Thermogravimetric analysis thermomechanical properties

Thermal analysis is well suited for characterizing and identifying plastics, as their properties are temperature dependent. It involves methods in which the substance is subjected to a controlled temperature program and the changes in the physical and chemical properties are measured as a function of temperature or time. The ambient atmosphere also influences the properties of plastic. Thermal analysis comprises traditional techniques differential scanning calorimetry (DSC), differential thermal analysis, thermogravimetric analysis, thermomechanical analysis, and more recent methods pressure differential scanning calorimetry, dynamic mechanical analysis, and differential photocalorimetry. 

Three carbon fibre-reinforced polyimides were exposed to UV radiation at 177C, at three different intensities for three different times, so that the product of intensity and time was a constant. Intensities of 1,2 and 3 suns, where one sun is the power in space at one earth-sun distance, were used, for a time periods of 500, 250 and 167 h. The samples were characterised by X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis, thermomechanical analysis and dynamic mechanical analysis. Measurement of bulk properties showed no difference between samples exposed to heat and UV radiation, and control samples. Surface analysis by XPS showed an apparent decrease in carbonyl concentration on the surface of some exposed samples. This was correlated to surface contamination by a silicone-containing material. 3 refs. 

Major instrumentation involved with the generation of thermal property behavior of materials includes thermogravimetric analysis (TG, TGA), DSC, differential thermal analysis (DTA), torsional braid analysis (TBA), thermomechanical analysis (TMA), thermogravimetric-mass spectrometry (TG-MS) analysis, and pyrolysis gas chromatography (PGQ. Most of these analysis techniques measure the polymer response as a function of time, atmosphere, and temperature. 

Another type of calorimetric technique is called thermogravimetric analysis (TGA). It is the study of the weight of a material as a function of temperature. The method is used to evaluate the thermal stability from the weight loss caused by loss of volatile species. A final example, thermomechanical analysis (TMA), focuses on mechanical properties such as modulus or impact strength as a function of temperature. Both types of analysis are essential for the evaluation of polymers that to be used at high temperatures. 

The analytical techniques used to study changes in physical properties with temperature are called thermal analysis techniques. They include thermogravimetric analysis (TGA), differential thermal analysis (DTA), differential scanning calorimetry (DSC), thermometric titration (TT), and direct injection enthalpimetry, dynamic mechanical analysis (DMA), and thermomechanical analysis (TMA). Thermal analysis techniques are used in... 

Thermoanalytical (TA) methods characterize a system in terms of the temperature dependency of its thermodynamic properties and the physiochem-ical reaction kinetics of TPs and TSs. The techniques reviewed here only include differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and thermomechanical analysis (TMA). Others also are available, which are useful in the processing plant (1, 2). 

The softening point, coefficient of expansion and other thermomechanical properties can be determined using thermomechanical analysis (TMA). In addition, thermal stability can be determined by thermogravimetric analysis (TGA). While in vivo exposure normally occurs at 37.4°C, these tests... 

Information on standard methods for the determination of the properties of polymers is reviewed in Table 4.1. General reviews of the determination of thermal properties have been reported by several workers [1-6]. These include application of methods such as dynamic mechanical analysis [5], thermomechanical analysis [5], differential scanning calorimetry [4], thermogravimetric analysis [6], and Fourier transform infrared spectroscopy [4], in addition to those discussed below. 

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