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Nowadays, developing microwave absorption materials (MAMs) with thin thickness, wide-frequency effective absorption bandwidth (EAB) and strong absorbing capacity is an urgent requirement to tackle the increasingly serious electromagnetic radiation issue. Herein, we report a novel high-performance MAMs by growing Fe3O4 nanoparticles on activated porous carbon derived from egg white via a facile carbonization and subsequent hydrothermal approach. The resultant composite features three-dimensional hierarchical porous carbon embedded with Fe3O4 nanoparticles. Benefiting from the balanced impedance matching and the multi-loss that involve the conductive loss, dielectric loss, dipolar/interfacial polarization and magnetic loss, the prepared composite achieves a minimum reflection loss (RL) of -43.7 dB at 9.92 GHz and a broad EAB (RL

Here, a novel nitrogen-doped carbon nano-material (N-CGNM) with hierarchically porous structure was prepared from spent coffee ground for efficient adsorption of organic dyes by a simple one-step carbonization process (the uniform mixture consists of spent coffee ground, urea, and CaCl2 with the ratio of 1:1:1, which was heated to 1000 °C with a rate of 10 °C min−1 and held at 1000 °C for 90 min in N2 atmosphere to carry out carbonization, activation, and N-doping concurrently). The morphology and structure analysis show that the prepared N-CGNM exhibits hierarchical pore structure, high specific surface area (544 m2/g), and large numbers of positively charged nitrogen-containing groups. This unique structure and chemical composition endow N-CGNM with an excellent adsorption capacity toward anion Congo red (623.12 ± 21.69 mg/g), which is obviously superior to that (216.47 ± 18.43 mg/g) of untreated spent coffee ground-based carbon nano-materials (CGM). Oppositely, the adsorption capacity of N-CGNM towards cation methylene blue is inferior to that of CGM due to the existence of electrostatic repulsion. These findings show a great guidance for the development of low-cost but efficient selective adsorbent.

In order to determine the influence of spheroidization process of Ammonium dinitramide’s hazard grade, the hazardous division of Ammonium dinitramide before and after spheroidization is studied by using hazard classification procedure for combustible and explosive substances and articles standard (WJ20405) and hazard classification method and criterion for combusitible and explosive substances and articles standard (WJ20404). The research results show that spheroidization process can significantly improve the temperature stability of Ammonium dinitramide and significantly reduce friction sensitivity and impact sensitivity of Ammonium dinitramide. So spheroidization process can reduce the hazardous of Ammonium dinitramide and improve the safe character of Ammonium dinitramide.

The nitration reaction is one kind of important reaction in many synthetic chemical reactions. The reaction with a high temperature releases a lot of heat and is easy to get out of control. The energetic materials is the main ingredients of the reaction mixture in late of nitrification of energy-containing materials, the accident about burn or rapid energy release will happen once the reaction is out of hand. There are so many thermal safety studies of energy materials, but the thermal safety research about energy material nitrification production line is not reported. Using the designed multi-scale energy material test, the thermal stability of DINA (N-Nitro-dihydroxyethylami) nitration reaction mixture was studied. The critical ignition temperature about different scale was obtained, and this temperature can be used as the base of enterprise process safety design.

With the rapid development of electronic devices, it is urgent to design and fabricate lightweight and effective electromagnetic absorption materials. Here, the graphene nanosheets/carbon nanotube/poly(vinylidene fluoride) (GNS/CNT/PVDF) composites with three-dimensional interconnected hierarchically porous networks have been successfully prepared via a facile solution mixing and followed by phase inversion method. The specific hierarchically porous structure in the composites possesses interconnected pores with various sizes. The open micro-scale pores on the top side give much smaller permittivity, which makes it less resistive to the incident microwave in a wide frequency range and is advantageous for multiple reflection and scattering of electromagnetic waves (EMW). The relatively smooth and dense bottom prevents EMW passing through the composites, which endows the prepared composites with a high EMW absorption. The as-prepared porous composites with 3.5 mm thickness exhibit a maximum absorption value of as high as − 32.7 dB at 11.50 GHz and display an ultra-wide efficient absorption bandwidth (entire X-band). Therefore, our work sheds light on a feasible strategy for designing and fabricating high-efficient EMW absorption materials.

