JOURNAL OF MATERIALS SCIENCE
·
2022
·Vol. 57
·期 5
·3280-3294
·
IF 4.682
Xiang Xu,Zhu Ying,Yin Mingyu,Xia Shuang,Guo Chunwen
Reduced graphene oxide (rGO) has been studied as a possible substitute for graphene in many applications because it is cheaper and easier to prepare than graphene. RGO with low reduction degree has good hydrophilicity and can be stably dispersed in water. These properties are conducive to the preparation of hydrophilic composites. Here, the method of microwave reduction of GO suspension to prepare rGO with low reduction degree was studied. By controlling the reduction time, the rGO samples with different reduction degrees are prepared. After studying the characterization data of rGO with different reduction degrees, we propose the hypothesis of the reduction pathway of GO suspension, that is, the oxygen-containing groups on the surface of GO sheet are reduced first. FTIR, TGA and XPS data verify this hypothesis and are consistent with the simulation results. Therefore, the low reduction degree rGO has a large-area conjugated structure similar to graphene and also has good hydrophilicity due to the residual oxygen-containing groups on the periphery of the rGO sheet. This structure provides convenience for its composite with hydrophilic materials. In sum, the microwave reduction of GO suspension provides a simple method for researchers to prepare rGO with low reduction degree.
Graphical abstract
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2021
·Vol. 28
·期 10
·1-13
·
IF 3.097
He Jing,Yu Tao,Chen Shaokai,Li Yan
A new thermoset PLA resin was synthesized. The structure and performance of the thermoset PLA resin were characterized by Fourier transform infrared spectroscopy (FTIR), 1 H Nuclear Magnetic Resonance ( 1 H-NMR), 13 C Nuclear Magnetic Resonance ( 13 C-NMR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) testing methods. The results indicate that thermoset PLA resin has been synthesized successfully, and the thermal stability of thermoset PLA is better than that of linear PLA. Thermoset PLA resin and ramie/thermoset poly(lactic acid) (PLA) composites were prepared by casting and hot-pressing, respectively. The degradation behavior was evaluated by surface morphology observation, scanning electron microscope (SEM), pH detection and FTIR analysis. The results show that the thermoset PLA resin fully degrades after 20 days, and the degradation rate of ramie/thermoset PLA composites is only 45.27% after 30 days, which is lower than that of thermoset PLA. The reason is due to that ramie fabric as the barrier hinders the moisture and microorganisms enter the interior of the composites. Moreover, according to the FTIR analysis, the ester groups of thermoset PLA are firstly hydrolyzed, and thermoset PLA is decomposed into low molecular weight oligomers. Then thermoset PLA and oligomers are continuously hydrolyzed by moisture and microorganisms until mineralized into H 2 O and CO 2 . Besides, the soil pH value detection proves that no acidic or alkaline harmful degradation products are produced during the soil degradation process.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF FOOD SCIENCE AND TECHNOLOGY-MYSORE
·
2021
·Vol. 59
·期 6
·2381-2391
·
IF 2.701
Zhai Xinyu,Ao Huanping,Liu Wenhui,Zheng Jiaxin,Li Xingjie,Ren Difeng
Rosa roxburghii pomace was treated by steam explosion (SE) at 0.87 MPa for 97 s. After SE treatment, the Insoluble dietary fiber (IDF) content of Rosa roxburghii pomace decreased from 45.13 ± 0.23 to 30.01 ± 0.15%, and the soluble dietary fiber (SDF) content increased from 9.31 ± 0.07 to 15.82 ± 0.31%. The structure of IDF and SDF after SE showed that the original compact structures were destroyed, and the specific surface areas increased. Thermal analysis showed that the thermal stability of the modified SDF was improved. However, SE did not change the crystal structure and functional group composition of IDF and SDF. Physicochemical analysis indicated that IDF had better hydration capacity after SE treatment, and the oil-holding capacities of IDF and SDF were also significantly improved. SE is an effective method to improve the utilization of Rosa roxburghii pomace and a feasible method for modification of dietary fiber.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Bionic Engineering
