Measurement of the oxidative stability of polyethylene by differential thermal analysis

An evaluation has been made of the experimental features critical to the evaluation of the oxidative stability of polyethylene using constant temperature DTA, with particular reference to the control and measurement of the sample temperature.     

Development and applications of sample controlled thermomicroscopy

Sample controlled thermal analysis techniques such as constant rate transformation analysis or stepwise isothermal analysis, where the transformation rate of the sample itself is used to control the experiment, are becoming increasingly important [1]. The measurements are normally carried out using changes in the sample mass, sample dimensions or in the evolved gas, as the property used to control the experiment, and enable reactions to be studied in greater detail than is possible using linear heating techniques. A new approach is described here where a thermomicroscopy system has been developed to enable the intensity of the light reflected or transmitted by the sample to be used as the controlling signal [2]. This revised version was published online in July 2006 with corrections to the Cover Date.     

The European Symposium on Thermal Analysis and Calorimetry

The first European Symposium on Thermal Analysis and Calorimetry (ESTAC) was held in Salford, UK in 1976. On the occasion of the tenth ESTAC in Rotterdam, this is article provides an overview of the history, aims and philosophy of ESTAC.     

Calibration of differential scanning calorimeters: A comparison between indium and diphenylacetic acid

The close proximity in melting temperature of the LGC Limited DSC standards indium and diphenylacetic acid, has enabled a direct assessment to be made of any differences resulting from the use of a metal or an organic compound in the calibration of DSC equipment. Following calibration with indium, the equilibrium fusion temperatures for diphenylacetic acid, were determined by both the stepwise heating and extrapolation to zero heating rate methods. The results were in excellent agreement with the certificate values and established that indium may be used as a calibrant when making accurate DSC measurements on organic materials in the same temperature range and that it has the advantage that it is non-volatile and can be used a number of times without significant change. Similar agreement was obtained in the measurement of the enthalpy of fusion, although the larger heat capacity change on fusion of diphenylacetic acid resulted in a greater uncertainty than with indium.     

Development and applications of a preparative scale sample controlled thermogravimetric system

Journal of Thermal Analysis and Calorimetry -     

A new high sensitivity thermobalance

A new thermobalance is described which gives a direct plot of percentage weight loss versus sample temperature, without the need for replotting the results. The unit operates over the range ambient to 1000°C and features a miniature water-cooled furnace in conjunction with an electronic microbalance, giving sensitivities of 1–250 mg for full scale deflection on a potentiometric recorder. Heating rates of 1–100°C/minute are available and the furnace will cool from 1000°C to 50°C in less than four minutes. Typical applications of the unit are illustrated by reference to a number of inorganic and polymer systems.     

Applications of a new quadrupole mass spectrometer system for simultaneous thermal analysis-evolved gas analysis

A recently-developed quadrupole mass spectrometer system specifically designed for thermal analysis studies, has been linked to a thermobalance and a simultaneous TG-DTA unit, for evolved gas analysis. The performance and applicability of the system is illustrated by examples from four fields of study     

A study of the effect of purity on the use of nickel as a temperature standard for thermomagnetometry

Samples of nickel, varying by four orders of magnitude in their purity, were studied by thermomagnetometry (TM), to determine if the extrapolated end point (T _C ) changes.T _C is virtually identical for the 99.99 and 99.999% samples. Samples of less purity did show changes. Simultaneous DTA/TM can accurately defineT _C by comparing with the melting points of pure metals determined simultaneously. The melting points of lead and zinc bracket theT _C for nickel. They were added to the sample pan prior to TM of nickel. Experiments were performed at heating rates in the range from 1 to 20 deg·min^?1. It serves as a pilot study for the ICTAC Committee for Standardization to more accurately define the recommended values ofT _C .     

In Memoriam

In memoriam Michael John Richardson.