Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 39
·22615-22625
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IF 12.732
Qin Zhang,Xin Liu,Jiawei Zhang,Lijie Duan,Guanghui Gao
Conductive hydrogels with anti-freezing and moisturizing properties have attracted huge attention for application in flexible electronics, which can work stably in harsh environments. However, it is challenging and urgent to enhance the environmental adaptability of hydrogels, while maintaining high conductivity. Here, a highly conductive hydrogel featuring remarkable freezing resistance and moisture-holding ability is fabricated via incorporating phytic acid (PA) into polyacrylamide/chitosan hydrogels. The addition of PA not only endows the hydrogels with a marvelous conductivity of 0.105 S cm−1 due to the ionization of PA, but also promotes their antibacterial properties against Gram-negative bacteria and Gram-positive bacteria. Besides, based on the strong hydrogen bonding between PA and water molecules, the hydrogels exhibit excellent flexibility and great conductivity (0.041 S cm−1) at −20 °C and could function well after storage for 15 days under ambient conditions. More importantly, the hydrogels can serve as reliable electrodes for electrocardiography (ECG) signal detection. Meanwhile, with the imperceptible strain perceivability (0.1% of strain) and a high gauge factor of 10.87, the hydrogel wearable sensors are capable of precisely monitoring and recognizing both drastic and subtle human motions under diverse working environments. This work provides a novel and promising method for developing flexible wearable electronics with environmental stability.
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POLYMER DEGRADATION AND STABILITY
·
2021
·
IF 5.03
Chi Huang,Ze-Yong Zhao,Cong Deng,Peng Lu,Pan-Pan Zhao,Shuang He,Si-Wei Chen,Wei Lin
A bio-based intumescent flame retardant (denoted as PIMEPA@ATH) was synthesized via metal chelation using water as the media. The PIMEPA@ATH complex aggregations was used to improve the flame retardancy of ethylene-vinyl acetate copolymer (EVA) by synergistic combination of piperazine-melamine phytate complex (denoted as PIMEPA) and aluminum hydroxide (ATH). During combustion, the in-situ growth of crystalline aluminum metaphosphate arising from PIMEPA@ATH helped to cast more compact protective barriers containing metal ions and aromatic rings. The results showed that the EVA sample containing 30 wt% PIMEPA@ATH achieved the UL-94 V0 rating without dripping in the vertical burning test and a reduction of 79% in peak heat release rate and 58% reduced peak smoke production rate in the cone calorimeter test. Moreover, the tensile properties of EVA/PIMEPA@ATH were improved compared with the EVA/PIMEPA control. Better char formation and improved interfacial adhesion were primarily responsible for the enhancements in flame retardancy and mechanical performance. This work demonstrated the flame-retardant mechanism of PIMEPA@ATH, and explored a facile and green “chelate-mediated” strategy for synthesis of bio-based and ATH chelate-mediated intumescent flame retardant.
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CHEMICAL ENGINEERING JOURNAL
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2021
·
IF 13.273
Shuaikang Yang,Ruixue Sun,Kezheng Chen
Self-healing protective coatings have attracted increasing attention as an efficient way for maintaining the performance of protection of the underlying substrate and extending substrate lifetime. Herein, we report a facile and green approach to prepare phytic acid/cerium composite coating (PA/Ce) with self-healing ability on microarc-oxidized magnesium alloy by hydrothermal treatment. Natural non-toxic phytic acid was used as an intermediate chelating agent to enhance the bonding strength between cerium salt particles and Micro-arc oxidation (MAO) layer. The morphology, cross-sectional structure, composition, self-healing property and mechanism were comprehensively investigated. The results showed that the as-prepared MAO/PA/Ce composite coating with a thickness of about 5 μm was dense and homogeneous, which bonded well with the AZ31B substrate. Electrochemical tests indicated that the MAO/PA/Ce composite coating significantly increased the corrosion resistance of the AZ31B substrate. Moreover, the composite coating showed self-healing behavior and could provide long-term corrosion protection for the substrate. The self-healing process and mechanism for the composite coating were proposed.
