Variation of glass transition temperature with

The Teflon AF family consists of copolymers of tetrafluoroethylene, (TFE) and 2,2-bis-trifluoromethyl-4,5-difluoro-l,3-dioxole, (PDD), whose structure is shown in Figure 2.1. The properties of these amorphous copolymers vary with the relative amounts of the comonomers. At present the two commercial grades of Teflon AF are AF-1600 and AF-2400 with glass transition temperatures of 160 and 240°C respectively. The variation of glass transition temperature with composition is shown in Figure 2.2. Thus AF-1600 and AF-2400 contain 64 and 83 mol % PDD, respectively. 

Figure 9.27 shows the influence of nano-clay incorporation on storage modulus of the epoxy nanocomposites. The increase in percentage of nano-clay in epoxy resin increases the storage modulus up to a certain weight fraction of nano-clay, above which it decreases the modulus, but it is still above the value of neat epoxy matrix. The loss modulus curve shows the variation of glass transition temperature with respect to nanoclay incorporation and the maximum value of glass transition temperature is noted for the clay content of 3 wt% [31]. 

Fig. 73. Variation of glass-transition temperature with PCL content in blends of PCL with SAN-25 and PC (PCL contents defined as parts per hundred of SAN-25 plus PC),SAN-25/PC ratio 1 3 taken from [43]...

Figure 2. Variation of glass transition temperature with composition for the PI/PEl molecular composites.

Figure 19 Variation of glass transition temperature with composition for solutions of polystyrene in styrene monomer. The lines represent calculations from the Gibbs-DiMarzio lattice model upper line calculation allows for holes while the lower...

Fig. 77. Variations in glass-transition temperatures with PCL content in ternary blends of PCL with PC and phenoxy (PC/phenoxy ratio (w/w) 1 1), upper points are from the PC-rich phase taken from [166]...

Dynamic thermal mechanical analysis indicates significant broadening of glass transition temperature at or around PU/EP composition of 70/30. This is true for all three groups studied. At this composition, storage modulus showed much less steep variations with temperature during the transition from glassy to rubbery state. 

On the basis of this relatbn. Fox and Loshaek (32) developed a relation for the variation of the glass transition temperature with molecular weight. Subsequently, Gibbs and DiMarzio (34) have shown that while B is not precisely constant, it is very nearly so over a wide range of molecular weights. 

Figure 13, Variation of the glass transition temperature with polymer fraction in Se-S and Se-Te alloys (9)...

Table 17.2 Variation in glass transition temperature Tg [°C] of PSAs with UV dose.

Figure 10.31. Evolution of glass transition temperature Tg and variation in heat capacity Cp with increasing NR [STA 06]...

The rate of variation of the glass transition temperature with the degree of cure can be experimentally determined by differential scanning calorimetry. Theoretical models accounting for the influence of the degree of cure on die polymer glass transition can be also used (48) ... 

Fig. 64. Dependence of melting temperature (T ) and glass-transition temperature of PCL/PMHS blends (O) with weight fraction of PCL, crystallised at 30° C dashed line is calculated from Eq. (23). Also included is the variation in glass-transition temperature for PCL/P4HS blends data taken from [130] figure taken from [91]...

AU these equations describe to a greater or lesser degree of accuracy the variation of the glass transition temperature with composition. 

By a variation of chemistry and/or chain length the different time regimes can be shifted. From a simulation point of view we are again faced by the decision what kind of information we want to get out of the simulation. If one wants to look at very local properties, depending on the local chemistry of the individual monomers, there is no way around a simulation with all chemical details. However, one should keep in mind that by such a technique it is impossible to equilibrate the system near the glass transition temperature. 

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