Graphene has attracted considerable attention due to the distinguished thermal property to efficiently enhance the thermal transport of polymers. However, high interface thermal resistance (ITR) makes the actual enhancement efficiency of thermal conductivity for graphene/polymer composites below the predicted value. Herein, we proposed to pre-construct the three-dimensional (3D) thermal network in polymer matrix to efficiently reduce the ITR. The electropositive cetyltrimethylammonium bromide (CTAB)-functionalized graphene and the electronegative polydopamine (PDA)-functionalized MWCNT self-assembled to form an interconnected hybrid (CTAB–graphene@PDA–MWCNT) foam with vertical orientation via the directional freezing method. This unique structure provides a shortcut for phonon transmission and endows the obtained composite with the maximum thermal conductivity of 30.09 Wm−1 K−1 at 9 vol% filler contents. More importantly, PDA at the interface effectively hinders the electron transmission between fillers, resulting in moderate insulation of the prepared composite. (The volume resistivity is 3.2 × 106 Ω cm.) This demonstrates the prepared composite displays a promising prospect to tackle thermal management problems in modern electronics.

A facile esterification and electrospinning method is utilized to convert the waste lignin into nitrogen-oxygen co-doped esterified lignin/polyacrylonitrile based carbon nanofibers (E-CNFs). The analysis of FTIR and H1-NMR shows that the esterification reaction occurs between the hydroxyl group and the anhydride group and the ester bond is established in precursor. The lignin after esterification has lower glass transition temperature (Tg), and hence the obtained E-CNFs exhibit inter-fiber bonding structure, higher heteroatom content, and better wettability, rendering an efficient electron transport network and contributing pseudo capacitance. Such unique structure and morphology endow E-CNFs electrode with ultra-high specific capacitance of 320 F g−1 at 1 A g−1 and 200.4 F g−1 at 20 A g−1 with 6 M KOH aqueous as electrolyte, revealing outstanding rate capability. Moreover, the assembled E-CNFs//E-CNFs symmetric supercapacitors using 1 M Na2SO4 aqueous as electrolyte deliver a high coulombic efficiency of 112.5% at the current density 1 A g−1, a remarkable energy density of 17.92 Wh kg−1 at the power density of 800 W kg−1, and excellent cycling stability (∼5.5% loss after 5000 cycles). This inter-fiber bonding structure control strategy provides a perspective and avenue for the further development of high-performance electrode material for supercapacitors applications.

A two-dimensional carbon-based composite material loaded with magnetic nanoparticles Fe3C (CN–Fe3C) was successfully designed and prepared to ensure the dielectric loss and magnetic loss effect occur simultaneously. The impedance matching of the material is better realized, and the absorbing performance is improved. The loading of ferromagnetic Fe3C effectively improves the magnetic properties of the composites. When the filling amount is only 10 wt%, the composite can achieve a reflection loss value of −46.78 dB at 13.53 GHz, and the effective absorption bandwidth is as high as 5.01 GHz. The excellent absorbing performance is mainly due to the enhancement of interfacial polarization and the synergistic effect between the dielectric properties of carbon materials and the magnetic properties of Fe3C. CN–Fe3C/PVDF also shows good electromagnetic shielding effectiveness. This work has developed new ideas for designing and preparing “thin”, “light”, “wide”, and “strong” two-dimensional carbon-based composite absorbing materials.

The pressure sensor with high sensitivity and a broad pressure sensing range is highly desired for flexible electronics. Here, a high-performance pressure sensor based on a hybrid structure was facilely fabricated using the glass template method, which consists of polyurethane (PU) mesodomes embedded with gradient-distributed silver nanowire (AgNW). Such a novel hybrid architecture enables the as-prepared PU/AgNW pressure sensor to have high sensitivity as well as a wide detection range. Moreover, the obtained PU/AgNW pressure sensors have a fast response time (20 ms), good cycling stability, and excellent flexibility. The pressure sensor, benefiting from its outstanding comprehensive sensing performance, can be used for expression recognition and human activity monitoring, showing tremendous application potential in wearable devices. The proposed architecture and developed methodology in this work is promising for future flexible electronic applications.