·
2021
·Vol. 18
·期 6
·1378-1390
·
IF 2.682
Li Pengfei,Ruan Liming,Wang Ruofan,Liu Tianqi,Song Gao,Gao Xiaofei,Jiang Guohua,Liu Xiaoyan
Nanofibers (NFs) have been widely used in tissue engineering such as wound healing. In this work, the antibacterial ZnO quantum dots (ZnO QDs) have been incorporated into the biocompatible poly (ε-caprolactone)/collagen (PCL/Col) fibrous scaffolds for wound healing. The as-fabricated PCL-Col/ZnO fibrous scaffolds exhibited good swelling, antibacterial activity, and biodegradation behaviors, which were beneficial for the applications as a wound dressing. Moreover, the PCL-Col/ZnO fibrous scaffolds showed excellent cytocompatibility for promoting cell proliferation. The resultant PCL-Col/ZnO fibrous scaffolds containing vascular endothelial growth factor (VEGF) also exhibited promoted wound-healing effect through promoting expression of transforming growth factor-β (TGF-β) and the vascular factor (CD31) in tissues in the early stages of wound healing. This new electrospun fibrous scaffolds with wound-healing promotion and antibacterial property should be convenient for treating wound healing.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2021
·Vol. 147
·期 15
·8145-8155
·
IF 4.626
Tao Lili,Xu Yue,Liu Lubin,Li Bin,Xu Miaojun
A novel mono-component P/N/B-containing intumescent flame retardant poly(methylphosphonic-boric acid piperazine neopentylgcol ester) named MBPNE was synthesized. The chemical structure of MBPNE was analyzed by FTIR, 13 C and 31 P solid-state NMR tests. The results of thermal gravimetric analysis indicated that MBPNE possessed excellent charring capability, and its residual char was 27.5 mass% at 800 °C. Besides, MBPNE occurred melting and expansion process during charring evolution process. MBPNE was used to prepare flame retardant polyolefin elastomer (POE) composites. The 1.6 mm POE/MBPNE specimens achieved UL-94 V-0 rating and their LOI value was 25.5% when 22 mass% MBPNE was incorporated. The sheet was extinguished quickly after departing the flame, and no dripping appeared. Furthermore, the incorporation of MBPNE effectively enhanced the residual char mass after cone calorimeter tests, and the heat release was suppressed. The compact, expanded, partially graphitized and coherent char layer was generated on POE composites surface during burning process and exerted isolation effect in condensed phase. Meanwhile, the degradation products of MBPNE quenched active free radicals in gaseous phase, which effectually interrupted the combustion chain reaction of POE composites. Consequently, the POE composites were endowed excellent flame retardant performance.
✓ 已验证
产品关联
DOI
高影响因子
BMC BIOTECHNOLOGY
·
2021
·Vol. 21
·期 1
·1-9
·
IF 2.563
Zhang Zhiwei,Liu Yang,Zhao Jing,Li Wenqiang,Hu Ruiwen,Li Xia,Li Aitao,Wang Yaping,Ma Lixin
Background The unnatural amino acid, L-2-aminobutyric acid (L-ABA) is an essential chiral building block for various pharmaceutical drugs, such as the antiepileptic drug levetiracetam and the antituberculosis drug ethambutol. The present study aims at obtaining variants of ω-transaminase from Ochrobactrum anthropi (OATA) with high catalytic activity to α-ketobutyric acid through protein engineering.Results Based on the docking model using α-ketobutyric acid as the ligand, 6 amino acid residues, consisting of Y20, L57, W58, G229, A230 and M419, were chosen for saturation mutagenesis. The results indicated that L57C, M419I, and A230S substitutions demonstrated the highest elevation of enzymatic activity among 114 variants. Subsequently, double substitutions combining L57C and M419I caused a further increase of the catalytic efficiency to 3.2-fold. This variant was applied for threonine deaminase/OATA coupled reaction in a 50-mL reaction system with 300 mM L-threonine as the substrate. The reaction was finished in 12 h and the conversion efficiency of L-threonine into L-ABA was 94%. The purity of L-ABA is 75%, > 99% ee. The yield of L-ABA was 1.15 g.Conclusion This study provides a basis for further engineering of ω-transaminase for producing chiral amines from keto acids substrates.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 29
·期 4
·6278-6293
·
IF 4.223
Zhu
Jing,Zhao Xuan,Yang Mi,Zheng Bo,Sun Chengjun,Zou Xiaoli,Liu Zhen,Harada Kouji H.
