Recent discoveries of two-dimensional transitional metal based materials have emerged as an excellent candidate for fabricating nanostructured flame-retardants. Herein, we report an eco-friendly ...flame-retardant for flexible polyurethane foam (PUF), which is synthesised by hybridising MXene (TiFormula: see text) with biomass materials including phytic acid (PA), casein, pectin, and chitosan (CH). Results show that coating PUFs with 3 layers of CH/PA/TiFormula: see text via layer-by-layer approach reduces the peak heat release and total smoke release by 51.1% and 84.8%, respectively. These exceptional improvements exceed those achieved by a CH/TiFormula: see text coating. To further understand the fundamental flame and smoke reduction phenomena, a pyrolysis model with surface regression was developed to simulate the flame propagation and char layer. A genetic algorithm was utilised to determine optimum parameters describing the thermal degradation rate. The superior flame-retardancy of CH/PA/TiFormula: see text was originated from the shielding and charring effects of the hybrid MXene with biomass materials containing aromatic rings, phenolic and phosphorous compounds.
Crude oil leakage from tankers, offshore platforms, drilling rigs and wells, causing severe pollution to the environment has led to irreversible damage to ocean habitat and inhabitants. It has become ...one of the greatest global environmental concerns which has recently attracted major public awareness. In addition, the contamination of sea and inhabitants. It has significantly harmed the fishing and seafood industry, and even raises health and life issues for millions of human beings. Until now, there is still no viable and practical method to effectively reduce the damage from crude oil spill. This has attracted numerous researchers’ attention. For developing an environmentally friendly and cost-effective polymer absorbent for oil spill cleaning. Recently, among all the efforts, it is proven that biomass aerogel can be used as an outstanding absorbent for oil–water separation, which is a feasible solution for tackling the crude oil issue. In this article, a comprehensive review on the current state-of-art for biomass-based aerogels utilised in the field of oil/water separation is provided. This includes the preparation procedures, fabrication processes, and the categorisation of various types of aerogels. Additionally, the future direction and technological advancement will be discussed in detail.
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A bio-flame retardant filler was synthesized via the self-polymerization of dopamine hydrochloride in alkaline condition, yielding nano-sized polydopamine (nano-PDA) particles ranging between 50 and ...100 nm in diameters. Adding a small amount (2 wt%) of the nano-PDA particles into an epoxy can remarkably reduce the value of peak heat release rate by 53.6%, exceeding the performance aluminum trihydroxide (ATH) particles at 10 wt%. The significant improvement in flame retardancy at a relatively low loading of PDA has been found to originate from several key mechanisms including radical scavenging, higher char yield, and production of CO2. Furthermore, the addition of nano-PDA in the epoxy resin increased the tensile strength by ~6%. In contrast, the addition of common flame retardant, such as ATH, to achieve the same increase in flame retardancy of epoxy would reduce the tensile strength by 22%. This improvement in mechanical properties is attributed to the better bonding between PDA particles with epoxy than ATH with epoxy.
Fabricating high-performance MXene-based polymer nanocomposites is a huge challenge because of the poor dispersion and interfacial interaction of MXene nanosheets in the polymer matrix. To address ...the issue, MXene nanosheets were successfully exfoliated and subsequently modified by long-chain cationic agents with different chain lengths, i.e., decyltrimethylammonium bromide (DTAB), octadecyltrimethylammonium bromide (OTAB), and dihexadecyldimethylammonium bromide (DDAB). With the long-chain groups on their surface, modified Ti
C
(MXene) nanosheets were well dispersed in
,
-dimethylformamide (DMF), resulting in the formation of uniform dispersion and strong interfacial adhesion within a polystyrene (PS) matrix. The thermal stability properties of cationic modified Ti
C
/PS nanocomposites were improved considerably with the temperatures at 5% weight loss increasing by 20 °C for DTAB-Ti
C
/PS, 25 °C for OTAB-Ti
C
/PS and 23 °C for DDAB-Ti
C
/PS, respectively. The modified MXene nanosheets also enhanced the flame-retardant properties of PS. Compared to neat PS, the peak heat release rate (PHRR) was reduced by approximately 26.4%, 21.5% and 20.8% for PS/OTAB-Ti
C
, PS/DDAB-Ti
C
and PS/DTAB-Ti
C
, respectively. Significant reductions in CO and CO
productions were also obtained in the cone calorimeter test and generally lower pyrolysis volatile products were recorded by PS/OTAB-Ti
C
compared to pristine PS. These property enhancements of PS nanocomposites are attributed to the superior dispersion, catalytic and barrier effects of Ti
C
nanosheets.
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A bio-flame retardant, calcium magnesium phytate (CaMg-Ph), was synthesized via the reaction of calcium chloride and magnesium chloride with phytic acid from renewable source. ...Poly(lactic acid) (PLA) biocomposites were fabricated using CaMg-Ph as a bio-sourced phosphorous additive combined with acid-treated carbon nanotubes (CNT). The thermal, mechanical and flame retardant properties of PLA biocomposites were evaluated by thermogravimetric analysis (TGA), tensile and cone calorimeter tests. The addition of the combinations (19 wt% CaMg-Ph and 1 wt% CNT) into PLA resulted in a slight increase in tensile strength (52.8 MPa), compared to 20 wt% CaMg-Ph (50.4 MPa), indicating the reinforcement effect of the CNT. The addition of 10, 20, and 30 wt% CaMg-Ph led to significant reduction in PHRR by 22%, 33%, and 38% respectively with a similar trend in THR. PLA/CaMg-Ph19/CNT1 showed lower PHRR (35.0%) and higher char yield (18.4 wt%) compared to PLA/CaMg-Ph20, suggesting the preferable flame retardant properties.