Eco-friendly graphene oxide (GO)/waste-newspaper cellulose (WCE) and graphene nanosheet (GNS)/WCE composite aerogels were facilely synthesized via the sol–gel and freeze-drying processes. Morphological analysis and structural characterization revealed that the prepared composite aerogels possessed the perfect foam structure. Due to the different interactions between the aerogel and dyes, namely, electrostatic attraction, charge repulsion, and π–π interaction, the composite aerogels exhibited significantly discrepant adsorption capacities for two dyes, namely, methylene blue (MB, cationic) and Congo red (CR, anionic). With the addition of 0.5 w/v% GO, the MB adsorption capacity of WCE obviously improved by 235.6% from 65.4 to 154.1 μmol g−1, while the CR adsorption only increased by 70.2%. On the contrary, the CR adsorption of GNS/WCE was distinctly superior to that of MB. Furthermore, the entire adsorption process was suitable to be modeled by Langmuir isotherm, pseudo-second-order kinetics model, and intraparticle diffusion mechanism. These findings provide guidance for the development of green and efficient adsorbents for the removal of dyes from wastewater.

Flexible strain sensors have attracted a great amount of attention for promising applications in next-generation artificially intelligent devices. However, it is difficult for conventional planar strain sensors to meet the requirements of miniature size and light weight for flexible electronics. Herein, a highly sensitive and stretchable fiber strain sensor with a millimeter diameter was innovatively fabricated by the capillary tube method to integrate silver nanowires (AgNWs) in polyurethane (PU) fibers. Scanning electron microscopy results demonstrate that AgNWs were embedded into the surface layer of PU fibers and formed completely conductive networks. The unique AgNW networks endow the PU/AgNW fibers with superior electrical conductivity of 3.1 S/cm, high elongation at break of 265%, wide response range of 43%, high gauge factor of 87.6 up to 22% strain, fast response time of 49 ms, and excellent reliability and stability. Such satisfactory stretchability and sensitivity is attributed to the combination of the highly stretchable PU matrix and the embedded architecture of the AgNW conductive network. Moreover, PU/AgNW fibers can be employed as wearable devices to detect various human motions and to drive light-emitting diodes at a lower voltage (2.7 V).

Flotation is often employed to separate valuable natural minerals and gangue minerals. However, few studies have been conducted on artificial mineral flotation. Anosovite, the primary mineral in titanium slag, is a typical artificial mineral that can be enriched by flotation. In the present work, flotation behavior and adsorption mechanism of anosovite in salicylhydroxamic acid (SHA) solution were studied. The influence of pH and SHA dosage on anosovite flotability was investigated. Micro-flotation test results show that a pH range of 7–8.5 is available for SHA to collect anosovite. A maximum recovery of 93.26% can be obtained with SHA dosage of only 4×10−5 mol/L. In addition, TOC, zeta potential, FTIR, SEM-EDS, and XPS analyses were used to study the adsorption mechanism. Results demonstrated that SHA adsorption is governed by chemisorption. XPS studies further suggested that chemical adsorption occurred at the Ti sites on the anosovite surface.

Electrically conductive segregated networks were formed in carbon nanotube (CNT)/poly(lactic acid) (PLA) composite, in which CNTs are selectively located in poly(l-lactide) (PLLA) continuous phase and the continuous phase forms completed conductive networks at PLA stereocomplex crystallites (PLAsc) domain interfaces. The segregated CNT/PLLA/PLAsc composite with only 2.0 wt % CNT already exhibits an average electromagnetic interference (EMI) shielding effectiveness (SE) of 36 dB, which is 90% higher than that for the conventional CNT/PLLA composite with the same CNT loading. Owing to the high interfacial adhesion between PLLA and PLAsc, the tensile strength of the CNT/PLA composite reaches 65.2 MPa, which is 52% higher than the 41.8 MPa measured for pure PLAsc. Our work provides a novel way to develop a CNT/PLA composite with simultaneous high-performance EMI shielding and superior mechanical properties.