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Food & Function
·
2021
·Vol. 12
·期 18
·8626-8634
·
IF 5.396
Fengzhi Qiao,Xiaoting Yu,Shanshan Tie,Yannan Chen,Shuai Hou,Mingqian Tan
Food-borne nanoparticles from Undaria pinnatifida (UPFNs) were prepared and successfully applied as nanocarriers for microelement zinc delivery. UPFNs were spherical nanoparticles with average sizes of about 4.07 ± 1.09 nm, which chelated with zinc ions through amino nitrogen and carboxyl oxygen atoms as characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and 1H nuclear magnetic resonance spectroscopy. Thermodynamic analysis revealed that the overall chelation process between UPFNs and zinc ions was a spontaneous enthalpy-driven endothermic reaction. Compared to zinc sulfate, UPFN–Zn2+ showed higher solubility both in phytic acid solution and the process of gastrointestinal digestion. Meanwhile, no obvious cytotoxicity was found in UPFNs and UPFN–Zn2+. Specifically, UPFN–Zn2+ could successfully rescue cell viability, DNA replication activity and restore cell proliferation ability in zinc-deficient cells induced by a specific zinc chelator TPEN. Overall, UPFNs might serve as efficient, stable, and safe nanocarriers for zinc delivery.
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PubMed
高影响因子
ACS Catalysis
·
2021
·
IF 13.084
Xiangdong Long,Jia Wang,Guang Gao,Chao Nie,Peng Sun,Yongjie Xi,Fuwei Li
Direct oxidative amination of the sp3 C–H bond is an attractive synthesis route to obtain amides. Conventional catalytic systems for this transformation are based on transition metals and complicated synthesis processes. Herein, direct and efficient oxidative amination of the methyl C–H bond in a wide range of N-heterocycles to access the corresponding amides over metal-free porous carbon is successfully developed. To understand the fundamental structure–activity relationships of carbon catalysts, the surface functional groups and the graphitization degree of porous carbon have been purposefully tailored through doping with nitrogen or phosphorus. The results of characterization, kinetic studies, liquid-phase adsorption experiments, and theoretical calculations indicate that the high activity of the carbon catalyst is attributed to the synergistic effect of surface acidic functional groups (hydroxyl/carboxylic acid/phosphate) and more graphene edge structures exposed on the surface of carbon materials with a high graphitization degree, in which the role of acidic functional groups is to adsorb the substrate molecule and the role of the graphene edge structure is to activate O2.
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Frontiers in Materials
·
2021
·
IF 3.515
Lin Peng,Jiang Yingqiu,Ru Xiaolin,Che Wenbo,Zhang Xiaochun,Ma Lingfei,Hou Junfeng,Yu Youming
To improve the flame retardancy of bamboo materials, layer by layer (LbL) self-assembly of phytic acid (PA)-polyethyleneimine (PEI) on the surface of shaving super bamboo specimens with different solution concentrations of PA-PEI and times of LbL self-assembly was completed in this study. Fourier transform infrared analysis results showed that PEI was well assembled to the surface of bamboo specimens by a hydrogen bond with PA as intermediation. The application of PA and PEI significantly promoted the formation of carbon residue, as characterized by simultaneous thermal measurements. Particularly, the peak heat release rate and total heat release rate of bamboo self-assembly with 10 wt% PA and 10 wt% of PEI solution were reduced by 19.36 and 22.3%, respectively. The treated bamboo specimen showed increases of 35.56 and 480.70% in fire performance index and residual mass, respectively, compared to the control sample. Besides, yields of CO and CO2 were decreased by 17.77 and 17.07% in comparison with the control group, respectively. The LbL self-assembly with PA-PEI can effectively improve the flame retardancy of bamboo materials by promoting the formation of a residual char layer.
