Plastic nanocomposites containing clays are used to make plastic flame retardants stronger, but generally require clays functionalized with alkyl quaternary ammonium chlorides which involves the use of several toxic chemicals.

Miriam Rafailovich and colleagues, State University of New York at Stony Brook, USA, report a modification to the clay surfaces that is mass producible, low cost and less toxic. Resorcinol bis(diphenol phosphate) absorbs onto the clay surface to form a uniform and thermally stable surfactant coating. Using SAXS and TEM, the researchers demonstrate that these clays can be exfoliated in a range of polymers and can segregate interfaces between phase domains in polymer blends.

The organoclays produced in this manner were shown to be superior for flame retardance applications due to the segregation’s affect on the composition and mechanical properties of the resulting chars.

• Role of Surface Interactions in the Synergizing Polymer/Clay Flame Retardant Properties
  S. Pack, T. Kashiwagi, C. Cao, C. S. Korach, M. Lewin, M. H. Rafailovich,
  Macromolecules 2010, 43 (12), 5338–5351.
  DOI: 10.1021/ma100669g