Perkin-Elmer thermobalance

The TGA system was a Perkin-Elmer TGS-2 thermobalance with System 4 controller. Sample mass was 2 to 4 mgs with a N2 flow of 30 cc/min. Samples were initially held at 110°C for 10 minutes to remove moisture and residual air, then heated at a rate of 150°C/min to the desired temperature set by the controller. TGA data from the initial four minutes once the target pyrolysis temperature was reached was not used to calculate rate constants in order to avoid temperature lag complications. Reaction temperature remained steady and was within 2°C of the desired temperature. The actual observed pyrolysis temperature was used to calculate activation parameters. The dimensionless "weight/mass" Me was calculated using Equation 1. Instead of calculating Mr by extrapolation of the isothermal plot to infinity, Mr was determined by heating each sample/additive to 550°C under N2. This method was used because cellulose TGA rates have been shown to follow Arrhenius plots (4,8,10-12,15,16,19,23,26,31). Thus, Mr at infinity should be the same regardless of the isothermal pyrolysis temperature. A few duplicate runs were made to insure that the results were reproducible and not affected by sample size and/or mass. The Me values were calculated at 4-minute intervals to give 14 data points per run. These values were then used to... 

The thermogram of bromocriptine mesilate, carried out on a Perkin Elmer TGS-1 thermobalance, is given in fig. 9. 

Weight Losses. Weight losses were determined on a Perkin-Elmer model TGS-2 thermobalance, using either nitrogen or air as sweeping gas. 

X-ray powder diffraction patterns were obtained on oriented film specimens [7] (2 to 45° 2 , Philips PW 1120, monochromatized CuKa radiation, continuous peak registration). BET surface area and the pore volume distribution were determined from Nj adsorption-desorption isotherms at 77 K (degassing at 393 K, lO" mbar, 5h Sorptomatic 1900, Carlo Erba Instruments). The IR-spectra were recorded on KBr wafers [4] with a Specord 80M spectrometer. The XPS (X-ray photoelectron spectroscopy) spectra were obtained with VG ESCALAB 200 MKII spectrometer equipped with a twin anode AIKa source (1486 eV). The thermogravimetric (TGA) analyses were carried out with a Setaram TG 85 thermobalance at a heating rate of 6 K min in a helium flow of 30 ml min . The chromium content of the samples was determined by EPMA (JEOL 840 scanning electron microscope) with energy dispersive spectrometer (EDS, Tracer Northern) and by AAS (atomic absorption spectroscopy, Perkin Elmer 3030) analyses. 

Perkin-Elmer Model TGS-1 Thermobalance Brochure, Perkin-Elmer Co.. Norwalk, C. 

The hangdown tube and furnace assembly used by Etter and Smith (47) is illustrated in Figure 3.31. A small platinum resistance heater located inside a relatively short quartz sample tube is used as the furnace. The temperature-sensing thermocouple is located inside the furnace chamber with entry into the chamber from the bottom. This design is similar to that of the Perkin-Elmer thermobalance. 

Elemental composition of the calcined AIPO4 was determined by SEM-EDX (JEOL-JSM 6300, 20 kV). TG-DTA measurements were performed in flowing Ar (293-1173 K, 10 K min ) using a Setaram thermobalance Setsys-12. XRD patterns (CuK radiation) were developed in a Siemens D-5000 diffractometer. FT-Raman spectra were taken from compacted samples at 3600-200 cm (resolution 0.2 cm ), using a Perkin-Elmer System 2000 spectrometer. XPS were recorded on a Leybold-Heraeus LHS-10 spectrometer (at 10 Torr) using Al Ka radiation and a pass energy constant of 50 eV. A1, P and MAS-NMR spectra were recorded on a Bruker ACP-400 spectrometer. DRIFT spectra (4000-400 cm resolution 8 cm 256 scans) were recorded on a Bomem MB-100 FT-IR instrument equipped with an environmental chamber placed in a DRIFT attachment. DRIFT spectra were recorded for calcined materials (200 mesh size and diluted to 15 wt% KBr) previously vacuum-dried at 400 K for 24... 

IR spectra were recorded using the KBr disk technique and a Perkin-Elmer 1750 FTIR spectrometer. Surface area and pore volume were determined on a C. Erba Sorptomatic model 1700 apparatus, by means of Nj adsorption. Thermogravimetric (TO) analyses were carried out using a Perkin-Elmer TGS-2 thermobalance with a He-flow of 3dm /h and a heating rate of 600K/h. 

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