Thermal Decomposition Studies of EPS Foam, Polyurethane Foam, and Epoxy Resin (SLA) as Patterns for Investment Casting; Analysis of Hydrogen Cyanide (HCN) from Thermal Degradation of Polyurethane Foam
Thermal and chemical characteristics of three different polymer pattern materials for investment casting were investigated: expandable polystyrene foam (EPS), polyurethane (PU) foam at three densities, and epoxy resin (SLA). Thermal degradation behaviors and glass transition temperatures (Tg) of polymers were examined by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively. The TGA results indicated that both EPS foam and SLA were degraded more readily than the PU foam, which was decomposed completely at 700Â °C under air atmosphere while there was about 20% residue remaining at 800Â °C under N2 atmosphere. The PU foam showed two Tgs at 56 and 140Â °C. The EPS foam and SLA demonstrated single Tg at 106 and 55Â °C, respectively. The generation of toxic gas, hydrogen cyanide (HCN) from thermal degradation of the PU foam was examined by a laboratory-built heating system. The HCN level depended on decomposition conditions, higher oxidant level, and longer residence time in the hot zone of furnace could reduce the HCN level.
H. Zhao et al., "Thermal Decomposition Studies of EPS Foam, Polyurethane Foam, and Epoxy Resin (SLA) as Patterns for Investment Casting; Analysis of Hydrogen Cyanide (HCN) from Thermal Degradation of Polyurethane Foam," International Journal of Metalcasting, vol. 13, no. 1, pp. 18-25, Springer International Publishing, Jan 2019.
The definitive version is available at https://doi.org/10.1007/s40962-018-0240-5
Materials Science and Engineering
Keywords and Phrases
Epoxy; EPS; Hydrogen Cyanide; Investment Casting; Polyurethane; Thermal Degradation
International Standard Serial Number (ISSN)
Article - Journal
© 2019 American Foundry Society, All rights reserved.
01 Jan 2019