Effects of multi-walled carbon nanotubes on flame retardation and thermal stabilization performance of phosphorus-containing flame retardants in polypropylene

Abstract

Effects of multi-walled carbon nanotubes (MWNTs) on flame retardation as well as thermal stabilization efficiency of two phosphorus-containing flame retardant systems i.e., ammonium polyphosphate/pentaerythritol (APP/PER) and red phosphorus (RP) in polypropylene (PP) have been investigated. Limiting oxygen index, thermo-gravimetric analysis, melt flow index, and tensile tests have been performed in this study. Moreover, the structure of the nanocomposites was characterized by scanning electron microscopy (SEM). SEM images revealed good dispersion of fillers in the polymer matrix. Furthermore, it was shown that the addition of MWNTs alone at a minimum loading level of 4 wt% improves thermal stability of PP considerably without any undesirable effect on its flow-ability and mechanical properties. Moreover, addition of MWNTs alone resulted in a slight improvement of flammability of the polymer. However, comparison between thermal stability and flame retardancy of PP samples containing a combination of MWNTs and APP/PER or RP and those of the samples containing APP/PER or RP alone proved that MWNTs interfere with thermal stabilization and flame retardation efficiency of both APP/PER and RP in the polymer.

Intumescence: Tradition versus novelty. A comprehensive review

“…Explanation was made on the basis of the restriction of intumescence by strong CNT networks formed on the flaming surfaces during combustion contrary to the enhanced intumescent char by nanoclays. Similar phenomena of CNTs were also found in PP/IFR formulations based on APP/PER and red phosphorus [200].…”

Development of Halogen‐Free Flame Retardant Acrylonitrile Butadiene Styrene (ABS) Based Composite Materials

“…Therefore, the amount of increase in MFI value is more pronounced in the presence of PER. It is known that low MFI values cause form‐filling problems and are therefore not desirable from the processing of view [27] . Therefore, this may be an advantage for filling problems.…”

“…It is known that low MFI values cause formfilling problems and are therefore not desirable from the processing of view. [27] Therefore, this may be an advantage for filling problems. Although the MFI values decreased with the addition of synergists to this mixture, it is still higher than the MFI values of AlPi-APP filled ABS composites.…”

Preparation of ZnO/MWCNT/PP composite film and its application as multifunctional protective film

“…Shahvazian et al studied effect of addition of MWCNT on LOI of PP. They showed that addition of 4% MWCNT increased LOI of PP by 2 .…”

“…This layer re‐emitted most of the incident radiation back into the gas phase from its hot surface and thus reduced the transmitted flux to the receding PP layers below it, slowing the PP pyrolysis rate . According to Shahvazian et al MWCNTs are known to improve thermal stability and reduce flammability of PP without any undesirable effect on its flow‐ability and mechanical properties . It has been reported by Cipiriano et al that the aspect ratio of MWCNT has an effect on flammability of MWCNT/Polystyrene composites.…”