Differential scanning calorimetry defined

Most hydrocarbon resins are composed of a mixture of monomers and are rather difficult to hiUy characterize on a molecular level. The characteristics of resins are typically defined by physical properties such as softening point, color, molecular weight, melt viscosity, and solubiHty parameter. These properties predict performance characteristics and are essential in designing resins for specific appHcations. Actual characterization techniques used to define the broad molecular properties of hydrocarbon resins are Fourier transform infrared spectroscopy (ftir), nuclear magnetic resonance spectroscopy (nmr), and differential scanning calorimetry (dsc). 

Define thermal analysis, differential thermal analysis, differential scanning calorimetry, and ther-... 

The liquid fraction sensitivity is an important parameter for the determination of the semi-solid forming capability. It is defined as the rate of change of the liquid fraction in the alloy with temperature and is related to the relative slopes, in the phase diagram, of the liquidus and solidus curves. It may be determined by differential scanning calorimetry or predicted by thermodynamic modelling. Examples related to various Al alloys have been reported by Maciel Camacho et al. (2003), Dong (2003). See also several papers in Chiarmetta and Rosso (2000). 

Differential scanning calorimetry (DSC). The DSC analyses were carried out using a Perkin-Elmer DSC-7 and a DuPont 910DSC. Tg was defined as the midpoint of the change in heat capacity occurring over the transition. The samples were first scanned to 95°C, thereafter cooled and recorded a second time. The Tg was determined from the second run. The measurements were carried out under an atmosphere of dry nitrogen at a heating rate of 10°C/min. 

Chromophores must be thermally robust enough to withstand temperatures encountered in electric field poling and subsequent processing of chromophore/polymer materials. Chromophore decomposition temperatures can be assessed by techniques such as thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). TGA and DSC measurements on neat chromophore samples in air will tend to yield decomposition temperatures lower than those for the same chromophores in hardened polymer lattices. Typically, to be useful for development of device quality materials, a chromophore must exhibit thermal stability of 250 °C or higher (with thermal stability defined as... 

Figure 28. (ia) Normalized sample capacitance versus temperature at 1.2 MHz for a film thickness of 310 nm the dotted lines serve as a guide for the reader, (b) The corresponding first and second numerical derivatives with respect to the temperature T. The Tg is defined as the maximum of the second derivative, (c) the normalized heat flow versus temperature, as measured by Differential Scanning Calorimetry. Inset, part a The second derivative of the Cnarm. versus temperature dependence for a film thickness of 310nm and 17 nm. 

Infrared spectra (IR) were taken on a Nicolet 7199 FT-IR. Thermal analyses were obtained on a DuPont 1090 thermal analyzer. Thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) were performed at lO C/min. heating rates under N2. Reduced viscosity measurements (4) were made at 40-C in OC Ubbelohde viscometers. Values reported are the average of at least two measurements, which were within 0.2% of each other. Reduced viscosity is defined as follows ... 

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