

Masato Sakaguchi：“锚定在聚乙烯和聚四氟乙烯新鲜表面上的聚乙烯分子链端自由基分子运动的 ESR 研究。”

Shigetaka Shimada: "Free-Volume Studies on Molecular Dynamics of Polymer Chains in Multiphase Systems" Research Reactor Institute Technical Report, Kyoto University. 383. 31-37 (1993)

Shigetaka Shimada：“多相系统中聚合物链分子动力学的自由体积研究”研究堆研究所技术报告，京都大学。

Shigetaka Shimada: "ESR Studies on Molecular Motion and Chemical Reactions in Solid Polymers in Relation to Structures" Progress in Polymer Science. 17. 1045-1106 (1992)

Shigetaka Shimada：“固体聚合物分子运动和化学反应与结构相关的ESR研究”高分子科学进展。

Shigetaka Shimada: "Spin Label Study of the Free-Volume Relaxation in a Poly(ethylene oxide)/Poly(methyl methacrylate)Blend" Macromolecules. 25. 2771-2773 (1992)

Shigetaka Shimada：“聚环氧乙烷/聚甲基丙烯酸甲酯混合物中自由体积弛豫的自旋标签研究”大分子。