Dependences of ts, s and K on AT T — Tg

In Fig. 14.14, the s data points of samples A, B and C as a function of AT are shown to fall closely on the same curve. The AT dependence of s of the three samples can be collectively well fitted to a modified VTF form  

The consistency of the AT dependences of s and ts individually falling on the same curves implies that the same consistency should be applicable to K as well according to Eq. (14.11) indeed so as illustrated in Fig. 14.15. The AT dependences of K of samples A, B and C can be collectively fitted to the VTF equation of the form given by Eq. (14.12) with 

It is remarkable that the ts, s and K data points of samples A, B and C as a function of AT individually fall naturally on the same curves as shown in Figs. 14.13, 14.14 and 14.15, respectively. These results suggest a Tg-related universality. Although there are only three samples involved, such universality can indeed be claimed within the polystyrene system, because of the universal nature of the elements involved in the quantitative analyses of the J t) results of the three samples. These elements have been studied in diverse parts of Chapters 9-11 and this chapter they are summarized here (1) The validity of the ERT and the universality it represents have been well tested as presented in Chapters 10-11. The success of the ERT is further summarized in Sec. 14.7 with the additional supports obtained from the study presented in this chapter. The success of the ERT being crucially testified to by the molecular-weight independence of K, there is no limit to the time range of J t) that can be analyzed, depending on the molecular 

A comment should be made about the contamination by residual plasticizers in sample B. Its Tg value is determined by the criterion ts = 1,000 sec for the sample as it is at the same time, the obtained quantities ts, s and K are also associated with sample B as it is. Because the contamination is at a very low level, the T -related dynamic process of sample B is dominated by the characteristics of polystyrene. Thus, the results of Ts, s and K as a function of AT = T — Tg of sample B as shown in Figs. 14.13, 14.14 and 14.15 can be regarded as equivalent to those of a normal sample B . 

On the basis of the universal nature of three elements explained above, the common curves of ts, s and K shared by samples A, B and C can be regarded as representing a Tg-related universality applicable within polystyrene system, entangled or not. As shown below, departure from 

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