Effect of modified layered double hydroxide on the flammability of intumescent flame retardant PP nanocomposites

Abstract

The dodecyl sulfate intercalated CaMgAl-hydrotalcites (layered double hydroxides [LDHs]) were successfully prepared by co-precipitation method, and characterized by X-ray diffraction analysis, infrared spectroscopy (Fourier transform infrared spectra [FT-IR]), thermogravimetry (TG-DTA), scanning electron microscope, and BrunnerÀEmmetÀTeller (BET). The prepared LDHs were added to the intumescent flame retardant (IFR) polypropylene (PP) nanocomposites, and the limiting oxygen index method (LOI), vertical combustion method (UL-94), cone calorimetry (CCT), and other test methods were used to study its thermal stability and combustion performance. The results showed that when the flame retardant was composed of 23 wt% IFR and 2 wt% O-SDS-LDHs, the LOI value of the material was increased to 31.5%, reaching the V-0 level, and the flame retardant performance was significantly improved. The results also showed that there was a significant synergistic effect between IFR and O-SDS-LDHs, which could improve the thermal stability and graphitization degree of PP nanocomposites. In addition, the peak heat release rate, total heat release, and total smoke production of the PP/IFR/ O-SDS-LDHs system were 177 kW/m 2 , 101 MJ/m 2 , and 15.4 m 2 , respectively, which were 82.2%, 51.0%, and 23.0% lower than those of pure PP, respectively. These improvements could be attributed to the presence of dense and continuous char layer formed by the synergistic effect. K E Y W O R D Scomposites, nanoparticles, nanowires and nanocrystals, synthesis and processing techniques, thermal properties, thermogravimetric analysis

The synergism effect of montmorillonite on the intumescent flame retardant thermoplastic polyurethane composites prepared by selective laser sintering

“…Synergists can be used with IFR such as nano-SiO 2 , montmorillonite (MMT), 4A zeolite, layered double hydroxides (LDHs), and carbon materials. [23][24][25][26][27][28] Ji et al [29] added 10 wt% IFR and 1 wt% CNTs into the TPU; LOI was 30.1% and passed the UL-94 V-0 rating, compared with 10 wt% IFR (LOI 28.0%, UL-94 V-2 rating) and 15 wt% IFR (LOI 30.1%, UL-94 V-2 rating), which indicated that a spot of CNTs had a synergistic flame retardant effect with IFR. Chen et al [30] used fumed silica to synergize with ammonium polyphosphate (APP) in the TPU; LOI was 32.3% with 18.75 wt% APP and 1.25 wt% fumed silica.…”

Flame retardancy of carboxylated polyhedral oligosilsesquioxane modified layered double hydroxide in the process of leather fatliquoring

“…From Figure 6b, the decomposition rate of MZBMSO/P(POSS‐MAA)‐LDHs treated leather was much faster than that of MZBMSO treated leather, but the temperature of MZBMSO/P(POSS‐MAA)‐LDHs treated leather at maximum degradation rate was higher than MZBMSO treated leather. This indicated that P(POSS‐MAA)‐LDHs played the role of catalytic carbonization when exposed to heat, and formed a barrier on the surface of collagen fibers, thereby improving the heat resistance of collagen fibers 42 . The results showed that the introduction of P(POSS‐MAA)‐LDHs enabled to improve the thermal stability of leather 43 …”

“…This indicated that P(POSS-MAA)-LDHs played the role of catalytic carbonization when exposed to heat, and formed a barrier on the surface of collagen fibers, thereby improving the heat resistance of collagen fibers. 42 The results showed that the introduction of P(POSS-MAA)-LDHs enabled to improve the thermal stability of leather. 43 The cone calorimeter is the most ideal instrument that characterize the combustion performance of materials, and the data enable to be used to evaluate the combustion behavior of materials in a fire.…”

Effect of layered double hydroxide on the flame retardancy of intumescent flame retardant thermoplastic polyurethane composites prepared by selective laser sintering

“…Numerous studies have identified that traditional halogen-based flame retardants are the most effective and economic flame retardants. 15,16 However, halogen flame retardants are toxic and environmentally harmful. Resultantly halogen-free flame retardants have been focused on to a greater extent based on their environmental friendliness.…”

“…LDHs present good flame retardant properties and smokesuppressing properties due to its special structure and chemical component. 15 Ren et al 31 synthesized a MgFe-LDHs, after which LDHs and APP were introduced into the TPU to reduce smoke density during combustion. Their results evidenced that through combining 16 wt% APP and 4 wt% LDHs, the maximum smoke density (D s,max ) declined from 222.5 to 44.0, suggesting that LDHs within a polymer matrix offer effective smoke-suppression.…”