Prediction of the lifetime of nitrile-butadiene rubber by FT-IR.
A quantitative measurement method with FT-IR was proposed for a thermal degradation analysis of nitrile-butadiene rubber (NBR). An NBR film was prepared as a model sample on a barium fluoride (BaF2) crystal plate, which was subjected to a heat treatment. The absorbances of various functional groups were measured directly by FT-IR after thermal degradation at high temperatures. By measuring the absorbances, it was possible to readily determine quantitatively each of the functional groups after the degradation of NBR. By assuming that the NBR lifetime was the point at which the absorbance of a carbon-carbon double bond reaches 45% of that prior to thermal treatment, a method for predicting the lifetime of NBR heated below 150 degrees C was proposed, by using an Arrhenius plot of the heating time versus heating temperature.
The comparative kinetic analysis of non-isothermal degradation process of acrylonitrile–butadiene and ethylene–propylene–diene rubber compounds. Part I
Abstract The non-isothermal degradation processes of acrylonitrile–butadiene and ethylene–propylene–ethylidenenorbornene rubber compounds were investigated with thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG), using the different calculation procedures. It was found that the acrylonitrile–butadiene (NBR) and the ethylene–propylene–diene (EPDM) rubber degradations represent the complex processes, where there are conversion regions with a constant value of the apparent activation energy (Ea). It was established that the NBR and EPDM degradation under nitrogen atmosphere can be described by the one and a half order (n = 3/2) and the first order (n = 1) reaction kinetics, respectively. A linear dependence was observed between ln A and Ea at every heating rate, known as the artificial compensation effect (art-CE). It was found that the calculated differential conversion curves are in good agreement with the experimental ones, for each of the observed heating rates, thus confirming the correctness of the obtained reaction models for the NBR and EPDM degradation processes.
Modifications to a Commercial Infrared Emission Apparatus to Permit Quantitative Applications
Infrared (IR) emission spectroscopy is an ideal candidate for in situ process monitoring. Infrared spectra contain a wealth of information, and measurement of an IR emission spectrum requires only that a sufficient temperature difference exist between the radiating sample and the detector. A probe beam, such as required for absorbance or reflectance measurements, is not needed, and the sample need not be transparent. The lack of constraints on sample type and relatively simple instrumentation required to make infrared emission measurements are the major reasons that infrared emission spectroscopy has potential as a process-monitoring technique.