Nowadays having the maximum amount of information of plastic material is a priority when solving different problems regarding the processing, the selection of materials and the quality of the raw material and the final product, the development of new compounds or products, etc. That information is sometimes difficult to obtain quickly and easily and requires using different analytical techniques used separately and with laborious sample preparations and that provide us with information on a very specific aspect of the product or material analysed. For that reason, combined techniques are very useful as they allow the coupling of different instruments that, on the same sample, obtain different types of information at the same time. This combination becomes a very powerful tool when comparing products and materials.
For that reason, a transfer line has been installed recently at AIMPLAS’ Chemical Characterization Laboratory, which makes possible to connect thermal analysis equipment, specifically a thermogravimetric analyser (TGA), with a Fourier Transform Infrared (FT-IR) spectrophotometer.
With this transfer line it is possible to obtain the infrared spectrum, and therefore information on the composition, the volatile substances and degradation products that are produced during a temperature scan of a plastic sample analysed by TGA.
The transfer line makes all the substances, in the gas phase, generated in the thermogravimetric analysis to reach the spectrometer, which will perform spectra in a programmed and fast way, being able to establish a chemical profile of all the substances that are coming out of the thermogravimetric analyser. This way, different degradations or loss of volatiles, which in the TGA are represented by weight losses, and which occur at intervals in time, will be monitored online in the spectrophotometer thanks to the acquisition and obtaining of infrared spectra that change over time as the chemical composition of the substances produced during thermogravimetric analysis changes.
The possibility of knowing chemically what is going on during the thermogravimetric scanning due to the union of these analytical techniques opens up a vast world of possibilities in the analysis of plastic samples.
César Gadea Tomás
Chemical Characterization Laboratory