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

  • Hongfang Zhao
  • Paul Ki-souk Nam
  • Von L. Richards
  • Simon N. Lekakh
Article
  • 1 Downloads

Abstract

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 700 °C under air atmosphere while there was about 20% residue remaining at 800 °C under N2 atmosphere. The PU foam showed two Tgs at 56 and 140 °C. The EPS foam and SLA demonstrated single Tg at 106 and 55 °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.

Keywords

investment casting EPS polyurethane epoxy thermal degradation hydrogen cyanide 

Notes

Acknowledgements

The authors would like to thank the US Army Benét Laboratories for funding this research.

References

  1. 1.
    US 4655276, 1987Google Scholar
  2. 2.
    D. Kline, S. Lekakh, C. Mahimkar, V. Richards, presented in part at the Technical and Operating Conference, Chicago, IL (2009)Google Scholar
  3. 3.
    C.M. Cheah, C.K. Chua, C.W. Lee, C. Feng, K. Totong, Int. J. Adv. Manuf. Technol. 25, 308–320 (2005)CrossRefGoogle Scholar
  4. 4.
    Y. Norouzi, S. Rahmati, Y. Hojjat, Rapid Prototyp. J. 15, 255–263 (1995)CrossRefGoogle Scholar
  5. 5.
    D. Neece, Advanced Pattern Material for Investment Casting Applications (Cleveland Tool and Machine, Brookpark, OH, Department of Energy, Washington, DC, 2006)Google Scholar
  6. 6.
    K. Sumi, Y. Tsuchiya, J. Fire Flammabl. 4, 15–22 (1973)Google Scholar
  7. 7.
    A. Alajbeg, J. Anal. Appl. Pyrol. 10, 215–224 (1987)CrossRefGoogle Scholar
  8. 8.
    B.C. Levin, M. Paabo, M.L. Fultz, C.S. Bailey, Fire Mater. 9, 125–134 (1985)CrossRefGoogle Scholar
  9. 9.
    B.C. Levin, M. Paabo, J.L. Gurman, S.E. Harris, Fundam. Appl. Toxicol. 9, 236–250 (1987)CrossRefGoogle Scholar
  10. 10.
    F.M. Esposito, Y. Alarie, J. Fire Sci. 6, 195–242 (1988)CrossRefGoogle Scholar
  11. 11.
    K. Yamamoto, J. Combust. Toxicol. 4, 69–78 (1977)Google Scholar
  12. 12.
    R.A. Anderson, I. Thomson, W.A. Harland, Fire Mater. 3, 91–99 (1979)CrossRefGoogle Scholar
  13. 13.
    E. Dyer, R.E. Read, J. Org. Chem. 26, 4388–4394 (1961)CrossRefGoogle Scholar
  14. 14.
    E.G. Bligh, W.J. Dyer, Can. J. Biochem. Physiol. 37, 911–917 (1959)CrossRefGoogle Scholar
  15. 15.
    E. Dyer, G.E. Newborn, J. Am. Chem. Soc. 80, 5495–5498 (1958)CrossRefGoogle Scholar
  16. 16.
    M.P. Thorne, Can. J. Chem. 45, 2537–2546 (1967)CrossRefGoogle Scholar
  17. 17.
    M. Boutin, J. Lesage, C. Ostiguy, J. Pauluhn, M.J. Bertrand, J. Anal. Appl. Pyrol. 71, 791–802 (2004)CrossRefGoogle Scholar
  18. 18.
    W. Everhart, S. Lekakh, V. Richards, J. Smith, H. Li, K. Chandrashekhara, H. Zhao, P. Nam, presented in part at the Transactions of the American Foundry Society (2012)Google Scholar
  19. 19.
    H. Zhao, M. Xu, H. Li, W. Everhart, S. Lekakh, V. Richards, K. Chandrashekhara, P. Nam, presented in part at the Investment Casting Institute, Covington, KY (2011)Google Scholar
  20. 20.
    D.L. Beck, A.A. Hiltz, J.R. Knox, Polym. Eng. Sci. 3, 279–285 (1963)CrossRefGoogle Scholar
  21. 21.
    S. Gordon, B.J. McBride, NASA SP-273 (1971)Google Scholar

Copyright information

© American Foundry Society 2018

Authors and Affiliations

  • Hongfang Zhao
    • 1
  • Paul Ki-souk Nam
    • 1
  • Von L. Richards
    • 2
  • Simon N. Lekakh
    • 2
  1. 1.Department of ChemistryMissouri University of Science and TechnologyRollaUSA
  2. 2.Department of Materials Science and EngineeringMissouri University of Science and TechnologyRollaUSA

Personalised recommendations