Differential Scanning Calorimetry and Thermogravimetry

Figure 21. Differential scanning calorimetry and thermogravimetry of oxygen chemisorption on cellulose char at 118 C. The analysis was carried out on 2.5-mg samples in aluminum pans using a Cohn R-lOO electrobalance and a DuPont calorimeter cell attached to a DuPont model 990 thermal analyzer, and nitrogen and oxygen gas flows (60 mL/min, dried by passing through H2SO4) were rapidly interchangeable for DSC and TG.

PPS shows a glass transition temperature Tg of 85-90°C and melts around 290°C. PPS is comparatively highly thermally stable. Differential scanning calorimetry and thermogravimetry indicate that the weight loss on thermal degradation starts at 430 C. Below 450°C, extensive crosslinking takes place. ... 

Karacan and Kok recently studied the pyrolysis of two crude oils and their SARA fraetions." Differential scanning calorimetry and thermogravimetry techniques were used to evaluate the pyrolysis behaviour of the feedstoeks. The results indicated that the pyrolysis mechanisms depend on the nature of the constituents. Thermogravimetric data showed that asphaltenes are the main contributors to coke formation and that resins are a second contributor. The weight loss for the SARA components was additive. The authors argued that each fraction in a whole crude oil follows its own reaction pathway and there is no interaction or S5mergy between the components. 

This chapter describes various aspects of thermal studies conducted on CaS04 2H20 and a and P forms of CaS04 /2H20, using differential thermal analysis, differential scanning calorimetry, and thermogravimetry. The effect of environmental conditions on the quantitative deterioration of the various calcium sulfate compounds is also examined. The development of more recent techniques such as controlled reaction thermal analysis is also presented.t ... 

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 methods of analysis discussed in this section are differential scanning calorimetry (DSC), thermogravimetry (TG), and hot-stage microscopy (HSM). All three methods provide information upon heating the sample. Heating can be static or dynamic in nature, depending on the information required. 

Pulse thermal analysis extends the versatility of conventional thermoanalytical methods by providing a means for studying differential reaction progresses. This advantage is combined with all the opportunities of thermogravimetry, differential thermal analysis or differential scanning calorimetry and evolved gas analysis. The primary benefits of the new method are ... 

Although water is known as a natural plasticizer for many polar polymers such as nylon, polyester resins, and cellulosic polymers, similar behavior for polyacrylamide and poly(acrylamide-co-acrylic acid) has not been investigated. In this study, the effect of water content (and/or thermal history) on the Tg s of acrylamide-based pol3 TOers was studied by Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Thermomechanical Analysis (TMA), and Simultaneous Thermogravimetry - Mass Spectrometry (TG/MS). 

This concludes the discussion of thermometry and dilatometry. The tools to measure temperature, length, and volume have now been analyzed. The tools for measurement of heat, the central theme of this book, will take the next three sections and deal with calorimetry, differential scanning calorimetry, and temperature-modulated calorimetry. The mechanical properties which involve dilatometry of systems exposed to different and changing forces, ate summarized in Sect. 4.5. The measurement of the final basic variable of state, mass, is treated in Sect. 4.6 which deals with thermogravimetry. 

The kinetics of the hydration process was studied by thermogravimetry (TG), differential scanning calorimetry, and spectroscopic methods. The time of setting of freshly prepared pastes and the compressive and bending strengths of sample beams after the 7th day and the 28th day of setting were determined. 

This paper concerns the preparation and the thermomechanical properties of environmentally compatible polymers derived from saccharides and lignins at our laboratory. The above research results have been obtained over the last several years. The environmentally compatible polymers include polyurethane (PU) and poly(8-caprolactone) (PCL) derivatives. PU derivatives were prepared from saccharides and lignins. PCL derivatives were synthesized from lignins, saccharides, cellulose and cellulose acetate. The thermal properties of the above polymers were studied by differential scanning calorimetry (DSC), thermogravimetry (TG) and TG-Fourier transform-infrared spectrometry (FTIR). Mechanical properties were measured by mechanical testing. 