Reduced graphene oxide (rGO)/Ni hybrids with different mass ratio are successful synthesized in order to tune the microwave absorption together with the electromagnetic shielding performance. By properly adjusting the permittivity and permeability derived from different contents of the rGO and Ni, an rGO/Ni composite with excellent microwave absorption properties is obtained. An optimal reflection loss value of −39.03 dB at 13 GHz is achieved for the composite with rGO/Ni ratio of 1:1, and the bandwidth less than −10 dB can reach up to 4.3 GHz (from 11 to 15.3 GHz) with a thickness of 2.0 mm. Furthermore, the composite with rGO/Ni ratio of 4:1 shows superior electromagnetic shielding performance as high as 52 dB, which far surpasses the best value for most carbon-based materials. Fundamental mechanisms for absorbing and shielding performance are discussed.

To effectively and selectively remove toxic anionic dyes which are heavily discharged and to promote them recovery, a sustainable cellulose nanofiber/chitosan (CNF/CS) composite film was elaborately designed through a facile procedure. Based on the strong supporting effect of CNF and excellent compatibility between CNF and CS, the composite film presents low swelling and acid-proof properties, which can prevent the adsorption process from the disintegration of adsorbent. Moreover, the positive electrical property of CNF/CS film increases the discrepancy in adsorption capacities for anionic and cationic dyes. The maximum adsorption capacity of anionic methyl orange (MO) on CNF/CS film reaches 655.23 mg/g with a desirable recyclability. The adsorption behavior attributed to a physico-chemical and monolayer adsorption process. This work opens a new route for the development of eco-friendly and highly efficient adsorbents on selective removal and recycling of anionic dyes from wastewater.

High Fischer ratio oligopeptides have better conditioning effects on chronic diseases caused by long-term sub-health. At present, the enzymatic method for producing high Fischer ratio oligopeptides has a low yield, complicated purification, and a high cost. The use of exopeptidases with specific catalytic activity for aromatic amino acids in the preparation of high Fischer ratio oligopeptides is an important means to solve this problem. The carboxypeptidase from Aspergillus niger M00988 was cloned, which has good specificity for hydrophobic amino acids. Mutations at important substrate binding sites 135, 160, and 206 were performed to study important factors affecting the enzyme-specific recognition of aromatic groups. The results showed that the steric hindrance of amino acid residues at position 135 and the effects of positions 160 and 206 on the binding force of the enzyme to the substrate have important effects on the specific recognition of aromatic groups by the enzyme. Therefore, the S135 G, Y160S, and Y206S mutant enzymes have good application prospects in the preparation of high Fischer ratio oligopeptides with Chlorella powder. The obtained oligopeptides’ Fischer ratio reached 31.45, 38.42, and 36.54, respectively. Compared with the original enzyme, the Fischer ratio increased by 2.58 %, 25.31 %, and 19.18 %, respectively.

Thermal management has developed into a severe issue with the evolution of electronics. The construction of effectively thermal conduction pathways in the matrix is crucial for highly thermal conductive composites. In this work, a unique thermal conductive channel in the epoxy matrix had been established with hybridizing hexagonal boron nitride (BN) sheets and aluminum nitride (AlN) particles through a solution mixture and hot-pressing method. Synergetic enhancement of thermal conductivity was observed between BN and AlN fillers owing to the better dispersion of hybrid fillers, which created more pathways for phonon transport. With 40 vol% hybrid BN-AlN filler contents, the thermal conductivity of EP composite reached 2.4 Wm−1 K−1, eightfold increasing over the pristine epoxy matrix and two times to that of single BN or AlN filling composite. Moreover, the thermal conductivity of hybrid composite was further improved by more than 10% through the surface treatment of fillers with silane couple agents owing to the enhancement of interaction in composites. This study is of critical importance for composites used in electronics and electric equipment.

