Kuhn segment, glass transition temperature

FIGURE 17 The dependence of glass transition temperature T on Kuhn segment length T for PESF. 

Table 3.1 shows the chemical stmcture of the repeating units of the first series of the studied polyimides and some of their physical properties. Some of these polyimides contain methyl substituents on phenylene rings (2, 4 and 6) and other contain hexafluoroisopropylidene groups (5 and 6) in the main chain [35], Figure 3.6 presents the dependence of glass transition temperature on Kuhn segment. 

We have calculated their Kuhn segment under the assumption of free rotation (A ), characteristic ratio (CJ and Van der Waals volume (V ). These polymers were synthesized in m-cresol and the films were prepared Ifom their solutions in chloroform. Table 3.12 shows the values of glass transition temperature of the fourth series of polyimides. These values are... 

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