Flame retardancy of microcellular poly(lactic acid) foams prepared by supercritical CO2-assisted extrusion

Dániel Vadas, Tamás Igricz, Johan Sarazin, Serge Bourbigot, G. Marosi, Katalin Bocz

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Flame-retardant-treated cellulose (FR-cell) was used as bio-based charring agent in combination with ammonium polyphosphate (APP) based intumescent flame retardant (IFR) system to reduce the flammability of poly(lactic acid) (PLA) foams produced by supercritical carbon dioxide (sc-CO2) assisted extrusion. FR-cell was obtained by surface treatment of cellulose with diammonium phosphate (DAP) and boric acid (BA). To enhance foamability, the inherently low melt strength and slow crystallization rate of PLA was increased by adding epoxy-based chain extender (CE) and montmorillonite (MMT) nanoclay, respectively. The morphology of the foams was examined using water displacement method, scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Thermal properties were assessed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Flammability was evaluated by limiting oxygen index (LOI) measurements, UL-94 tests and pyrolysis combustion flow calorimetry (PCFC). The continuous extrusion foaming technique allowed the preparation of low density PLA foams with uniform microcellular structure and void fractions higher than 90% accompanied with increased crystallinity of up to 19%. Despite the high expansion ratios (i.e. high surface area), the PLA foams showed excellent flame retardancy, UL-94 V-0 rate and LOI value of 31.5 vol% was achieved with an additive content as small as 19.5%. However, the flame retardant synergism evinced between IFR and MMT proved to be less pronounced in the expanded foams compared to bulk materials with identical additive contents.

Original languageEnglish
Pages (from-to)100-108
Number of pages9
JournalPolymer Degradation and Stability
Volume153
DOIs
Publication statusPublished - Jul 1 2018

Fingerprint

Flame Retardants
flame retardants
lactic acid
Flame retardants
Lactic acid
foams
Extrusion
Foams
flames
cellulose
Cellulose
Bentonite
flammability
Flammability
montmorillonite
Clay minerals
heat measurement
charring
Oxygen
Polyphosphates

Keywords

  • Cellulose
  • Extrusion foaming
  • Flame retardancy
  • Intumescence
  • Poly(lactic acid)

ASJC Scopus subject areas

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

Cite this

Flame retardancy of microcellular poly(lactic acid) foams prepared by supercritical CO2-assisted extrusion. / Vadas, Dániel; Igricz, Tamás; Sarazin, Johan; Bourbigot, Serge; Marosi, G.; Bocz, Katalin.

In: Polymer Degradation and Stability, Vol. 153, 01.07.2018, p. 100-108.

Research output: Contribution to journalArticle

Vadas, Dániel ; Igricz, Tamás ; Sarazin, Johan ; Bourbigot, Serge ; Marosi, G. ; Bocz, Katalin. / Flame retardancy of microcellular poly(lactic acid) foams prepared by supercritical CO2-assisted extrusion. In: Polymer Degradation and Stability. 2018 ; Vol. 153. pp. 100-108.
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