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•Cationic modifiers decorated Ti3C2 ultra-thin nanosheets were prepared.•TPU/modified Ti3C2 nanocomposites were fabricated via solution blending.•TPU/modified Ti3C2 nanocomposites ...showed excellent fire safety properties.
Thermoplastic polyurethane (TPU) has broad applications as lightweight materials due to its multiple advantages and unique properties. Nevertheless, toxicity emission under fire conditions remains a major concern, particularly in building fire scenarios. To circumvent the problem, it is imperative that an effective flame retardant is sought to suppress the flame and release of combustion/smoke products whilst maintaining the favorable material properties of TPU. In the current work, a simple method is proposed for the preparation and utilization of cetyltrimethyl ammonium bromide (CTAB) and tetrabutyl phosphine chloride (TBPC) modified Ti3C2 (MXene) ultra-thin nanosheets. During the cone calorimeter tests, significant reduction in peak heat release rate (51.2% and 52.2%), peak smoke production rate (57.1% and 57.4%), peak CO production (39.4% and 41.6%) and peak CO2 production (49.7% and 51.7%) were recorded by the mere introduction of 2 wt.% CTAB-Ti3C2 and TBPC-Ti3C2 to TPU. These superior fire safety properties resulting from the significant reduction of the fire, smoke and toxicity hazards are attributed to the excellent dispersion, catalytic and barrier effect of Ti3C2 ultra-thin nanosheets in TPU. Future applications of exfoliated MXene nanosheets as flame retardant appear to be very promising.
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.
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.
Graphic abstract
Background and Aims
NAFLD is considered as the hepatic manifestation of the metabolic syndrome, which includes insulin resistance, obesity and hyperlipidemia. NASH is a progressive stage of NAFLD ...with severe hepatic steatosis, hepatocyte death, inflammation, and fibrosis. Currently, no pharmacological interventions specifically tailored for NASH are approved. Ovarian tumor domain, ubiquitin aldehyde binding 1 (OTUB1), the founding member of deubiquitinases, regulates many metabolism‐associated signaling pathways. However, the role of OTUB1 in NASH is unclarified.
Methods and Results
We demonstrated that mice with Otub1 deficiency exhibited aggravated high‐fat diet–induced and high‐fat high‐cholesterol (HFHC) diet–induced hyperinsulinemia and liver steatosis. Notably, hepatocyte‐specific overexpression of Otub1 markedly alleviated HFHC diet–induced hepatic steatosis, inflammatory responses, and liver fibrosis. Mechanistically, we identified apoptosis signal–regulating kinase 1 (ASK1) as a key candidate target of OTUB1 through RNA‐sequencing analysis and immunoblot analysis. Through immunoprecipitation–mass spectrometry analysis, we further found that OTUB1 directly bound to tumor necrosis factor receptor–associated factor 6 (TRAF6) and suppressed its lysine 63–linked polyubiquitination, thus inhibiting the activation of ASK1 and its downstream pathway.
Conclusions
OTUB1 is a key suppressor of NASH that inhibits polyubiquitinations of TRAF6 and attenuated TRAF6‐mediated ASK1 activation. Targeting the OTUB1‐TRAF6‐ASK1 axis may be a promising therapeutic strategy for NASH.
During the epidemic, social media platforms were frequently used by users to express and spread negative emotions. Under emotional contagion, individual emotions gradually generalized into group ...emotions. At the same time, the public could not regulate their emotions and lacked access to release them rationally. This study explores the factors influencing the negative emotions' communication among social media users during the COVID-19 epidemic from the perspective of emotion contagion theory to discover the psychological mechanisms among the public. The questionnaire was tested for reliability and validity and then distributed online on Chinese social media platforms, and the data collected were statistically analyzed. The findings show that there are significant differences in negative emotional communication in social media among different age groups; the seven dimensions of deindividuation, risk perception, group identity, group efficacy, event stimulation, event publicness, and emotion contagion all have significant positive effects on users' negative emotional communication. This study aims to raise public awareness of negative emotions and promote the reconstruction and recovery of public mental health in the epidemic era.
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•Ti3C2 ultra-thin nanosheets were prepared via etching and ultrasonic exfoliation.•PUFs with chitosan/Ti3C2 nanocoating were fabricated via layer-by-layer approach.•Remarkable fire ...and smoke suppressions was achieved with inexpensive weight gain.
MXene/chitosan nanocoating for flexible polyurethane foam (PUF) was prepared via layer-by-layer (LbL) approach. MXene (Ti3C2) ultra-thin nanosheets were obtained through etching process of Ti3AlC2 followed by exfoliation. The deposition of MXene/chitosan nanocoating was conducted by alternatingly immersing the PUF into a chitosan solution and a Ti3C2 aqueous dispersion, which resulted in different number of bilayers (BL) ranging from 2, 5 and 8. Owing to the utilization of ultra-thin Ti3C2 nanosheets, the weight gain was only 6.9% for 8 BL coating of PUF, which minimised the unfavourable impact on the intrinsic properties of PUF. The Ti3C2/chitosan coating significantly reduced the flammability and smoke releases of PUF. Compared with unmodified PUF, the 8 BL coating reduced the peak heat release rate by 57.2%, alongside with a 65.5% reduction in the total heat release. The 8 BL coating also showed outstanding smoke suppression ability with total smoke release decreased by 71.1% and peak smoke production rate reduced by 60.3%, respectively. The peak production of CO and CO2 gases also decreased by 70.8% and 68.6%, respectively. Furthermore, an outstanding char formation performance of 37.2 wt.% residue was obtained for 8 BL coated PUF, indicating the excellent barrier and carbonization property of the hybrid coating.