The hydrophobic TiO2/lignin based carbon nanofibers (TiO2@CFs) composite with high photocatalytic efficiency and excellent cycle performance is successfully prepared by the method of electrospinning and thermo-treatment. The results of FTIR, SEM and EDS analyses show that the TiO2 nano-particles are uniformly and firmly coated on the surface of CFs. Due to good hydrophobicity and high electrical conductivity of CFs, such unique properties endow TiO2@CFs composites with enhanced light energy utilization efficiency and photocatalytic efficiency because of their floatability on the solution, high adsorptive capacity of MB, and low recombination of photo-generated electrons and holes. Compared with the commercial TiO2 powder, the degradation rate toward MB of TiO2@CFs is improved about 2.62 and 3.02 times at 30 and 15 min, respectively, under static state and xenon lamp irradiation. The degradation rate of TiO2@CFs toward MB reaches 62.77% within 15 min under static state, and further increase to 87.28% after 30 min. In addition, the removal rate of MB can be obtained up to 91.5% even after four cycles at a stirring speed of 200 RPM. Therefore, these unique material structures make it become a promising photocatalytic material.

Purpose This study investigated the influence of inter-domain interactions on the substrate affinity and hydrolysis product specificity of xylanase. Methods Genes encoding a GH10 endo-xylanase from Streptomyces chartreusis L1105 xynA and its truncated derivative were cloned and expressed in Escherichia coli. The catalytic activities of the enzyme (xynA) and the derivative xynADCBM, lacking the carbohydrate binding module (CBM), were assessed to evaluate the role of CBM in xynA. Results Recombinant xynA (44 kDa) was found to be optimally active on beechwood xylan at 65 °C with pH 7.7, while xynADCBM (34 kDa) exhibited optimal activity at 65 °C with pH 7.2. Additionally, xynA and xynADCBM were found to be highly thermostable at 40–60 °C, each retaining 80% of their original activity after 30 min. The xynADCBM without the CBM domain was highly efficient at hydrolyzing xylan to produce xylobiose (over 67%), which may be because the CBM domain facilitates substrate binding with xylanase. Meanwhile, the xylan hydrolysis efficiency of xynADCBM was higher than that of xynA. Conclusion These findings showed that the CBM domain with non-catalytic activity has no significant effect on the characteristics of the enzyme at optimum pH and pH tolerance. It has also been suggested that the derivative xynADCBM without CBM components can promote hydrolysis of xylan to yield xylooligosaccharides, which has great potential economic benefits.

The mycotoxin Ochratoxin A (OTA) causes serious health risks and is found in food products throughout the world. The most promising method to detoxify this compound is biodegradation. In this study, Aspergillus oryzae strain M30011 was isolated and characterized based on its considerable capacity to degrade OTA. The degradation product (compound I) of A. oryzae-treated OTA was isolated, and its toxicity response was also evaluated. Furthermore, the relationships between three key cultivation condition factors affecting the OTA degradation rate were examined using the response surface methodology (RSM). Compound I was identified as ochratoxin α (C11H9O5Cl), and the toxicity response experiments indicated that A. oryzae detoxified OTA to a great extent. A maximum degradation rate of 94% was observed after 72h. This study demonstrates the potential for using A. oryzae to detoxify OTA and suggests that it could be applied in the food industry to improve food safety and quality.

