Investment casting pattern material based on paraffin wax fortified with EVA and filled with PMMA

ABSTRACT Paraffin wax‐based compounds are utilized as investment casting pattern materials. This study considered the effect of composition variations on the properties of paraffin wax‐poly(ethylene‐co‐vinyl acetate) (EVA) blends filled with poly(methyl methacrylate) (PMMA) microbeads. The EVA addition significantly improved mechanical properties while the PMMA improved the needle penetration hardness. Both polymers increased the melt viscosity of the wax composition. Thermal gravimetric analysis of the pyrolysis behavior showed that the compounds volatilize readily with virtually no residue remaining above 500 °C. The 40/20/40 wax/EVA/PMMA composition offers a balanced property profile with the bending stress approaching 6 MPa, the bending strain at break exceeding 4%, and a melt viscosity of about 12 Pa s at 90 °C. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48774.