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POLYMER DEGRADATION AND STABILITY
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2021
·
IF 5.03
Guofeng Ye,Siqi Huo,Cheng Wang,Qiu Shi,Zhitian Liu,Hao Wang
The synthesis of bio-based high-efficiency flame retardants in accordance with green and facile method is critical yet very challenging for bioplastics, e.g., poly (lactic acid) (PLA). In this study, a bio-based flame retardant named as PF is synthesized by the reaction between phytic acid (PA) and furfurylamine (FA) in water. PF improves the flame retardancy of PLA at low addition. For instance, PLA composite containing only 2 wt% PF passes a UL-94 V-0 classification, and that containing 4 wt% PF exhibits a limiting oxygen index (LOI) of 28.5%, which is 46.2% higher than that of pure PLA. PF slightly reduces the peak heat release rate (PHRR) and total heat release (THR) of PLA in cone calorimeter test (CCT). In detail, 4 wt% PF reduces the PHRR from 362.2 kW/m 2 to 332.7 kW/m 2 by 8%. Additionally, PLA/PF composite is comparable to the neat PLA in terms of mechanical properties and thermal stability when a UL-94 V-0 rating is achieved. The flame-retardant mechanism analyses demonstrate that PF takes action in both gaseous and condensed phases. It is proposed that PF accelerates the generation of melting droplets to take away heat, suppresses the release of combustible gases and improves the compactness of char layer during combustion. This study provides a green and facile strategy to create bio-based high-efficiency flame retardants for the preparation of fire-safe bioplastics holding a promising future in the industry.
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MICROCHEMICAL JOURNAL
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2021
·
IF 4.821
Zeming Huang,Yin Gao,Zhengyu Huang,Donglin Chen,Jiahui Sun,Li Zhou
Exploring an effective sensor to detect Fe 3+ and phytic acid (PA) is of great importance because the levels of Fe 3+ and PA have a vital impact on human health. Herein, we report a metal-free fluorescent nanoprobe for sensitive and selective sensing of Fe 3+ and PA based on the sulfur quantum dots (SQDs). The SQDs with high fluorescence quantum yield (17.6%) and low cytotoxicity can be directly synthesized from cheap elemental sulfur by one-pot reaction. The SQDs display responsive and selective fluorescence “on–off-on” behavior towards Fe 3+ and PA based on the introduction and elimination of electron transfer effect. The addition of Fe 3+ can cause non-radiative electron transfer associated with fluorescence quenching of SQDs, while the addition of PA enables SQDs/Fe 3+ complex release Fe 3+ to recover the fluorescence of SQD S . By utilizing these SQDs as a fluorescent nanoprobe, it shows good linear relationship for Fe 3+ and PA in the range of 0.05–120 µM and 0–12 µM, respectively. Moreover, its limit of detection (LOD) for Fe 3+ and PA can reach as low as 102 and 73.5 nM, respectively, which compares favorably to many reported fluorescent probes. Additionally, the use of this SQDs-based sensor to detect PA in fresh carrot and lettuce samples was examined with satisfactory performance.
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POLYMERS FOR ADVANCED TECHNOLOGIES
·
2021
·Vol. 32
·期 11
·4440-4449
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IF 3.665
Qianqian Guo,Yufan Yang,Lu Li,Jun Sun,Wei Liu,Xiaoyu Gu,Hongfei Li,Sheng Zhang
Polyethylene terephthalate (PET) fabric has been widely used in textile industry for decades. However, it faces poor flame retardant performance and dripping problem during burning. In our study, a novel intumescent flame retardant coating containing bio-materials ammonium phytate (APA) and cyclodextrin (CD) had been constructed on PET fabrics surface via pad-dry-cure method. The fire performance, mechanical properties and bio-safety of APA/CD coated fabric were evaluated. PET fabric coated with 19%APA/6%CD showed a limiting oxygen index value of 29.5% with self-extinguish from fire and no melt dripping during the vertical burning test. Cone calorimetry test revealed that treated PET fabric significantly suppressed heat release and mass loss. The peak heat release rate was decreased from 277.1 KW/m 2 of PET fabric to 158.3 KW/m 2 of PET-19%APA/6%CD sample. Furthermore, the residue of treated fabric after combustion was also increased significantly. Tensile strength test showed that the maximum force of fabric was improved by 109.5% in warp direction and 24.2% in weft direction after treatment. Skin irritation test indicated that APA/CD coated PET fabric did not cause erythema and edema to rabbit skin and exhibited satisfactory bio-safety. All these results suggest that this study proposes a viable way to produce bio-safety flame retardant PET fabrics.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Yuchun Li,Shuang Qiu,Jun Sun,Yajing Ren,Shuheng Wang,Xingguo Wang,Wenjia Wang,Hongfei Li,Bin Fei,Xiaoyu Gu,Sheng Zhang