Conductive polymer composite with segregated structure has been well demonstrated to achieve high electromagnetic interference shielding effectiveness (EMI SE) due to the selectively distributed electrical nanofillers to establish desirable conductive networks. Nevertheless, the formation of segregated structure in low-melt-viscosity semi-crystalline polymer is still challenged and the segregated composite always suffers poor mechanical performance. Herein, elevated pressure and temperature were utilized to make a typical semi-crystalline polymer, polypropylene (PP), hold solid phase to restrict the diffusion of carbon nanotube (CNT) into its interior. Segregated CNT networks were facilely constructed in the resultant CNT/PP composite and imparted it with a superior EMI SE of 48.3 dB at 2.2 mm thickness and 5.0 wt% CNT loading, the highest EMI shielding level among the reported CNT/polymer composites at equivalent material thickness and CNT loading. Moreover, the elevated pressure and temperature effect dramatically increase the compressive, tensile, and flexural strength (modulus) of the CNT/PP composite by 133% (65%), 74% (130%) and 53% (50%), respectively, in comparison to those for conventional segregated CNT/PP composite, really overcoming the major mechanical shortcoming in the development of segregated composites for EMI shielding. Our work provides a facile strategy to fabricate the efficient EMI shielding and robust material with the construction of typical segregated structure in low-melt-viscosity semi-crystalline polymers.

Carbon nanotube/high density polyethylene (CNT/HDPE) foam composites with high electrical conductivity and electromagnetic interference (EMI) shielding performance were developed by means of compression molding plus salt-leaching. The uniform porous structure and interconnected CNT networks throughout the cell backbones endowed the as-prepared foam composites with a significantly lower electrical percolation threshold (0.22 vol%) than that of the solid composites (0.84 vol%). Owing to the multiple reflections and scattering between the cell–matrix interfaces, the foam composites presented a superior specific EMI shielding effectiveness (EMI SE) of 104.3 dB cm3 g−1, 2.2 times higher than that of their solid counterpart. Besides this, the pore sizes of the CNT/HDPE foam composites could be easily tuned by controlling the particle size of the porogen. Also, the electrical conductivity and specific EMI SE increased with an increase in the cell diameter, which was attributed to the formation of a more perfect conductive network in the cell backbones. Our approach provides a novel idea for fabricating new lightweight EMI shielding materials, especially for aircraft and spacecraft applications.

The simulated experiment of A. parasiticus isolated from the paddy was carried out during the paddy storage for 20 days. The growth and mycotoxin data were collected for constructing kinetic and probability models of moulds. The Baranyi and Gompertz model was employed as the primary model and estimated the lag phase and maximum specific growth rate. Secondary models, such as polynomial, Davey and Gibson model were used and completely evaluated under different conditions. The polynomial equation was highly rated compared with Gibson and Davey model and gave realistic temperatures and aw for mould growth. Logistic model showed promising results on the prediction of growth boundary and AFB1 production. Employed models showed promising predicted results, indicating that it is an effective tool for describing and predicting the growth of moulds under different temperatures and aw. The results can be applied to develop the optimal strategy to prevent fungal spoilage and aflatoxin production during paddy storage.

In recent years, biomass-derived carbon electrode materials for energy storage have attracted intensive attention in terms of their natural unique structure, widespread availability and low cost. Herein, a unique hierarchical porous carbon composite material (CGCM@GNS&CNT) was facilely constructed on 3-D carbon skeleton by anchoring 2-D graphene nanosheet (GNS) and 1-D carbon nanotube (CNT) through self-assembling method. The CGs with abundant macroscopic pores were utilized as 3D carbon skeleton, CNT and GNS anchored on them were applied to enhance the specific surface area (SSA) and electrical conductivity. The composite material exhibits large SSA of 460 m2 g−1, interconnected conductive network and inherent N, O doping. The CGCM@GNS&CNT electrode achieves a high areal capacitance of 441 mF cm−2 and volumetric capacitance of 90 F cm−3 at 1 mA cm−2 in 1.5 M Na2SO4 electrolyte. More importantly, the CGCM@GNS&CNT-based symmetric supercapacitor affords a remarkable energy density of 31 μWh cm−2 at a power density of 800 μW cm−2 in 1.5 M Na2SO4. The capacitance retention and coulombic efficiency can retain 102.5% and 100.5% over 2000 cycles, respectively, confirming its superb charge/discharge stability and long-term reversibility. These signify that CGCM@GNS&CNT material holds a considerable promise for electrode application in high-performance supercapacitor.

