Influence of kaolinite/carbon black hybridization on combustion and thermal decomposition behaviors of NR composites

• Hybridization of fillers can improve the dispersibility of the kaolinite sheets in the rubber.
• Hybridization of fillers can generate much more retardant flame carbon layer.
• Hybridization of the carbon black and kaolinite can effectively improve the thermal stability and combustion properties of NR composites.

A series of NR composites filled with modified kaolinite (MK), carbon black (CB) and the hybrid filler contained MK and CB, were prepared by melt blending. The microstructure, combustion and thermal decomposition behaviors of NR composites were characterized by TEM, XRD, infrared spectroscopy, cone calorimeter test (CCT) and thermal-gravimetric analysis (TG). The results show that the filler hybridization can improve the dispensability and shape of the kaolinite sheets in the rubber matrix and change the interface bond between kaolinite particles and rubber molecules. NR-3 filled by 10 phr MK and 40 phr CB has the lowest heat release rate (HRR), mass loss rate (MLR), total heat release (THR), smoke production rate (SPR) and the highest char residue among all the NR composites. Therefore, the hybridization of the carbon black particles with the kaolinite particles can effectively improve the thermal stability and combustion properties of NR composites.

The presence of fillers in cured NR composites significantly decreases the HRR values. The corresponding peak HRR of NR filled by the hybrid filler of MK and CB is reduced remarkably compared to that of pure NR and NR with single filler. The hybridization of kaolinite and carbon black particles is very beneficial to improve the combustion performance.Figure optionsDownload as PowerPoint slide