Iranian Polymer Journal

, Volume 22, Issue 6, pp 417–428 | Cite as

Open-celled microcellular foaming and the formation of cellular structure by a theoretical pattern in polystyrene

  • Mohammadsaeid EnayatiEmail author
  • Mohammad Hossein Navid FamiliEmail author
  • Hamed Janani
Original Paper


An open-celled structure was produced using polystyrene and supercritical carbon dioxide in a novel batch process. The required processing conditions to achieve open-celled structures were predicted by a theoretical model and confirmed by the experimental data. The theoretical model predicts that at least a saturation pressure of 130 bar and a foaming time between 9 and 58 s are required for this system to produce an open-celled structure. The foaming temperature range has been selected to be higher than the polymer glass transition temperature yet not higher than a temperature limit where the gas starts leaving the system. The experimental results in the batch foaming process verified the model substantially. The SEM pictures showed the presence of pores between the cells, and the mercury porosimetry test results verified the overall open-celled structure. Experimental results also showed that by increasing the saturation pressure and the foaming temperature, there was a drop in the time required for open-celled structure formation. At saturation pressure of 130 bar, foaming temperature of 150 °C and a foaming time of 60 s, open-celled microcellular polystyrene foams were obtained using supercritical CO2 in the batch process. Based on the results, a schematic diagram, depicting the process of foam structure formation from nucleation to bubble coalescence and gas escape from polymer, was proposed. Theoretical calculations showed that by increasing foaming time, cell size was increased and cell density was reduced and the experimental results verified this prediction.


Microcellular foam Open-celled structure Open-celled model Processing parameters Bubble coalescence 



The authors wish to thank Tarbiat Modares University due to financial and logistics supports.


