Experimental and Molecular Dynamic Studies of Thermal Decomposition of a Polyisobutylene Binder
C S. Jee, Z X. Guo, S I. Stoliarov, Marc R. Nyden
Polymer debinding is involved in many powder metallurgy processes, where clean removal of the binder is essential to ensure a sound product. This investigation focuses on polyisobutylene (PIB) as a fugitive binder, with titanium powder as a model system. The products and the kinetics of debinding were evaluated by thermogravimetry (TG) and Fourier Transform InfraRed (FTIR) analyses. Global kinetic parameters were estimated from the TG data and compared with the kinetic parameters for monomer formation from the FTIR. The monomer isobutylene was identified to be the most abundant decomposed species, while other species also existed, e.g., 2,2,4-trimethyl pentane and oligomers of PIB. Computer simulations were carried out using a Reactive Molecular Dynamics (RMD) code, to clarify further the decomposition mechanisms, reaction paths and the possible effect of titanium on decomposition. The results from the simulations agree well with experimental findings, confirming the predictive power of the simulation method.