Thermal Volatilisation Analysis TVA

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. 

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. 

Principles and Characteristics In thermal volatilisation analysis (TVA) the volatile products are passed from a heated sample in a continuously evacuated system 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 the pressure is recorded as the sample temperature is increased in a linear manner, a thermal volatilisation analysis (TVA) thermogram is obtained showing one or more peaks. The thermogram indicates the variation of rate of volatilisation of the sample with temperature. TVA is essentially a pyrolysis technique, which records the pressure of the volatile pyrolysates. The TVA trace is somewhat dependent on heating rate, as in case of TG, and should therefore be standardised. 

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. ... 

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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