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首页> 外文会议>International Conference on "Times of Polymers and Composites" >Relations of pressure and temperature dependences of the Johari-Goldstein β-relaxation to the α-relaxation: Amorphous polymers
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Relations of pressure and temperature dependences of the Johari-Goldstein β-relaxation to the α-relaxation: Amorphous polymers

机译：Johari-goldsteinβ-松弛对α-弛豫的压力和温度依赖性的关系：无定形聚合物

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摘要

An approximate relation between the Johari-Goldstein (JG) β-relaxation time τ_(JG) and the α-relaxation time τ_α was derived and predicted to be approximately invariant to variations of pressure P and temperature T at constant τ_α. This prediction was verified in several glass-formers where τ_α and τ_(JG) were determined directly without fitting by empirical procedure. In some polymers including PMMA, 1,4 polybutadiene and polyisoprene, either the JG β-relaxation or the α-relaxation was not resolved at all P and T, and τ_α and τ_(JG) had to be obtained by fitting the spectra by some procedure. Unfortunately, in fitting the spectra, the procedure commonly used allows τ_α and τ_(JG) to vary freely and independently of each other. Consequently, the values of τ_α and τ_(JG) obtained from the fits are artifacts of the inappropriate fitting procedure, and naturally the obtained values can deviate from the predicted relation. The deviations are artificial and cannot be used to test the prediction. Another purpose of the paper is to provide better understanding of the nature of the JG β-relaxation and to elucidate how and when the approximate relation between τ_α and τ_(JG) was found.
机译：所述佐哈里-戈尔茨坦（JG）β-弛豫时间τ_（JG）和α-弛豫时间τ_α之间的近似关系，并对其进行预测为大约不变以恒定τ_α压力P和温度T的变化。这种预测在几个玻璃形成剂进行了验证，其中τ_α和τ_（JG）直接测定而不受经验程序拟合。在一些聚合物，包括聚甲基丙烯酸甲酯，1,4-聚丁二烯和聚异戊二烯，无论是βJG松弛或α-松弛完全没有P和T解决，τ_α和τ_（JG）不得不通过一些光谱拟合获得程序。不幸的是，在拟合光谱中，通常使用的程序允许τ_α和τ_（JG）自由且彼此独立地变化。因此，τ_α和τ_的（JG）从拟合获得的值是不恰当的装配过程的伪影，和天然获得的值可以从预测关系偏离。偏差是人为的，不能被用来测试的预测。本文的另一个目的是提供更好的JGβ松弛的本质的认识，并阐明τ_α和τ_（JG）之间的近似关系被发现的方式和时间。

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