Despite the advantages of biological compatibility and high transparency, there are still some drawbacks for Poly(lactic acid) (PLA) such as highly flammability and poor ultraviolet resistance. Herein, a fully bio-based additive (PA@CHTM) with a core–shell structure is synthesized by chitosan microspheres and phytic acids. The introduction of PA@CHTM simultaneously improves the mechanical properties, flame retardancy, and UV-blocking performance of PLA, accompanied by an accelerated degradation capacity in soil. By the presence of 9 wt% PA@CHTM in the PLA composite sample, the limiting oxygen index value is increased from 18.2% to 29.6%, and the UL-94 test grade is improved to V-0. The tensile strength is well maintained and Young's modulus is sharply increased for PLA/PA@CHTM composites. Moreover, the photoaging process of PLA can be significantly delayed due to the excellent free radical quenching capacity of PA@CHTM. Only less than 10% UV light can be penetrated for the PLA/9%PA@CHTM sample, and the ultraviolet protection factor is increased from 0.77 of control PLA to 30.07. More importantly, the addition of PA@CHTM can accelerate the degradation of PLA, which is of significance for biodegradable materials. This work firstly provides a green strategy to fabricate fully bio-based polymer composites with high performance, long service life, and rapid degradation in soil.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Jiao Tang,Junxiang Tang,Hao Lei,Yong Chen,Jiang Zhao,Xiaoqiang Wang,Ning Pan
In this study, a novel, high surface area iron phosphonate (IP) for highly efficient adsorption of uranyl ion in acidic medium was described. The as-prepared IP was amorphous with its specific surface area and total pore volume as high as 268 m 2 /g and 1.04 cm 3 /g, respectively. Particularly, the as-prepared IP with ferrous ions and oxygen, nitrogen-bearing functional groups prove excellent U(VI) adsorption capacity (154.6 mg/g) as compared to that of amorphous FePO 4 (67.3 mg/g) and Fe 3 (PO 4 ) 2 (H 2 O) 8 (33.8 mg/g). Surprising, the saturation adsorption capacity could achieve up to 353.9 mg/g. Besides, the IP also had a fast adsorption rate for attaining adsorption equilibrium within 20 min, and followed pseudo-second-order kinetic and Freundlich models. Moreover, both the Dubinin-Radushkevich isotherm adsorption model and the value of enthalpy indicated a chemisorption process. Otherwise, the Na + -independent U(VI) adsorption on IP and the adsorption-desorption isotherm studies revealed that inner-layer surface complexation is the control step for U(VI) adsorption process, and the adsorbent featured an irreversible adsorption process. The structure and functional groups of the adsorbent remained unchanged after capture of U(VI). Further, X-ray photoelectron spectra (XPS) analysis demonstrated that the capture mechanism of U(VI) on IP from acidic aqueous solution was due to not only redox reaction, but also ascribed to the coordinated chemical adsorption.
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PubMed
高影响因子
Polymers
·
2019
·Vol. 11
·期 10
·1564
·
IF 3.164
Tong Wang,Xuan Zhang,Zichao Wang,Xiuzhong Zhu,Jie Liu,Xin Min,Tao Cao,Xiaodong Fan
Stimuli-responsive conductive hydrogels have a wide range of applications due to their intelligent sensing of external environmental changes, which are important for smart switches, soft robotics, and flexible sensors. However, designing stimuli-responsive conductive hydrogels with logical operation, such as smart switches, remains a challenge. In this study, we synthesized pH-responsive conductive hydrogels, based on the copolymer network of acrylic acid and hydroxyethyl acrylate doped with graphene oxide. Using the good flexibility and conductivity of these hydrogels, we prepared a flexible sensor that can realize the intelligent analysis of human body motion signals. Moreover, the pH-responsive conductive hydrogels were integrated with temperature-responsive conductive hydrogels to develop logic gates with sensing, analysis, and driving functions, which realized the intellectualization of conductive hydrogels.Keywords:stimuli-responsive conductive hydrogels;pH-responsive;composite hydrogels;flexible sensors;logic gates
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