Inflection temperature

The two different temperature regimes of occurring below 7a are separated from each other by a precisely determined crossover temperature T) (denoted by crosses in Fig. 6), which is defined by an inflection point in the product J c(T ) T as a function of T. As discussed later, this crossover or inflection temperature T) appears to conform to the phenomenology of the experimentally estimated mode coupling temperature T p (denoted also as T] ). 

Tabulate the extrapolated onset and peak or inflection temperatures for all transitions, (see Fig. 16.3). 

The temperature dependence of the relaxation modulus at 500 seconds of polycarbonate (7), polystyrene (8), and their blends (75/25, 50/50, and 25/75) was obtained from stress-relaxation experiments (Figure 4, full lines). In the modulus-temperature curves of the blends, two transition regions are generally observed in the vicinity of the glass-rubber transitions of the pure components. The inflection temperatures Ti in these transition domains are reported in Table I they are almost independent on composition. The presence of these two well-separated transitions is a confirmation of the two-phase structure of the blends, deduced from microscopic observations. 

Mean Linear Thermal Expansion Coefficients (ou) and Inflection Temperatures T of Nafion Membranes... 

The derivative given by equation (6-67) is positive for all T, C, and the [—r T)] curve corresponding cannot have any maximum. There is, however, an inflection point of equation (6-65) corresponding to an inflection temperature, T, defined by... 

When the 6 value was higher than 0c. the incident pulse was totally reflected at the interface between the PS and S-LAH79 substrate. That is, the NBD dye molecules near the interface were selectively excited by the evanescent wave. Hence, the data set obtained at 0 = 53.6° reflects the interfacial molecular motion. The inflection temperature, which can be assigned to the interfacial Tg (7 ) at 0 = 53.6°, was 386 K, and was discemibly higher than the T. This is direct evidence for depressed mobility at the interface. 

Figure 5.17. WLF shift factor curve for the data of Fig. 5.15 reference temperature Ti (the inflection temperature) is equivalent to Tg. Note that Q and C2 here are not the universal values but are specific for the polycarbonate polymer. [From Mercier et al. (1965) reprinted with permission of John Wiley and Sons, Inc.]...

Inspection of Figure 5 shows a very broad glass-to-rubber transition range which extends from below -100°C to above 0°C for the polyurethane adhesive. The relaxation modulus E(t) - 400 Kg/cm which occurs at the rubbery inflection temperature - 40°C - 313 K describes an effective molecular weight M as defined by kinetic theory of rubber elasticity ... 

The Tg values of the prepared polyimides were determined from the inflection temperature of the storage modulus E, measured by dynamic mechanical analysis (DMA). The Tg values moved towards higher temperature in the order of PI-s-BPDA < PI-a-BPDA < PI-i-BPDA for example, Tg values of PI-(s-BPDA/4,4 -ODA), PI-(a-BPDA/4,4 -ODA) and PI-(i-BPDA/4,4 -ODA) from4,4 -ODA were 262°C, 319°C and 330°C, respectively (Figure 7.5). 

Plasticizer in Dry blend Inflection Temperature (°C) Dry Peak Temperature (°C)... 

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