Synergistic flame‐retardant effect of modified hydrotalcite and expandable graphite for silicone rubber foam

Abstract

Silica gel‐coated hydrotalcite (LDHs) flame retardants (SiLDHs‐Ce) are prepared by the sol–gel method. The synergistic effect of SiLDHs‐Ce and expandable graphite (EG) on the silicone rubber foam (SRF) is studied through limiting oxygen index (LOI), Cone Calorimeter Test (CC), thermogravimetric infrared spectrometer (TG‐IR), and scanning electron microscopy. The results show that SiLDHs‐Ce and EG can improve the flame retardant properties of the SRF materials. The LOI value of the SRF material can reach 40.1% when the ratio of EG to SiLDHs‐Ce is 2:1, and the heat release rate (HRR) and total heat release (THR) are reduced by 66.60% and 52.76%, respectively, compared with the original. The minimum SPR of the SRF material is 0.010 m2 s−1 when 1 wt% SiLDHs‐Ce has been added. TG‐IR results show that the addition of EG and SiLDHs‐Ce increased the carbon residue rate of SRF materials. Results show that the residual carbon‐containing EG and SiLDHs‐Ce is denser. It is inferred that the synergistic flame retardant mechanism of SiLDHs‐Ce and EG on the SRF is mainly condensed phase flame retardant, augmented by gas‐phase flame retardant. The results of this study can provide guidance for the development of environmentally friendly silicone rubber foam.

Polyurethane Foam with High-Efficiency Flame Retardant, Heat Insulation, and Sound Absorption Modified By Phosphorus-Containing Graphene Oxide

“…Liu et al synthesized silica-coated hydrotalc (SiLDHs-Ce) using the sol–gel method and integrated both expandable graphite (EG) and SiLDHs-Ce into silicone rubber foam (SRF) to enhance its flame-retardant efficiency . Their findings indicated that SiLDHs-Ce and EG substantially improved the flame-retardant properties of SRF.…”

Flame Retardancy and Smoke Suppression of Silicone Rubber Foam with Microencapsulated Sepiolite and Zinc Borate

“…Silicone rubber foam (SiFs) is a high-performance and functional polymeric elastomer composed of Si-O-Si bonds as the main chain [1][2][3]. SiFs not only has electrical insulation, non-toxicity, durability in various weather conditions, and chemical stability, but also has the characteristics of lightweight, soundproof, and sound shock-absorbing [3,4], so it is widely used in aerospace, transportation, medicine, national defense, architecture, and other fields [5][6][7]. However, SiFs contains a large number of hydrocarbon groups, it can burn and release vast quantities of smoke when encountering a flame, which limits its promotion and application in high flame-retardant requirement fields [8,9].…”