  1. 1.
    Lee ST, Ramesh NS (2004) Polymeric foams: mechanisms and materials. CRC, Boca Raton 1CrossRefGoogle Scholar
  2. 2.
    Martini JE, Waldman FA, Suh NP (1982) The production and analysis of microcellular thermoplastic foam. ANTEC, 82 SPE Tech Pap 28:674–676Google Scholar
  3. 3.
    Martini JE (1981) The production and analysis of microcellular foam. MSc Thesis, Massachusetts Institute of TechnologyGoogle Scholar
  4. 4.
    Martini JE, Suh NP, Waldman FA (1984) Microcellular closed cell foams and their method of manufacture. US Patent 4(473):665Google Scholar
  5. 5.
    Xiangmin Han ME (2003) Continuous production of microcellular foams. PhD Thesis, the Ohio State UniversityGoogle Scholar
  6. 6.
    Holl MR (1995) Dynamic analysis measurement and control of cell growth in solid state polymeric foams. PhD Thesis, University of WashingtonGoogle Scholar
  7. 7.
    Faruk O, Bledzki KA, Matuana ML (2007) Microcellular foamed wood-plastic composites by different processes: a review. Macromol Mater Eng 292:113–127CrossRefGoogle Scholar
  8. 8.
    Kumar V (2005) Phenomenology of bubble nucleation in the solid-state nitrogen-polystyrene system. Colloid Surf A 263:336–340CrossRefGoogle Scholar
  9. 9.
    Krause B (2001) Polymer nanofoams. PhD Thesis, University of TwenteGoogle Scholar
  10. 10.
    Reignier J, Huneault MA (2006) Preparation of interconnected poly(ε-caprolactone) porous scaffolds by a combination of polymer and salt particulate leaching. Polymer 47:4703–4717CrossRefGoogle Scholar
  11. 11.
    Zhou C, Ma L, Li W, Yao D (2011) Fabrication of tissue engineering scaffolds through solid-state foaming of immiscible polymer blends. Biofabrication 3:045003CrossRefGoogle Scholar
  12. 12.
    Wang X, Li W, Kumar V (2009) Creating open-celled solid-state foams using ultrasound. J Cell Plast 45:353–369CrossRefGoogle Scholar
  13. 13.
    Li W, Wang H, Kumar V, Matula T (2012) Method of selective foaming for porous polymeric material. US Patent 201220091632Google Scholar
  14. 14.
    Kim DW, Hwang SS, Hong SM, Yoo HO, Hong SP (2001) Optimization of foaming process using triblock polyimides with thermally liable blocks. Polymer 42:83–92CrossRefGoogle Scholar
  15. 15.
    Baker RW (2000) Membrane technology and application. McGrow Hill, New York 3Google Scholar
  16. 16.
    Tate D (1994) Continuous production of microcellular foams. MSc Thesis, Massachusetts Institute of TechnologyGoogle Scholar
  17. 17.
    Huang Q, Seibig B, Paul D (1999) Polycarbonate hollow fiber membranes by melt extrusion. J Membr Sci 161:287–291CrossRefGoogle Scholar
  18. 18.
    Rodeheaver BA, Colton JS (2001) Open-celled microcellular thermoplastic foam. Polym Eng Sci 41:380–400CrossRefGoogle Scholar
  19. 19.
    Krause B, Boerrigter ME, van der Vegt NFA, Strathmann H, Wessling M (2001) Novel open-celled polysulfone morphologies produced with trace concentrations of solvents as pore opener. J Membr Sci 187:181–192CrossRefGoogle Scholar
  20. 20.
    Krause B, Münüklü P, van der Vegt NFA, Wessling M, Sijbesma HP (2001) Bicontinuous nanoporous polymers by carbon dioxide foaming. Macromolecules 34:8792–8801CrossRefGoogle Scholar
  21. 21.
    Park CB, Padareva V, Lee PC, Naguib HE (2005) Extruded open-celled LDPE- based foams using non-homogeneous melt structure. J Polym Eng 25:239–260CrossRefGoogle Scholar
  22. 22.
    Lee PC, Wang J, Park CB (2006) Extruded open-celled foams using two semicrystalline polymers with different crystallization temperatures. J Appl Polym Sci 102:3376–3384CrossRefGoogle Scholar
  23. 23.
    Huang Q, Seibig B, Paul D (2000) Melt extruded open-cell microcellular foams for membrane separation: processing and cell morphology. J Cell Plast 36:112–125CrossRefGoogle Scholar
  24. 24.
    Janani H, Famili MHN (2010) Investigation of a strategy for well controlled inducement of microcellular and nanocellular morphologies in polymers. Polym Eng Sci 50:1558–1570CrossRefGoogle Scholar
  25. 25.
    Colton JS, Suh NP (1987) Nucleation of microcellular foam: theory and practice. Polym Eng Sci 27:493–499CrossRefGoogle Scholar
  26. 26.
    Park HS (2007) Surface tension measurement of polystyrene in supercritical fluids. PhD Thesis, University of WaterlooGoogle Scholar
  27. 27.
    Matuana LM, Park CB, Balatinecz J (1997) Processing and cell morphology relationships for microcellular foamed PVC/wood-fiber composites. J Polym Eng Sci 37:1137–1147CrossRefGoogle Scholar
  28. 28.
    Famili MHN, Janani H, Enayati MS (2011) Foaming of a polymer-nanoparticle system: effect of the particle properties. J Appl Polym Sci 119:2847–2856CrossRefGoogle Scholar
  29. 29.
    Kumar V, Suh N (1990) A processing of making microcellular thermoplastic parts. Polym Eng Sci 30:1323–1329CrossRefGoogle Scholar
  30. 30.
    Krause B, Mettinkhof R, van der Vegt NFA, Wessling M (2001) Microcellular foaming of amorphous high-Tg polymers using carbon dioxide. Macromolecules 34:874–884CrossRefGoogle Scholar
  31. 31.
    Park CB, Behravesh AH, Venter RD (1998) Low density microcellular foam processing extrusion using CO2. Polym Eng Sci 38:1812–1823CrossRefGoogle Scholar
  32. 32.
    Kumar V, Weller J (1994) Production of microcellular polycarbonate using carbon dioxide for bubble nucleation. J Eng Ind 116:413–420CrossRefGoogle Scholar

Copyright information

© Iran Polymer and Petrochemical Institute 2013

Authors and Affiliations

  1. 1.Department of Polymer EngineeringTarbiat Modares UniversityTehranIran

Personalised recommendations