Recent advancement of MXene (Ti3C2Tx) nanosheets has demonstrated the wide range of applications benefiting from its lightweight and high electrical conductivity. It possesses great potential as ...electromagnetic interference (EMI) shielding material owing to its layered structure and high conductivity. Currently, the major shortcoming of utilizing MXene as EMI shielding films is the lack of flexibility and high oxidation tendency to TiO2 in humid condition, which might significantly impair their mechanical and electrical properties. To overcome this drawback, MXene/natural rubber (NR) composite films were prepared using a suction filtration of the mixed suspension containing MXene (Ti3C2Tx) and NR. The strong interaction between NR and MXene results in the formation of lightweight, interconnected and hydrophobic composite films. The MXene/NR60% film demonstrates high water contact angle (104°) and low density (1.28 g/cm3). It also shows a tensile strength of 34 MPa, elongation at break of 4.5%, and cyclic folding endurance of 7425 times, which are 1.5, 5.6 and 62 times of pure MXene film respectively. Microscale combustion calorimeter results show that higher concentration of MXene leads to more significant flame retardancy of MXene/NR composite films. MXene/NR60% film at a thickness of 65.6 μm exhibits outstanding EMI shielding efficiency 47.8 dB. After soaking in water for 15 days followed by bending 6000 times, this film retains high EMI shielding efficiency (32.8 dB), indicating an excellent durability. The high performance MXene/NR composite films combined with their mechanical endurance provide a new material for protecting wearable electronic devices and other sensitive equipment against microwaves.
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•MXene/natural rubber (NR) films were prepared via facile suction filtration.•MXene/NR films show flexible, hydrophobic and EMI shielding properties.•Higher loading of MXene shows more remarkable flame retarded performance.•MXene/NR films exhibit outstanding durability in practical application.
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•Bio-based DPOR was synthesized via one-step method from resveratrol.•DPOR showed outstanding thermal stability and high char yield.•EP-DPOR demonstrated high mechanical strength and ...toughness.•EP-DPOR presented excellent flame retardant performance.
The integration of flame-retardant additive with both excellent thermal stability and remarkable fire-retarded efficiency into epoxy resins (EP) is highly demanded while challenging. Herein, a novel bio-based flame retardant (referred to DPOR) was synthesized via one-step reaction of resveratrol and diphenylphosphonyl chloride. The as-prepared DPOR exhibited outstanding thermal stability, with an initial thermal decomposition temperature of 438.4 °C, contributing from the reduced intermolecular π–π interaction and incremental oligomerization during the heating process. It was further utilized as additive for the manufacture of high-performance EP composites (EP-DPOR). Notably, DPOR can also act as mechanical reinforcer that enhanced the strength and toughness of EP. The EP-DPOR3 (3 wt% DPOR) showed a superior stretchability (15.9 %) and high tensile strength (59.3 MPa) compared to neat EP (12.4 %, 46.7 MPa). Additionally, the burning test results indicated that DPOR endowed the EP with greatly enhanced flame resistance, achieving a UL-94 V-0 rating with an increase of LOI values to 34.5 % at a low loading of 5 wt%. In cone calorimeter tests, it showed that heat and smoke release was effectively inhibited during combustion in comparison with EP, wherein the PHRR value of EP-DPOR was 27.5 % lower than EP. Thus, it is highly anticipated that DPOR, as a new type of bio-based flame retardant with superior thermal stability and efficient flame- retardant properties, holds a great potential for the development of next-generation flame retardant.
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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.
Acrylonitrile-butadiene-styrene (ABS) resin is a commonly used engineering thermoplastic. Nevertheless, the fire toxicity hazards (HCN, NOx, NH3 and CO) generated from the combustion of ABS remains a ...major concern, especially in building fire scenarios. To address this issue, boron dipyrromethene (BODIPY) modified MXene (Ti3C2Tx) nanosheets were prepared and utilized as a flame retardant for ABS. The loading of 0.5 wt% BODIPY-MXene resulted in the uniform dispersion in ABS. Accordingly, the tensile strength, Young's modulus and elongation at break of ABS/BODIPY-MXene0.5 were improved by 27.8%, 18.6% and 17.9% respectively compared to neat ABS, suggesting the enhanced mechanical properties. The limiting oxygen index (LOI) value was increased from 19.5% for neat ABS to 21.5% and 23.5% for ABS/BODIPY-MXene0.5 and ABS/BODIPY-MXene2.0 benefitted from the rapid carbonization. The cone calorimeter coupled with FTIR analysis showed that the reductions in peak heat release rate (−24.5%), peak smoke production rate (−18.4%), peak concentration of HCN (−33.5%), NO (−22.0%), N2O (−46.6%), NH3 (−76.0%) and CO (−28.8%) were achieved by incorporating 0.5 wt% BODIPY-MXene to ABS in comparison with pure ABS. The improved fire safety properties were primarily attributed to the excellent barrier, free radical capture, and catalytic carbonization effect of BODIPY-MXene nanosheets within ABS matrix.
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•BODIPY-MXene nanosheets were fabricated based on electrostatic interaction.•ABS/BODIPY-MXene nanocomposites were prepared via solution blending.•ABS/BODIPY-MXene exhibited improved mechanical performance.•ABS/BODIPY-MXene showed enhanced fire safety properties.
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