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电子自旋共振(ESR)研究表明: (1)在真空中γ-辐照F_(46)产生的俘获自由基暴露于空气后逐渐转化成过氧化自由基,其常温ESR谱为单峰,g=2.0148±0.0009,ΔH_(PP)=18.9±1.5G. (2)F_(46)真空中俘获自由基的自氧化反应是一个既受氧的扩散速度控制,又与自由基浓度有关的双因素控制的过程,而与自氧化反应的速度常数无关. (3)氧在γ-辐照F_(46)中的扩散系数与自由基浓度有关,而与自由基种类无关.在自氧化过程中位于晶区的仲碳自由基…CF_2-CF-CF_2…从晶区内部快速“转移”到晶区表面与氧反应. (4)以ESR方法用单纯扩散动力学公式测定的氧在全氟型高聚物中的扩散系数,一般是以自由基浓度为函数的表观扩散系数,仅当自由基浓度足够低时(对于本文所采用的悬浮法F_(46)薄膜样品而言,n≤2×10~(17)spins/g)才能求得接近未辐照样品时的真实扩散系数. (5)用本法求得氧在悬浮法F_(46)薄膜中的扩散系数D=1.6×10~(-7)cm~2/sec(20℃).
Electron spin resonance (ESR) studies showed that: (1) The free radical generated by γ-irradiation F_ (46) in vacuum evolved into peroxide radical after being exposed to air, the ESR spectrum at room temperature was single peak, g = 2.0148 ± 0.0009, ΔH_ (PP) = 18.9 ± 1.5G. (2) The autoxidation of free radicals in F_ (46) vacuum was a two-factor (3) The diffusion coefficient of oxygen in γ-irradiation F_ (46) is related to the concentration of free radicals, but not to the type of free radicals. In the process of self-oxidation, Secondary carbon radical in the crystal region ... CF_2-CF-CF_2 ... rapidly “translocates” from the interior of the crystal to the surface of the crystal region and reacts with oxygen. (4) Oxygen measured by simple diffusion kinetic equation The diffusion coefficient in the polymer is generally an apparent diffusion coefficient as a function of free radical concentration, only when the free radical concentration is low enough (for suspension F_ (46) film samples used herein, n≤2 x 10 ~ (17) spins / g) to get the true diffusion coefficient close to the non-irradiated sample. (5) Obtained by this method oxygen in suspension F_ (46) film The diffusion coefficient of D = 1.6 × 10 ~ (-7) cm ~ 2 / sec (20 ℃).