Incorporation of PVP into PEG/PMMA based binder system to minimize void nucleation

In spite of its great potential, the polyethylene glycol (PEG) and polymethyl methacrylate (PMMA) binder system was found susceptible to void nucleation, as the rigid PMMA chains hinder PEG volumetric shrinkage upon cooling. We previously reported that this void formation could be minimized by either using a higher cooling rate or by incorporating a crystallization inhibitor in the binder system. In this paper, efforts have been made to increase the workability of this binder system for conventional metal injection molding (MIM) by adding the crystallization inhibitor, polyvinylpyrrolidone (PVP). Differential scanning calorimetry (DSC), rheological property measurements, solvent and thermal debinding behavior, and fracture surface analysis of the molded samples were performed. Incorporation of PVP into the PEG/PMMA binder system is successful in that high quality void-free MIM components have been produced while maintaining the clean nature of the PEG/PMMA binder system.