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•Nano-, submicron- and micron-sized Cu2O crystals were synthesized and confirmed.•The surface modification of Cu2O with PAPI improved the efficiency and dispersion.•Nano-sized Cu2O ...with the high surface area conduced to the complete combustion of RPUF.•The flame retardance and smoke toxicity suppression of Cu2O was explored.
The development of flame retardant rigid polyurethane foam (RPUF) composites with low smoke toxicity emission, as well as excellent mechanical properties remains a huge challenge. Herein, a facile wet chemical approach was proposed for the preparation of cuprous oxide (Cu2O) crystals with different sizes, i.e. approximately 5 nm, 100 nm and 1 μm in lateral size, which were confirmed by X-ray diffraction and transmission electron microscopy. The effect of Cu2O crystals on the combustion behavior of RPUF was evaluated by cone calorimetry and steady state tube furnace tests. Significant reduction in peak carbon monoxide (CO) production rate (by 41.2%, 67.6% and 27.9%) and total smoke production (21.6%, 16.1% and 12.2%) were realized by the incorporation of 2 wt% Cu2O into the RPUF matrix in addition to a slight reduction in peak heat release rate. Notably, nano-sized Cu2O with high specific surface area is beneficial for the complete combustion of RPUF and the conversion of CO to carbon dioxide (CO2), involving the reduction of Cu2+-Cu+-Cu0 by degraded gases and the oxidation of Cu0-Cu+-Cu2+ by oxygen. This work demonstrated that submicron-sized Cu2O is an effective smoke and toxic gases suppressant for RPUF, which is expected to find practical applications in polymeric materials.
Increasing demands in minimization of fire risks and meeting fire safety requirements by polymers require advances in knowledge of flame-retardant materials suitable for use in fire-retardancy ...applications. The present work represents the seminal review of alginate/polymer-based materials as flame retardants. Alginates are suitable for this application as they represent alternatives to petroleum-based polymer feedstocks. The content of the present work is structured into four sections: synthesis and structure, including alginate synthesis and modification by polymeric conjugation; properties, including four-stage mechanism of thermal degradation; applications, including commercial information on alginates and polymers; and flame retardancy, including comprehensive summaries of test methods and published data, discussion of key parameters, eight fire retardancy mechanisms, four char generation mechanisms, and extensive quantitative analysis of polymer char formation. The final section culminates in a first-principles approach to the prediction of quantitative polymer char formation. The goal of the review is to provide guidance for the application of alginates and alginates conjugated with fire-retardant polymers as a new generation flame retardant material.
In recent years, the applications of lithium-ion batteries have emerged promptly owing to its widespread use in portable electronics and electric vehicles. Nevertheless, the safety of the battery ...systems has always been a global concern for the end-users. The separator is an indispensable part of lithium-ion batteries since it functions as a physical barrier for the electrode as well as an electrolyte reservoir for ionic transport. The properties of separators have direct influences on the performance of lithium-ion batteries, therefore the separators play an important role in the battery safety issue. With the rapid developments of applied materials, there have been extensive efforts to utilize these new materials as battery separators with enhanced electrical, fire, and explosion prevention performances. In this review, we aim to deliver an overview of recent advancements in numerical models on battery separators. Moreover, we summarize the physical properties of separators and benchmark selective key performance indicators. A broad picture of recent simulation studies on separators is given and a brief outlook for the future directions is also proposed.
A novel and hierarchical hybrid composite (MnO
@CHS@SA@Ni) was synthesized utilizing manganese dioxide (MnO
) nanosheets as the core structure, self-assembly chitosan (CHS), sodium alginate (SA) and ...nickel species (Ni) as surface layers, and it was further incorporated into an epoxy matrix for achieving fire hazard suppression via surface self-assembly technology. Herein, the resultant hybrid epoxy composite possessed an exceptional nano-barrier and synergistic charring effect to aid the formation of a compact layered structure that enhanced its fire-resistive effectiveness. As a result, the addition of only 2 wt% MnO
@CHS@SA@Ni hybrids led to a dramatic reduction in the peak heat release rate and total heat release values (by ca. 33% and 27.8%) of the epoxy matrix. Notably, the peak smoke production rate and total smoke production values of EP/MnO
@CHS@SA@Ni 2% were decreased by ca. 16.9 and 38.4% compared to the corresponding data of pristine EP. This was accompanied by the suppression of toxic CO, NO release and the diffusion of thermal pyrolysis gases during combustion through TG-IR results. Overall, a significant fire-testing outcome of the proposed hierarchical structure was proven to be effective for epoxy composites in terms of flammability, smoke and toxicity reductions, optimizing their prospects in other polymeric materials in the respective fields.
Natural fibre biopolymer composites with both fibres and matrix being derived from biomaterials are increasingly used in demanding applications, such as sensing, packaging, building, and transport, ...and require good electrical, thermal, and flame retardant properties. Herein, an investigation of the effectiveness of functionalising nonwoven cotton/poly(lactic acid) (PLA) fibre mats with graphene oxide nanosheets has been reported by using a facile dip-coating method followed by thermal reduction for enhancing the electric, thermal, and abrasion-resistance properties. The manufacturing processes for preparing biocomposites and introducing functionality are readily scalable. Experimental results reveal that with the addition of less than 0.5 wt% graphene nanoplatelets, the biocomposites showed significant improvements in abrasion resistance, electrical conductivity, thermal conductivity, and diffusivity. Furthermore, the composite shows excellent piezo-resistivity to act as strain sensors with a gauge factor of 2.59 at strains up to 1%.
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