Flame retardant activity of SiO2-coated regenerated cellulose fibres

Silvo Hribernik*, Majda Sfiligoj Smole, Karin Stana Kleinschek, Marjan Bele, Janko Jamnik, Miran Gaberscek

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


An alternative route to lower the flammability of viscose fibres is presented. Instead of adding a flame retardant to the viscose dope chemically, we have grown a layer of silica (SiO2) on the surface of a regenerated cellulose fibre via a sol-gel process. One set of samples was used as-received, while the other was pre-treated in an 18% NaOH solution, giving a rough, etched surface to the fibre. The different surface morphology of both fibre types triggered a different growth of silica layers. On an untreated fibre, silica formed a 300-400 nm thick surface layer containing a high density of cracks and holes. Conversely, on a NaOH pre-treated fibre, the silica layer intruded into fibre interior, adhered more tightly to the fibre structure and formed an almost defect-free, thin (100 nm) layer on the outer fibre surface. This type of silica layer increased the temperature at which the fibre started to decompose by 20 °C. It also hindered significantly the flow of oxygen to the generated volatiles during the thermal decomposition, and increased the temperature of glowing combustion of the residual char; the temperature of the corresponding exothermic peaks increased by ca. 20 °C and 40 °C. In contrast, the thermal effects of silica coatings that grew on an untreated fibre were much smaller.

Original languageEnglish
Pages (from-to)1957-1965
Number of pages9
JournalPolymer degradation and stability
Issue number11
Publication statusPublished - 1 Nov 2007
Externally publishedYes


  • Flame retardant
  • Regenerated cellulose fibres
  • Silica
  • Thermal properties

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Polymers and Plastics
  • Materials Chemistry

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