Thermal volatilisation analysis

In this technique, in a continuously evacuated system the volatile products are passed from a heated sample to the cold surface of a trap some distance away. A small pressure develops which varies with the rate of volatilisation of the sample. If this pressure is recorded as the sample temperature is increased in a linear manner, a thermal volatilisation analysis thermogram showing one or more peaks is produced. The trace obtained is somewhat dependent on heating rate, which therefore should be standardised. 

The technique has been applied to a range of polymers including polystyrene [2, 3], styrene-butadiene copolymers [2], polyvinylchloride [2], polyisobutene, butyl rubber and chlorobutyl rubber, and poly-a-methylstyrene [2]. 

McNeill, Journal of Polymer Science, Part A-1 Polymer Chemistry Edition, 1966, 4,10, 2479. 

Mehmet and R.S. Kocht, Journal of Applied Polymer Science, 1976,20, 7, 1955. 

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The applications of simultaneous TG-FTIR to elastomeric materials have been reviewed in the past. Manley [32] has described thermal methods of analysis of rubbers and plastics, including TGA, DTA, DSC, TMA, Thermal volatilisation analysis (TVA), TG-FTIR and TG-MS and has indicated vulcanisation as an important application. Carangelo and coworkers [31] have reviewed the applications of the combination of TG and evolved gas analysis by FTIR. The authors report TG-FTIR analysis of evolved products (C02, NH3, CHjCOOH and olefins) from a polyethylene with rubber additive. The TG-FTIR system performs quantitative measurements, and preserves and monitors very high molecular weight condensibles. The technique has proven useful for many applications (Table 1.6). Mittleman and co-workers [30] have addressed the role of TG-FTIR in the determination of polymer degradation pathways. 

Thermoplastic polyester elastomers Tripropylene glycol diacrylate Triphenyl phosphate Thermoplastic polyurethane Trimethylolpropanetrimethacrylate Thermal volatilisation analysis Transmitter signal... 

During an investigation of the thermal degradation of poly(vinylchloride - vinylacetate) blends, McNeill (14) observed acetyl chloride in the degradation products. We investigated this aspect by FTIR-EGA and found that the amount of acetyl chloride in the effluent decreased with increased residence time in the hot zone. This suggested that acetyl chloride is a primary decomposition product, rather than a product of reaction between HCl and acetic acid from pyrolysis of the copolymer. McNeill s work was performed by thermal volatilisation analysis and did not provide on-the-fly identification of the pyrolysis products. 

Turnbull L, Liggat JJ, MacDonald WA. Thermal degradation chemistry of poly(ethylene naph-thalate) - a study by thermal volatilisation analysis. PolymDegrad Stab 2013 98(11) 2244-58. 

In 1991, McNeill and Bounekhel [38] studied the thermal degradation of PET using thermal volatilisation analysis (TVA), and subsequently made rather controversial assertions based on the results. 

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). 

Table 9.2 Thermal measurement possible with commercial analysers (excluding evolved gas analysis and thermal volatilisation analysis) ...

Thermal scanning microscopy Temperature-time profile Time/temperature resolved pyrolysis mass spectrometry Thermal ultraviolet Thermal volatilisation analysis Thermal wave infrared imaging Transmission X-ray microscopy Total-reflection X-ray fluorescence (c/r. TRXRF) Ultrasonic force microscopy Ultraviolet photoelectron spectroscopy Ultrasound... 

Libiszowski and co-workers [9] used TCA and thermal volatilisation analysis to investigate the thermal stability of a-ester (o-hydroxy terminated poly-L-lactides (PLA) i.e., [C HjOC(0)-PLA-OH] and its esterified counterpart [C H 0C(0)-PLA-OCfOlCHfC HjlC Hj]. Thermogravimetric measurements versus number average... 

Thermal volatilisation analysis (TVA) is a common method invented in the early 1970s that allows examination of the volatile products of degradation and gives the rate of volatilisation versus temperature (or time), as shown in Figure 3 for poly(isoprenyl acetate) (PIPA) [a.l5] 687290. ... 

Applied Spectroscopy 53, No.ll, Nov.1999, p.1403-11 THERMAL VOLATILISATION ANALYSIS A VERSATILE PLATFORM FOR SPECTROSCOPIC INVESTIGATION OF POLYMER DEGRADATION PROCESSES Guo X Huang B Dyakonov T Chen Y Padron L Vickstrom T Kuhn J Hodkiewicz J Stevenson W T K Wichita,State University Harrick Scientific Co. Oklahoma State University Koch Industries Inc. ATI Instruments... 

Thermal volatilisation analysis (TVA) and sub-ambient thermal volatilisation analysis (SATVA) techniques are described. In addition to rate profiling of the volatile product flux of thermal degradation under high-vacuum conditions through measurement of pressure in the vacuum line as a function of sample temperature, the TVA technique is shown to afford a convenient method for an on the basis of volatility under high-vacuum conditions, of product fractions of thermal degradation for subsequent spectroscopic analysis. The capacity and flexibility of TVA as a platform for these analyses are illustrated in a case study format by degrading poly(bisphenol A, 2-... 

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