Equations gordon-taylor

ET40)/PET blends, and in the 100/0 wt% P(HB80-ET20)/PET blend. This is because of either (a) a high content of rigid rod-like liquid crystalline component, or (b) an enthalpy which was too small to detect. The dependence of Tg on the blend composition can be evaluated by using the Gordon-Taylor Equation [37],... 

Glass-transition temperatures of the three diblocks and the two homopolymers are plotted against isoprene content in Figure 3. The values plotted in Figure 3 were determined by TMA at a heating rate of 5°C/min. The points fall near a straight line which can be described by a simplified version of the Gordon-Taylor equation (20) ... 

Figure 3. Tg data for PVC/PCL and NC/PCL blends plotted according to the Gordon-Taylor equation. The lines are fit to the quenched data (1).

Figure 3 shows that the Gordon-Taylor equation fits the quenched data for the PVC/PCL blends quite well. The thermograms for the blends of 25, 35, and 50% PVC display PCL heats of fusion, and conse-... 

A logarithmic form of this equation is given by Pochan et al. Other expressions include the Wood equation the Kelley-Bueche expression the Gordon-Taylor equation and the DiMarzio-Gibbs equation None of these Equations directly take into account the specific interactions within a blend. 

Fig. 7 Glass transition vs. water content relationship for amorphous indomethacin. Lines show fit to the Gordon-Taylor equation with K values of 0.33 (predicted) and 0.11...

The glass transition temperature of amorphous multicomponent mixtures can be used to determine the miscibility of the components. If the mixture is miscible, then a single glass transition temperature is usually obtained. Various equations can be used to predict the glass transition temperature of miscible mixtures. Examples include the Gordon-Taylor equation [Eq. (11)] or the Fox-Flory equation [Eq. (12)]. 

Calculated using Gordon-Taylor equation with an intrinsic glass transition, 7 of 74°C (347 K) and - 139°C (135 K) for sucrose and water, respectively, and a Gordon-Taylor constant value of 0.13675. 

The glass-transition temperature curve of the maltodextrin RD-111, MOR-REx 1910, and MOR-REX 1914 were obtained using the Gordon-Taylor equations for binary systems, according to the procedure described by Collares et al. (2004). 

Firstly the effect of on Tg of a food polymer is considered. To establish moisture content and relationship, the sorption isotherm for water/soy flour system is developed. Information of this kind is readily available in the literature for various systems (Labuza and Hyman, 1998). The Gordon-Taylor equation (Gordon and Taylor, 1952) is used to predict the effect of (using moisture content vs. relationship obtained from MSI) on Tg. The Gordon-Taylor equation has been used to predict the Tg of several binary mixtures (Roos, 1995 Morales-Diaz and Kokini, 1998). In general for most food polymers with a distribution of hydrophilic groups an increase in a results in a decrease in Tg (Slade and Levine, 1995). The Tg predicted with the Gordon-Taylor equation is used as a first part of our modification. 

Experimental Tg values as a function of moisture content predicted well with the Gordon-Taylor equation. 

Differential scarming calorimetry (DSC) was used to measure the glass transition (Tg) of samples humidified over saturated solutions of LiCl, CH3COOK, MgCl2, and K2CO3. The Gordon-Taylor equation was fitted to the glass-transition data. 

Water plasticized the food models and caused a substantial decrease of the glass-transition temperature. The Gordon-Taylor equation was successfully fitted to experimental glass transition temperatures of the three model systems, as shown in Figure 53.2b. The constant, k, for the Gordon-Taylor equation was found to be 7.6 0.8 for lactose/reactant systems, 7.2 0.7 for lactose/trehalose/reactant systems, and 7.9 0.9 for trehalose/reactant systems. The three model systems had corresponding glass-transition behaviors, which were typical of lactose-based dairy products. The critical water contents at 23°C obtained from Tg data for lactose/reactant, lactose/trehalose/reactant, and trehalose/reactant systems were 7.0, 7.4, and 7.1 g/100 g of dry solids, respectively. 

Because water plasticizes hydrophilic food components, their glass transition is strongly dependent on water content. The effect of water on the glass-transition temperature of several amorphous carbohydrates, calculated with the Gordon Taylor equation [B.79], is depicted in Fig. 6.4-6. Within the range of the materials shown, Tg decreases with lower average molecular weight and/or increased concentration of plasticizer (water). 

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