Differential scanning calorimetry-thermal

Differential Scanning Calorimetry. Thermal analysis of PVME/PS blends and IPNs by DSC indicates only one glass transition temperature, which is located between the homopolymer T s. The position of Tg is dependent upon composition although it does not follow the prediction of the Fox equation (21), Table II. The breadth of the transition also increases significantly with increased PS content for the blends and IPNs. The broad transition might result from either the clustering of like mers near... 

DSC-TGA (differential scanning calorimetry-thermal gravimetric analysis)... 

This book describes the applications of important new NMR spectroscopic methods to a variety of useful materials and compares them with results from other techniques such as adsorption, differential scanning calorimetry, thermally stimulated depolarization cmrent, dielectric relaxation spectroscopy, infrared spectroscopy, optical microscopy, and small-angle and wide-angle x-ray scattering. The text explores the application of NMR spectroscopy to examine interfacial phenomena in objects of increasing complexity, beginning with immodified and modified silica materials. It then describes properties of various mixed oxides with comparisons to individual oxides and also describes carbon materials such as graphite and carbon nanotubes. 

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... 

The temperature dependent formation and transformation of meso-structures in water-[bmim][BF4] mbctures has been investigated using nitroxide spin probes. The temperature dependence of the solution structure was monitored via a spin probe. Additionally the phase behaviour on cooling and reheating was probed by differential scanning calorimetry. Thermal hysteresis and memory effects were observed. EPR data before and after freezing revealed a transformation of the mesostructures, probably triggered by crystallization of water pools to ice. 

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 glass-tiansition tempeiatuiesfoi solution-polymeiized SBR as well as ESBR aie loutinely determined by nuclear magnetic resonance (nmr), differential thermal analysis (dta), or differential scanning calorimetry (dsc). 

The thermal glass-transition temperatures of poly(vinyl acetal)s can be determined by dynamic mechanical analysis, differential scanning calorimetry, and nmr techniques (31). The thermal glass-transition temperature of poly(vinyl acetal) resins prepared from aliphatic aldehydes can be estimated from empirical relationships such as equation 1 where OH and OAc are the weight percent of vinyl alcohol and vinyl acetate units and C is the number of carbons in the chain derived from the aldehyde. The symbols with subscripts are the corresponding values for a standard (s) resin with known parameters (32). The formula accurately predicts that resin T increases as vinyl alcohol content increases, and decreases as vinyl acetate content and aldehyde carbon chain length increases. 

What are the consequences What is the maximum pressure Vapor pressure of solvent as a function of temperature Gas evolution Differential Thermal Analysis (DTA) / Differential Scanning Calorimetry (DSC) Dewar flask experiments... 

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). 

Difl erential thermal analysis (DTA) and differential scanning calorimetry (DSC) are the other mainline thermal techniques. These are methods to identify temperatures at which specific heat changes suddenly or a latent heat is evolved or absorbed by the specimen. DTA is an early technique, invented by Le Chatelier in France in 1887 and improved at the turn of the century by Roberts-Austen (Section 4.2.2). A... 

Differential scanning calorimetry Differential thermal analysis Hot stage microscope... 

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. 

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