Study of the thermal degradation of polyisobutylene binder for the production of titanium matrix composites via experiment and Reactive Molecular Dynamic simulations

Abstract

The purpose of the present investigation is to study the efficacy of using Polyisobutylene (PIB) as the binder for the production of titanium matrix composites via tape casting. Various experimental techniques were performed to study the decomposition products and kinetics of the debinding process. These include gas chromatography, mass spectrometry, thermogravimetry and Fourier Transform Infra-Red spectrometry. Product and kinetic analyses were performed on samples of the PIB and titanium powder/PIB tapes that were subjected to isothermal heating. Global kinetic parameters were calculated from the TG mass loss data and are compared to the kinetic parameters for monomer formation measured by FTIR. Unfortunately, these techniques can only provide information about the distribution of stable products that are formed during the debinding process, which is insufficient for the determination of optimal processing conditions. Computer simulations, based on Reactive Molecular Dynamics (RMD), were employed to obtain more detailed information about reactive intermediates and the mechanisms of the thermal degradation of the binder. In this paper, we compare the kinetic parameters and product distributions from the simulations to experimental values and advance a temperature dependent mechanism for the thermal decomposition of the PIB binder.