Maternal exposure to benzene and related compounds, trichloroethylene, and polycyclic aromatic hydrocarbons has been suggested as risk factors for reproductive and developmental problem. In different countries and groups, there are differences in socioeconomic circumstances, consumer products, dietary habits, lifestyles, and so on, resulting in different exposure risks from these chemicals. This study investigated the correlation between their metabolite concentrations and socioeconomic, demographic, and dietary factors to explore the possible exposure source of the concerned pollutants in pregnant women. We conducted biological monitoring to assess the exposure of these chemicals using urine samples from 590 to 639 pregnant women during 2nd or 3rd trimester of pregnancy in six cities of China. Socioeconomic and demographic characteristics and dietary habits were collected from questionnaires. The detection rate was over 74% of the urine samples for all metabolites. Compared with the Fourth National Report on Human Exposure to Environmental Chemical concentrations for females (FNRHEEC, the US Centers for Disease Control and Prevention), the metabolite concentrations of benzene compounds and trichloroethylene, excluding MA reported here, were higher. Principal component analysis results showed that SBMA and MHA could be proxy of the principal sources of metabolites for benzene compounds. The concentrations of SBMA and MA were higher in Fuzhou and Wuhan, respectively. The concentration of DCVMA was higher in Shenzhen, Xi’an, and Nanning, and the concentration of PGA was higher in Fuzhou, Wuhan, and Xi’an. Also, the 1-OHPG concentration in Wuhan is higher than that in Fuzhou and Shenzhen. Unhealthy dietary habits, using cosmetics and indoor exposure, contacting chemical solvent during pregnancy were associated with increased benzene compounds, trichloroethylene, and PAH exposure. There were significant positive associations between 1-OHPG level and maternal BMI, low education status, and cooking without a range hood. Pregnant women in China may be at a greater risk of exposure to most of the target compounds than US females, and their exposure levels varied in different regions. Some adverse environmental and behavioral factors may increase the exposure of environmental toxins, which can urge people to take measures to reduce the health risk to pregnant women during pregnancy.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2021
·Vol. 56
·期 35
·19466-19475
·
IF 4.22
Ding Jinjin,Zhang Mengke,Wei Xiaoqing,Song Wenwu,Wang Jin,Sun Tongming,Zhu Jinli,Wang Minmin
A rational structural strategy to design rambutan-like NiFe-LDH nanocluster arrays electrode via a buffer-salt-assisted hydrothermal method was reported. For our developed electrode, large stable current density of 100 and 200 mA cm −2 at overpotential of only 283 and 300 mV in oxygen evolution reaction in alkaline electrolyte was obtained, which is dramatically lower than many previous reported overpotentials. It also exhibits low Tafel slope at current range from 10 to 25 mA cm −2 (56.47 mV dec −1 ). Further analysis demonstrates the key role of higher carriers of the rambutan-like NiFe-LDH nanocluster arrays electrode in boosting the water-splitting performance of the resulting system. Benefiting from the fine geometry shape of the self-supported nanocluster nanoarrays electrode, the transfer process of the reactants and oxygen/hydrogen bubbles is accelerated. In addition, a 19-time enhancement of carrier concentration for our developed rambutan-like NiFe-LDH nanoclusters (2.9 × 10 29 m −3 ) is obtained. Notably, the resultant rambutan-like NiFe-LDH nanocluster arrays electrode exhibits enhanced stability (in high and low current density) for the full water splitting in 1 M KOH, remaining nearly 100% of the original current density after continued testing for 20 h. This finding may provide new insight on rational structural design LDH nanostructures with high performance for electrocatalysis. Graphic abstract A highly hydrophilic NiFe-LDH nanocluster arrays electrode is developed for efficient full water splitting. Large and stable current density of 200 mA cm −2 is obtained at overpotential of 300 mV. Besides, the faraday efficiency is nearly 100%.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMERS AND THE ENVIRONMENT
·
2021
·Vol. 30
·期 3
·1127-1140
·
IF 3.667
Wang Jun,Yang Le,Li Xiaolong,Luo Zhu,Li Jianjun,Xia Xiaosong,Linghu Changkai
Incompatible polypropylene (PP) and polyethylene (PE) are difficult to separate in mixed recycling streams such as waste plastic packaging, which makes polyolefin mixtures unsuitable for high-quality products. In this work, based on the free radical branching reaction, a co-branching reaction of isotactic polypropylene (iPP) and high-density polyethylene (HDPE) blends was carried out in the presence of the peroxide, free radical regulator and multifunctional acrylate monomer, and a star-like long-chain branching (LCB) copolymer was obtained. The effect of in situ compatibilization on the structures and mechanical properties of iPP/HDPE was investigated, and the compatibilization mechanism was discussed. Results showed that the mechanical properties of the modified blends were largely improved, and efficient in-situ compatibilization of iPP and HDPE could be taken place in a wide process window. Moreover, the sizes of the dispersed phase in the modified blends were clearly decreased, and the interfacial thickness increased. Compared with the pure iPP/HDPE blend, the initial crystallization temperature of iPP in the modified iPP/HDPE blend was increased, and long branched chains of the LCB copolymers were physically entangled with the chemical identical homopolymers or even participated in the crystallization of iPP and HDPE. Thanks to the in situ compatibilization strategy, the compatibility of iPP/HDPE was significantly improved.
