Thermal Analysis System

Play back and plot data from a previous experiment, even if collected from a different module. 

In addition, the RS-232 port can be used simultaneously during data collection and analysis to transmit data to an external computer and to receive commands from the computer to provide automated setup of instrument conditions. 

A comprehensive library of module specific software programs are available, including  

---

An Automated Thermal Analysis System for Reaction Kinetics," A.F. Kah, M.E. Koehler, T.H. Grentzer, T.F. Niemann, and T. Provder, Computer Applications... 

Measurements of differential scanning calorimetry (DSC) were obtained on a TA Instruments 2910 thermal analysis system (Fig. 2). Samples of approximately 1-2 mg were accurately weighed into an aluminum DSC pan, and covered with an aluminum lid that was crimped in place. The samples were then heated over the range of 20-140 °C, at a heating rate of 10 °C/min. Valproic acid was found to boil at 227 °C. 

Dynamic mechanical anlaysis (DMA) measurements were done on a Rheometrics RDS-7700 rheometer in torsional rectangular geometry mode using 60 x 12 x 3 mm samples at 0.05% strain and 1 Hz. Differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and thermogravimetric analysis (TGA) were performed on a Perkin-Elmer 7000 thermal analysis system. 

Characterization. IR spectra of the samples were recorded on Nicolit AVATAR360 spectrometer. The TEM images were obtained on Hitachi H-8100IV electron microscope. TGA and DTA analyses were carried out in Du pont 9900 Thermal Analysis System. X-ray diffraction (XRD) measurement was conducted on a Siemens D5005 diffractometer using Cu Ka radiation (X = 1.54 °A). 

Kah, A. F. Koehler, M. E. Grentzer, T. H. Niemann, T. F. Provder, T. "An Automated Thermal Analysis System for Reaction Kinetics" in "Computer Applications in Applied Polymer Science" Provder, T., Ed. ACS SYMPOSIUM SERIES No. 197, American Chemical Society Washington, D.C., 1982 pp. 197-311. 

Resin Analysis. Thermal analysis of the BCB resin systems included Differential Scanning Calorisietry (DSC) using a DuPont 010 cell and Thermal Gravimetric Analysis (TGA) run on a DuPont 951 TGA, the entire thermal analysis system run using an Omnitherm model 35053... 

Differential scanning calorimetry is primarily used to determine changes in proteins as a function of temperature. The instrument used is a thermal analysis system, for example a Mettler DSC model 821e. The instrument coupled with a computer can quickly provide a thermal analysis of the protein solution and a control solution (no protein). The instrument contains two pans with separate heaters underneath each pan, one for the protein solution and one for the control solution that contains no protein. Each pan is heated at a predetermined equal rate. The pan with the protein will take more heat to keep the temperature of this pan increasing at the same rate of the control pan. The DSC instrument determines the amount of heat (energy) the sample pan heater has to put out to keep the rates equal. The computer graphs the temperature as a function of the difference in heat output from both pans. Through a series of equations, the heat capacity (Cp) can be determined (Freire 1995). 

Three to 4 mg of extracted biopolymers was encapsulated in aluminum pans for the measurements. Each sample was first annealed at 200°C for 3 min. The melting point was determined using a Mettler DSC 30 Thermal Analysis System. Dry nitrogen was used as the flow gas with a flow rate of 30 mL/min, calibrated with indium and mercury. 

An Automated Thermal Analysis System for Reaction Kinetics... 

We have used in this work, the Mettler TA2000B thermal analysis system and the supplied Kinetic and Applied Kinetic Programs. This instrument and associated software is capable of analyzing on-line the nth-order equation (1.1). 

Instrumental. The Mettler TA2000B thermal analysis system is equipped with an interface system, and Hewlett-Packard 9815 desk top calculator and 7225 plotter. Samples, weighing 5-10 mg, sealed in aluminum pans and under a nitrogen blanket, were heated in the calorimeter at a rate of 10 deg/min from -35 or 10 deg C to 180 deg C respectively, for specific heat and kinetic scans. Specific heat measurements were calibrated with alumina to an accuracy of 3%. Temperatures and enthalpies were calibrated with an Indium sample. The accuracies were .02 deg C and 2% (Indium 28.5 J/g), respectively. 

Advanced Thermal Analysis System (ATHAS) Polymer Heat Capacity Data Bank... 

Thermal analysis systems require calibration both in terms of temperature and the physical property being measured, so as to detect and eliminate the inherent systematic errors associated with the analysis. Thus, for example, TGA systems require both temperature... 

Thermal analysis systems require calibration prior to routine use. In TGA, calibration for mass is carried out by calibrating the microbalance using a set of standard weights, as for any balance system. Temperature calibration is effected by measuring the Curie point temperatures of a suite of International Confederation for Thermal Analysis and Calorimetry (ICTAC) Certified Reference Materials, which have well-defined Curie points. ... 

Such a differential heating program leads to increased sensitivity and resolution in TGA but also to a much increased time-frame for the analysis. Dynamic rate TG appears to have addressed both of these features and hence has much potential as a high resolution/ rapid thermal analysis system, which, unlike SCTA, can be applied for rapid and reproducible thermal analysis of a wide range of complex materials. Finally, modulated temperature thermogravimetrie analysis has enhanced potential for the kinetic analysis of thermal decomposition reactions over conventional TGA because of its greater resolution of thermal events. 

Figure 16-27. DSC thermograms of Ooct-OPV5 (left) and Ooct-OPV5-CN (right), recorded on a Perkin Elmer 7 series thermal analysis system at heating and cooling rates of 10 °C min...

As previously noted, siloxanes undergo extensive rearrangements at temperatures in excess of 35O C, often forming cyclic products. Because of the significant mechanical, chemical, and electrical properties offered by siloxanes and modified siloxanes, great effort is still directed towards increasing the use temperature of such products. This work is closely associated with sophisticated thermal analysis systems and is often aimed at preventing the depolymerization (reversion) reaction. 

The Derivatograph, which was first described by Paulik et al. (35) in 1958, is a multifunction thermal analysis system which can record the TG, DTG, DTA, and T curves of a sample on a single chart. By means of accessory attachments, the TD (thermal dilation) and DTD (derivative of TD) (5) curves may be recorded as well as the evolved gas curves (see Chapter 8). 

The Mettler TMA 40 thermomechanical analyzer is illustrated in Figure 11.3. A measuring sensor applies a user-definable force to the sample of -0.05-0.5 N. The position of the sensor is continuously monitored by a LVDT. TMA measurements can be made in the temperature range -100-1000 C. This module is part of the Mettler TA 3000 thermal analysis system. 

Dunn et al. (58) interfaced a DEC PDP 11-10 computer to a DuPont Model 990 thermal analysis system. The BCD-binary converter used a cascade of 15 6 bit BCD-binary ROMs to convert the 4.5-digit BCD output of the Hewlett-Packard Model HP 3430D digital voltmeter to bit binary for input to the DEC DR-11C general input-output device. All software was written in FOCAL, under the RT-11 operating system. 

Due to the rapid changing technology in microcomputers and microprocessors, data and control systems have evolved rapidly a life time of 3-4 years is about the maximum for such a system. Thus, only the most current computer system will be described here for a particular type of thermal analysis system. No attempt will be made to give details on the software programs in use these can be obtained from the commercial vendor of the system, if desired. Almost all the commercially available thermal analysis instrumentation employs a microprocessor for operating system control or a microcomputer for data processing. Either a proprietary or a commercially available microcomputer is employed to process the experimental data into conventional thermal analysis plots or to perform more sophisticated kinetics or purity determination calculations. 

---