Thermal analysis differential scanning calorimetry

The procedures of measuring changes in some physical or mechanical property as a sample is heated, or alternatively as it is held at constant temperature, constitute the family of thermoanalytical methods of characterisation. A partial list of these procedures is differential thermal analysis, differential scanning calorimetry, dilatometry, thermogravimetry. A detailed overview of these and several related techniques is by Gallagher (1992). 

Thermal Analysis - Differential Scanning Calorimetry (DSC) and thermal gravimetric analysis (TGA) were used to characterize the thermal properties of the polymers synthesized. DSC analysis was performed on a Perkin-Elmer Differential Scanning Calorimeter, Model 2C with a thermal analysis data station. Thermal gravimetric analysis (TGA) was carried out on a DuPont thermal gravimeter, Model 951. From the DSC and TGA plots of poly (N-pheny 1-3,4-dimethylene-... 

Most workers in the pharmaceutical field identify thermal analysis with the melting point, differential thermal analysis, differential scanning calorimetry,... 

A variety of techniques have been used to determine the extent of crystallinity in a polymer, including X-ray diffraction, density, IR, NMR, and heat of fusion [Sperling, 2001 Wunderlich, 1973], X-ray diffraction is the most direct method but requires the somewhat difficult separation of the crystalline and amorphous scattering envelops. The other methods are indirect methods but are easier to use since one need not be an expert in the field as with X-ray diffraction. Heat of fusion is probably the most often used method since reliable thermal analysis instruments are commercially available and easy to use [Bershtein and Egorov, 1994 Wendlandt, 1986], The difficulty in using thermal analysis (differential scanning calorimetry and differential thermal analysis) or any of the indirect methods is the uncertainty in the values of the quantity measured (e.g., the heat of fusion per gram of sample or density) for 0 and 100% crystalline samples since such samples seldom exist. The best technique is to calibrate the method with samples whose crystallinites have been determined by X-ray diffraction. 

The microanalytical methods of differential thermal analysis, differential scanning calorimetry, accelerating rate calorimetry, and thermomechanical analysis provide important information about chemical kinetics and thermodynamics but do not provide information about large-scale effects. Although a number of techniques are available for kinetics and heat-of-reaction analysis, a major advantage to heat flow calorimetry is that it better simulates the effects of real process conditions, such as degree of mixing or heat transfer coefficients. 

In this chapter, we report the results of a study of the synthesis of a more complete series of polymers, la-Ih, by the same low-temperature condensation polymerization reaction (equation 1), All these new polymers were characterized by NMR spectroscopy, gel permeation chromatography (GPC), thermal analysis (differential scanning calorimetry [DSC] and ther-mogravimetric analysis [TGA]), and elemental analysis. 

X-Ray Diffraction, Thermal Analysis (Differential Scanning Calorimetry, DSC, Thermogravimetric Analysis, TGA), and Micro-Eourier Transform Infrared Spectroscopy. 

Information on physical parameters of the molecular structure of polyamide fibers are usually obtained by x-ray diffraction methods, electron and light microscopies, infrared spectroscopy, thermal analyses such as differential thermal analysis, differential scanning calorimetry, and thermomechanical analysis, electron spin resonance, and nuclear magnetic resonance (NMR) spectroscopy. X-ray diffraction provides detailed information on the molecular and fine structures of polyamide fibers. Although the diffraction patterns of polyamide fibers show wide variation, they exhibit usually three distinct regions ... 

DTA/DSC differential thermal analysis/differential scanning calorimetry... 

The kinetics of crystallization has been simulated by many models, including the Avrami model (House 2007). The rate of conversion from amorphous to crystalline states can be measured by using thermal analysis (differential scanning calorimetry, DSC) and/or X-ray diffraction. The rate of conversion from amorphous to crystalline form depends on a number of factors. The process occurs in two steps, nucleation and growth (Mullin 2001), which are affected by various factors and occur at different rates. Specifically, for crystallization to occur, a seed or nucleus must form, on which subsequent growth will occur. Thus, the rate of nucleation is of primary interest. By analogy with Arrhenius-type processes, the nucleation rate can be written as... 

Studies of the thermal and chemical stability of polymers are of paramount importance and instrumentation used in these studies discussed in Chapter 9 include thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry, thermal volatilisation analysis and evolved gas analysis. Monitoring of resin cure is another important parameter in polymer processing in which dynamic mechanical analysis, dielectric thermal analysis and differential scanning calorimetry is used (Chapter 10). 

Thermogravimetric analysis Differential thermal analysis Differential scanning calorimetry Thermal volatiUszation analysis Evolved gas analysis Mass spectroscopy methods Matrix-assisted laser desorption/ionization Imaging chemiluminescence... 

Abstract A CaCOs filler was coated with various mono- and dicarboxylic acids in a dry-blending process. The coated fillers were characterized by various techniques, including dissolution experiments, thermal analysis (differential scanning calorimetry) and inverse gas chromatography (IGC) to determine the amount of surfactant needed to achieve mono-layer coverage IGC proved to be the most convenient, reliable and universal method for this purpose. The dispersion component of the surface tension and the specific interaction potential of the coated filler can be derived from the results, but indirect conclusions can be also drawn from them about the orientation of the molecules on the filler surface and the structure of the layer formed. The coverage of the filler with an organic compound leads to a... 

Thermal Analysis Differential scanning calorimetry was performed using a Perkin-Elmer Pyrus 1 DSC. Scan rates were 20 °C/min and carried out under a helium atmosphere. Thermogravimetric analysis was carried out using a Perkin-Elmer TGA-7 interfaced to a Pyrus Data Station. Analyses were run at 20 C/min scan rates of 20 cc/min flow of either nitrogen or air (as indicated). 

Thermal analysis. Differential scanning calorimetry (DSC) was performed by means of either the TA 2920 DSC or the Perkin-Elmer DSC-7 calorimeter. Sample weights of 8 12 mg and a heating rate of 20 °C/min were used. The glass transition... 

The observed shift of the glass transition was further analyzed by thermal analysis. Differential scanning calorimetry (DSC) was used and the results are shown in Figure 4. A similar shift to that found in the rheometer was observed. Without the frequency dependence however, the Tg was -27°C for the starting PTMC as compared to -16°C for the PC ionomer. 

Calorimetric methods can also be used to determine the crystallinity of PVA films. They include differential thermal analysis, differential scanning calorimetry (DSC), and thermogravimetric analysis. Typically, the heat of crystallization of a PVA sample, AH, is compared to the heat of crystallization of 100% crystalline PVA, AH< . The degree of crystallinity is expressed as ... 

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