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 29
·期 3
·4461-4473
·
IF 4.223
Shao Jiang,Zhang Yi,Liu Zongtang,Fei Zhenghao,Sun Yufeng,Chen Ziyan,Wen Xiaoju,Shi Weizhong,Wang Dandan,Gu Chenggang
Organic palygorskite (OP)–supported Pd/Fe nanoparticles composite (OP-Pd/Fe) was prepared by stepwise reduction method. The removal capacity of 4,4′-dibrominated diphenyl ether (BDE15) by OP-Pd/Fe was compared with other various materials. For better understanding the possible mechanism, the synthesized and reacted OP-Pd/Fe materials were characterized by TEM, SEM, XRD, and XPS, respectively. The effects of major influencing parameters on the degradation of BDE15 were also studied. Benefit from the synergistic effect of the carrier and bimetallic nanoparticles, BDE15 could be completely debrominated into diphenyl ether (DE) under suitable conditions. A two-stage adsorption/debromination removal mechanism was proposed. The degradation of BDE15 with OP-Pd/Fe was mainly stepwise debromination reaction, and hydrogen transfer mode was assumed as the dominated debromination mechanism. The removal process fitted well to the pseudo first-order kinetic equation. The observed rate constants increased with increasing Pd loading and OP-Pd/Fe dosage while decreased with increasing initial BDE15 concentration, the tetrahydrofuran/water ratio, and the initial pH of the solution. The work provides a new approach for the treatment of PBDEs pollution.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 17
·22232-22244
·
IF 2.478
Liu Ting,Zhai Xiaoyu,Liu Jiaxiang
Indium tin oxide (ITO) is a promising transparent conducting oxide material for photoelectric devices. In this work, the low-resistivity cubic ITO (c-ITO) nanopowders were synthesized via polyacrylamide gel route. The orthogonal experiment design was applied to optimize preparation process that was as follows: n (AM)/ n (MBAM) = 25:6, c (In 3+ ) = 0.3 mol/L, calcination temperature ( T ) = 700 °C, holding time ( t ) = 9 h. Subsequently, the thermal decomposition process of ITO xerogel, crystal structure, morphology, and electrical conductivity of the optimum sample were characterized systematically. The results indicated that the thermal decomposition of ITO xerogel was a multi-step kinetic reaction process, and the activation energy of reaction depended on the conversion of ITO xerogel. The powders were well indexed to cubic ITO crystal phase, and presented a concentrated particle size distribution of 34–54 nm and nearly spherical-like morphology. The low-resistivity value of 0.161 Ω·cm was obtained under the optimum preparation process. Moreover, the formation mechanism of ITO nanopowders prepared via polyacrylamide gel route was also investigated. The synthesized ITO nanopowders with low resistivity present wide application prospects of next-generation ITO functional materials.
✓ 已验证
产品关联
DOI
高影响因子
Nano Research
·
2021
·Vol. 15
·期 2
·1383-1392
·
IF 8.897
Yan Nina,Zheng Zhiyu,Liu Yunliang,Jiang Xizhi,Wu Jiamin,Feng Min,Xu Lei,Guan Qingbao,Li Haitao
As photothermal conversion agents, carbon nanomaterials are widely applied in polymers for light-triggered shape memory behaviors on account of their excellent light absorption. However, they are usually derived from non-renewable fossil resources, which go against the demand for sustainable development. Biomass-derived carbon nanomaterials are expected as alternatives if they are designed with good dispersibility as well as splendid photothermal properties. Up to date, very few researches focused on this area. Herein, we report a novel light-triggered shape memory composite by incorporating renewable biomass-derived carbon nanomaterials into acrylate polymers without deep purification and processing. These functionalized carbon nanomaterials not only have stable dispersion in polymers as fillers, but also can endow the polymers with excellent and stable thermal and photothermal responsive properties in biological friendly environment. With the introduction of biomass-derived carbon nanomaterials, the mechanical properties of the composites are also further enhanced with the formation of hydrogen bonding between the carbon nanomaterials and the polymers. Notably, the doping of 1% carbon nanomaterials endows the polymer with sufficient hydrogen bonds that not only exhibit excellent thermal and photothermal responsive properties, but also with enough space for the motion of chains. These properties make such composite a promising and safe candidate for shape memory applications, which provide a new avenue in smart fabrics or intelligent soft robotics.
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）