Thermal analysis gives information on the fundamental behavior and structure of materials based on their thermochemical and thermophysical properties. Differential thermal analysis (DTA), differential scanning calorimetry (DSC), thermogravimetry (TG), dilatometry, and other related dynamic thermal methods serve as analytical tools for characterizing a wide variety of solid materials. Information obtainable by these methods includes phase relationships, identification and measurement of impurities in high-purity materials, fingerprint identifications, thermal histories of the material, and dissociation pressures. 

Thermal analysis iavolves techniques ia which a physical property of a material is measured agaiast temperature at the same time the material is exposed to a coatroUed temperature program. A wide range of thermal analysis techniques have been developed siace the commercial development of automated thermal equipment as Hsted ia Table 1. Of these the best known and most often used for polymers are thermogravimetry (tg), differential thermal analysis (dta), differential scanning calorimetry (dsc), and dynamic mechanical analysis (dma). 

The techniques referred to above (Sects. 1—3) may be operated for a sample heated in a constant temperature environment or under conditions of programmed temperature change. Very similar equipment can often be used differences normally reside in the temperature control of the reactant cell. Non-isothermal measurements of mass loss are termed thermogravimetry (TG), absorption or evolution of heat is differential scanning calorimetry (DSC), and measurement of the temperature difference between the sample and an inert reference substance is termed differential thermal analysis (DTA). These techniques can be used singly [33,76,174] or in combination and may include provision for EGA. Applications of non-isothermal measurements have ranged from the rapid qualitative estimation of reaction temperature to the quantitative determination of kinetic parameters [175—177]. The evaluation of kinetic parameters from non-isothermal data is dealt with in detail in Chap. 3.6. 

Fig. 7. Thermogravimetry and differential scanning calorimetry curves for corn cob xylan (Unpublished data).

This paper reviews recycling technologies of PMMA waste, its applications and its markets. It relates in detail experimentation on thermal and oxidative depolymerisation of PMMA scrap, under nitrogen and oxygen atmospheres, at different heating rates by thermogravimetry and differential scanning calorimetry techniques. 15 refs. 

Thermal analytical techniques such as thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC) have all been successfully employed in studying the pyrotechnic reactions of energetic materials such as black powder, as well as of binary mixtures of the constituents. 

The research papers which originated in the last couple of years in different countries in this field indicate that ED and Er are not generally reported and there is an emphasis on the study of comprehensive thermal behavior of explosives as a function of temperature or time by means of different thermal analytical techniques. Most commonly used methods of thermal analysis are differential thermal analysis (DTA), thermogravimetric analysis (TGA) or thermogravimetry and differential scanning calorimetry (DSC). 

Lopez-Capel, E., Sohi, S., Gaunt, J. L., and Manning, D. A. C. (2005b). Use of thermogravimetry-differential scanning calorimetry to characterize modelable soil organic matter fractions. Am. J. Soil Sci. Soc. 69, 3192-3198. 

The thermal characterisation of elastomers has recently been reviewed by Sircar [28] from which it appears that DSC followed by TG/DTG are the most popular thermal analysis techniques for elastomer applications. The TG/differential thermal gravimetry (DTG) method remains the method of choice for compositional analysis of uncured and cured elastomer compounds. Sircar s comprehensive review [28] was based on single thermal methods (TG, DSC, differential thermal analysis (DTA), thermomechanical analysis (TMA), DMA) and excluded combined (TG-DSC, TG-DTA) and simultaneous (TG-fourier transform infrared (TG-FTIR), TG-mass spectroscopy (TG-MS)) techniques. In this chapter the emphasis is on those multiple and hyphenated thermogravimetric analysis techniques which have had an impact on the characterisation of elastomers. The review is based mainly on Chemical Abstracts records corresponding to the keywords elastomers, thermogravimetry, differential scanning calorimetry, differential thermal analysis, infrared and mass spectrometry over the period 1979-1999. Table 1.1 contains the references to the various combined techniques. 

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