Journal of Materials Science

, Volume 43, Issue 3, pp 1057–1062 | Cite as

Mechanical properties, fire performance and thermal stability of magnesium hydroxide sulfate hydrate whiskers flame retardant silicone rubber

  • Shoulin Fang
  • Yuan HuEmail author
  • Lei Song
  • Jing Zhan
  • Qingliang He


Halogen-free flame retardant silicone rubber (SR) composites, using magnesium hydroxide sulfate hydrate (MHSH) whiskers as flame retardant have been prepared by a two-roll mill. Moreover, microencapsulated red phosphorus (MRP) was used as a synergist. Mechanical tests were performed to determine the tensile strength, elongation at break, and shore hardness of the composites. The morphology of fracture surface was observed by environmental scanning electron microscopy (ESEM). The results showed MHSH slightly reduced the tensile strength of the composites, but had obvious influence on the elongation at break. Meanwhile, Shore A hardness presented uptrend with increasing MHSH content. The addition of vinyl silicone fluid (VSF) could improve the compatibility of the MHSH whiskers in SR matrix, and therefore improved the mechanical properties of composites. The flammability properties of composites were investigated by limited oxygen index (LOI), UL-94 tests, and cone calorimetry experiments. It is found that MHSH whiskers can effectively improve the flame retardancy of SR composites due to the endothermic degradation of MHSH whiskers accompanied with the release of water vapor, and the formation of fibrous magnesia acting as a barrier layer. The incorporation of MRP in SR/MHSH whiskers system had a synergic fire retardant effect in the condensed and gas phase. In addition, thermogravimetric analysis (TGA) indicated the presence of MRP enhanced thermal stability of the SR/MHSH composites at higher temperature range, and remarkably promoted char residue yield.


Flame Retardant Silicone Rubber Cone Calorimeter Limited Oxygen Index Flammability Property 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The work was financially supported by the National Natural Science Foundation of China (No.50403014 and No.50476026), Specialized Research Fund for the Doctoral Program of Higher Education (No.20040358056), Program for New Century Excellent Talents in University, and National 11th 5-year Program (No. 2006BAK01B03, 2006BAK06B06, and 2006BAK06B07).


  1. 1.
    Jana RN, Nando GB, Khastgir D (2003) Plast Rubber Compos 32:11CrossRefGoogle Scholar
  2. 2.
    Mead JL, Tao Z, Liu HS (2002) Rubber Chem Technol 75:701Google Scholar
  3. 3.
    Wang JC, Chen YH, Jin QQ (2006) High Perform Polym 18:325CrossRefGoogle Scholar
  4. 4.
    Chiu HT, Wu JH (2005) J Appl Polym Sci 97:711CrossRefGoogle Scholar
  5. 5.
    Hornsby PR (2001) Int Mater Rev 46:199CrossRefGoogle Scholar
  6. 6.
    Lu SY, Hamerton I (2002) Prog Polym Sci 27:1661CrossRefGoogle Scholar
  7. 7.
    Wu Q, Lu JP, Qu BJ (2003) Polym Int 52:1326CrossRefGoogle Scholar
  8. 8.
    Pal K, Rastogi JN (2004) J Appl Polym Sci 94:407CrossRefGoogle Scholar
  9. 9.
    Levchik SV, Weil ED (2006) J Fire Sci 24:345CrossRefGoogle Scholar
  10. 10.
    Wu L, Jin ZL, Zhang ZH (2003) Prog Chem 15:264Google Scholar
  11. 11.
    Ouyang YX, Sui GX, Yang R, Zhuang GS (2006) Mater Manuf Proce 21:191CrossRefGoogle Scholar
  12. 12.
    Zhuang GS, Sui GX, Meng H, Sun ZS, Yang R (2007) Compos Sci Technol 67:1172CrossRefGoogle Scholar
  13. 13.
    Xiang L, Liu F, Li J, Jin Y (2004) Mater Chem Phys 87:424CrossRefGoogle Scholar
  14. 14.
    Ding Y, Zhang GT, Zhang SY, Huang XM, Yu WC, Qian YT (2000) Chem Mater 12:2845CrossRefGoogle Scholar
  15. 15.
    Lu HD, Hu Y, Xiao JF, Wang ZZ, Chen ZY, Fan WC (2006) J Mater Sci 41:363CrossRefGoogle Scholar
  16. 16.
    Liu B, Zhang Y, Wan CY, Zhang YX, Li RX, Liu GY (2007) Polym Bull 58:747CrossRefGoogle Scholar
  17. 17.
    Gilman JW (1999) Appl Clay Sci 15:31CrossRefGoogle Scholar
  18. 18.
    Ma PH, Wei ZQ, Xu G, Bao JQ, Wen XM (2000) J Mater SCI Lett 19:257CrossRefGoogle Scholar
  19. 19.
    Braun U, Schartel B (2004) Macromal Chem Phys 205:2185CrossRefGoogle Scholar
  20. 20.
    Hastie JW, Mcbee CL NTIS, Com-75-11136, 1975Google Scholar
  21. 21.
    Braun U, Balabanovich AI, Schartel B, Knoll U, Artner J, Ciesielski M, Doring M, Perez R, Sandler JKW, Altstadt V, Hoffmann T, Pospiech D (2006) Polymer 47:8495CrossRefGoogle Scholar
  22. 22.
    Cross MS, Cusack PA, Hornsby PR (2003) Polym Degra Stab 79:309CrossRefGoogle Scholar
  23. 23.
    Nazare S, Kandola B, Horrocks AR (2002) Fire Mater 26:191CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Shoulin Fang
    • 1
    • 2
  • Yuan Hu
    • 1
    Email author
  • Lei Song
    • 1
  • Jing Zhan
    • 1
  • Qingliang He
    • 1
  1. 1.State Key Laboratory of Fire ScienceUniversity of Science and Technology of ChinaHefeiPeople’s Republic of China
  2. 2.Department of ChemistryUniversity of Science and Technology of ChinaHefeiPeople’s Republic of China

Personalised recommendations