CO2 Induced Synthesis of Zn-Al Layered Double Hydroxide Nanostructures towards Efficiently Reducing Fire Hazards of Polymeric Materials

Abstract

Improving the flame retardancy of polymeric materials is an imperative yet challenging task without deteriorating their intrinsic properties. Herein, we reported a facile approach to grow zinc-aluminum layered double hydroxide (Zn-Al LDH) nanostructures on the surfaces of polymer substrates in order to overcome their high fire hazards. CO 2 induced growth of Zn-Al LDH allowed slow and homogeneous nucleation, leading to the as-synthesized Zn-Al LDH with ultra-large size (several microns) and perfect hexagonal shape. The Zn-Al LDH uniformly covered the surfaces of substrates and provided excellent flame-retardant effect. Cone calorimeter measurements revealed that the peak heat release rate of Zn−Al LDH-coated wood and rigid polyurethane foam (RPUF) were significantly decreased by 55% and 51%, respectively, compared to those of the pristine wood and RPUF; also, Zn−Al LDH-coated wood and RPUF showed notable reduction in total smoke production up to 47% and 28%, respectively. These findings demonstrate that CO 2 induced synthesis of Zn-Al LDH nanostructures is a feasible and effective solution to polymeric materials with desirable flame-retardant and smoke-suppression properties.

Flame-Retardant and Smoke Suppression Properties of Nano MgAl-LDH Coating on Bamboo Prepared by an In Situ Reaction

“…In addition, the surface of the MgAl-LB had a white film. It was found by SEM that the surface microscopic morphology of MgAl-LBs has ab-oriented hexagonal platelets compared with untreated bamboo (Figures 5(b)-5(g)), which is similar to the structural appearance reported by other researchers [12,14,19,20]. In addition, it was found that the MgAl-LDHs on the surface of MgAl-LBs gradually became denser and denser as the reaction time prolonged (Figures 5(c)-5(g)).…”

“…Liang et al introduced 5.0 wt% MgAl-LDH and 5.0 wt% melamine pyrophosphate to medium density fiberboards and found that the peak heat release rate (PHRR) and mean heat release rate (MHRR) were reduced by 27.9% and 7.5%, respectively, compared to those of samples with 3.3 wt% MgAl-LDH and 6.7 wt% melamine pyrophosphate [13]. Wang et al reported the synthesis of ZnAl-LDH coating on the surface of wood to enhance the fire resistance of wood [14]. However, as far as we know, no report currently exists on the flame retardancy of bamboo used by MgAl-LDH.…”

Application of Nanotechnology in Wood-Based Products Industry: A Review

“…Yao et al [ 180 ] applied nanomagnesium aluminium layered double hydroxide (Mg–Al LDH) to bamboo in an in situ one-step process and found that the total heat release and total smoke production were reduced by 33.3% and 88.9%, respectively, compared to those of samples without Mg–Al LDH. Wang et al [ 181 ] introduced zinc-aluminum layered double hydroxide (Zn–Al LDH) nanostructures to wood and found that the peak heat release rate (PHRR) and total smoke production were reduced by 55% and 47%, respectively, compared to those of the pristine wood [ 181 ]. Nanostructured carbon materials such as graphene was also proven to have a great potential to be used as an effective fire retardant in wood and wood-composite materials for surface protection against fire [ 182 ].…”

Advancements in Flame-Retardant Systems for Rigid Polyurethane Foam

“…Nitrogen-based FRs, such as melamine cyanurate (MC) and guanidine phosphate (GP), generate nonflammable gases and effectively suppress the flames during combustion. Furthermore, the use of nanocomposites that contain nanofillers, like layered double hydroxides (LDHs) and graphene oxide (GO), has demonstrated potential as effective flame retardants and smoke suppressants for RPUF composites [37,38]. These nanofillers have a large surface-area-to-volume ratio, improving their ability to interact with the polymer matrix and impede the spread of flames.…”