Determination of glass transition

As appHed to hydrocarbon resins, dsc is mainly used for the determination of glass-transition temperatures (7p. Information can also be gained as to the physical state of a material, ie, amorphous vs crystalline. As a general rule of thumb, the T of a hydrocarbon resin is approximately 50°C below the softening point. Oxidative induction times, which are also deterrnined by dsc, are used to predict the relative oxidative stabiHty of a hydrocarbon resin. 

Several new thermal analytical techniques are potentially valuable for the study of second-order transitions in the characterization of amorphous solids and for the accurate determination of glass transition temperatures. These modem techniques can detect and characterize glass transitions and other second-order transitions that are not detectable by conventional thermal analytical techniques such as DSC, TGA, or TMA. 

Fig. 1 9 Determination of glass transition and crystalline melting temperatures by changes in specific volume.

Fig. 4.8.10. Schematic DSC curve illustrating the determination of glass transition temperature...

There are various techniques available for the determination of glass transition temperatures as are outlined below. 

Other successful determinations of glass transition temperatures by inverse gas chromatography indude those of Perrault et al. 22) on poly(butadiene), Nakamura et al 26) on cellulose triacetate and Cahigaru et id. 27) on poly(viiq l acetate). 

Abbreviations DEA, dielectric analysis >OC. degree of crystallinity DSC, di erential scanning calorimetry LM, local mobility (secondary relaxations) SR, structural relaxation 7g, determination of glass transition temperature TSDC. thermally stimulated depolarization current spectroscopy XRD, X-ray difTractometry. Source Adapted from Ref. 15. 

FIGURE 8.12 Relationships between and temperature of heat-treatment of wood powder of fir. Determination of glass transition from curves. = initial temperature of glass transition = middle temperature of glass transition. 

Plastics - Thermomechanical analysis (TMA) - Determination of linear thermal expansion coefficient and glass transition temperature Plastics - Thermomechanical analysis (TMA) - Determination of softening temperature Plastics - Determination of dynamic mechanical properties -General principles Plastics - Dynamic mechanical analysis - Determination of glass transition temperature Plastics - Dynamic mechanical analysis - Calibration... 

Standard test method for assignment of the glass-transition temperatures hy differential scanning calorimetry or differential-thennal analysis Methods of test for determination of glass-transition temperature of electrical insulating materials... 

ALE Alessi, P., Cortesi, A., Kikic, I., and Vecchione, F., Plasticization of polymers with supercritical carbon dioxide experimental determination of glass-transition temperatures, J. 

These quantities are used to determine the glass transition. A schematic comparison between a first order phase transition and the glass transition is depicted in Figure 9. Figure 10 brings an example for determination of glass transition temperature and melting temperature from isobaric V-T data. 

Williams, R.J. (1994). Methods for Determination of Glass Transitions in Seeds. Annals of Botany, Vol.74, pp. 525-530. 

Plastics—The Acquisition and Presentation of Comparable Single-Point Data Plastics—Determination of the Burning Behaviour of Specimens Using a 500 W Flame Source Plastics—Differential Scanning Calrimetry (DSC)—Part 2 Determination of Glass Transition Temperature... 

Main applications of thermal analysis are (1) Soil and clay analysis (2) Determination of Glass transition (3) Compositional effects on glass transition (4) Heat capacity determination (5) Characterization of polymer blends (6) Study the effects of additives added to polymer (7) Polymer degradation analysis (8) Crystallinity and crystallization rate study and (9) Reaction kinetic studies. 

The emulsion polymerisation of vinyl acetate-ethylene copolymers using emulsion stabilisers based on diisocyanate chain extended polyethylene glycol was compared with emulsion polymerisation using conventional stabilisers. The prepared polymers were characterised by determination of glass transition temperatures and by dynamic mechanical investigations. 5 refs. 

Figure 4.1 Determination of glass transition temperature (a) step change before and after transition (b) step change with a small peak before and after transition...

Repeatability Duplicate determinations of glass transition temperatures on two specimens of the same sample by the same analyst should not differ by more than 2.5 °C. 

In order to investigate miscibility and phase behavior of polymer blends, differential scanning calorimetry (DSC) has been frequently used for determination of glass transition temperature, crystalline melting temperature and other thermal properties. 

EN 12614 Products and systems for the protection and repair of concrete structures. Test methods. Determination of glass transition temperatures of polymers. 

Differential scanning calorimetry, thermomechanical analysis, dynamic mechanical analysis, differential thermal analysis, dielectric thermal analysis, infrared and NMR spectroscopy, are some of the instrumental techniques that have been applied to the determination of glass transition and other transition temperatures in polymers (Chapter 13). 

Thermomechanical Analysis. The equipment used in thermomechanical analysis (TMA) is similar in principle to that for TD, but provision is made for applying various types of load to the specimen, so that penetration, extension, and flexure can be measured. This approach to analyzing such modes of deformation is illustrated schematically in Figure 15. The technique finds most use in polymer studies, as in the determination of glass-transition and softening temperatures for thin films and shrinkage characteristics of fibers. 

ISO 11357-2 1999. (1999). Plastics. Differential scanning calorimetry (DSC) - part 2 Determination of glass transition temperature. International Standards Organization. 

Riesen, R., Schawe, J. (2003). The glass transition temperature measured by different TA techniques. Part 2 Determination of glass transition temperatures. UserCom, 18(2), 2-5. 

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