Graphene oxide nanosheets coated with magnetic ferroferric oxide nano-particles (Fe3O4@GO) were firstly in-situ synthesized and then employed as fillers to prepare a polyvinyl alcohol (PVA) nanocomposite film with ultrahigh gas barrier property under magnetic field. Fourier-transform infrared spectroscopy (FTIR) and Transmission Electron Microscope (TEM) showed that the magnetic Fe3O4 particles were homogenously absorbed onto the surface of GO sheets. Polarizing optical microscopy (POM) and Scanning Electron Microscopy (SEM) results proved that the PVA composite film containing congregated and oriented Fe3O4@GO nanosheets was facilely manufactured aided by the magnetic field. Due to dramatic decline of gas permeable areas along parallel direction of film, an unprecedented improvement on gas barrier property of PVA/Fe3O4@GO nanocomposite film was achieved. With the addition of only 0.072 vol% Fe3O4@GO, the oxygen permeability (PO2) of PVA film decreased from 21.17 × 10−15 to 0.2126 × 10−15 cm3 cm/(cm2 s Pa), showing about 99.0% improvement of gas barrier performance. The modified Bharadwaj model introduces a proportionality coefficient (k), giving better prediction of the PO2 of PVA/Fe3O4@GO nanocomposites. In addition, the prepared PVA/Fe3O4@GO nanocomposite film exhibited excellent tensile strength and Young’s modulus. This congregated and oriented nanocomposite film with unprecedentedly excellent barrier performance could be perceived as a satisfying alternative for the traditional aluminum films applied in food and medicine packaging.

Poly-(butylene adipate-co-terephthalate) (PBAT) has captured significant interest by dint of its biodegradability, superb ductility, promising processing properties and good final properties, but the insufficient barrier performance limits its application, especially in packaging field. In the present work, improved barrier properties of PBAT films were obtained by introducing an extremely low amount of graphene oxide nanosheets (GONS). O2 and water vapor permeability coefficients were decreased by more than 70% and 36% at the GONS loading of 0.35 vol%, respectively. The enhanced barrier performance was ascribed to the outstanding impermeability and well dispersion of GONS as well as the strong interfacial adhesion between GONS and PBAT matrix. Furthermore, tensile strength and Young's modulus of GONS/PBAT nanocomposite rise up to 27.8 MPa and 72.2 MPa from 24.6 MPa to 58.5 MPa of neat PBAT, respectively, showing a prominent increase of mechanical properties compared to neat PBAT. The incorporation of GONS also endowed PBAT matrix with an excellent thermal stability. These findings provide a significant guidance for fabricating high barrier films on a large scale.

Effect of air drying and freeze drying on polysaccharides of lychee with three cultivars was determined in terms of polysaccharides yield, antioxidant capacity and hypoglycemic action. The results show that Guiwei lychee pulp had the highest crude polysaccharide yield among three lychees. However, Feizixiao lychee had the lowest EC50 concentration and the highest FRAP (Ferric reducing antioxidant power) value. Moreover, Guiwei lychees dried by air drying had the best effect for improving glucose tolerance of normal mice and diabetic mice. Three freeze dried lychees had no significant effect. The effect of air dried Guiwei samples on decreasing TG was the best and it was even better than dapagliflozin group. Only freeze-dried Guiwei lychee could significant decrease the TC content in blood among all lychee samples. In a word, Feizixiao lychees had the best antioxidant capacity and Guiwei lychees had the best hypoglycemic effect. Air drying was better drying method for lychee polysaccharides than fr...

In this work, a simple and cost-effective method is proposed to prepare iPP films with high barrier properties. By adding a very small amount of β-nucleating agent, three types of β-crystal morphologies, namely, β-spherulites, β-transcrystals and β-“flower”-like agglomerates are sequentially obtained in iPP with the increasing processing temperature. Among β-nucleated iPP films, the one with β-“flower”-like agglomerates demonstrates the best water vapor and oxygen barrier performances, whose water permeability coefficient is decreased by 50.3% and oxygen permeability coefficient by 67.5%, compared to pure iPP films. Refined crystals, sufficient connection within the crystallites and lamellae parallel to the gas flow direction in iPP with β-“flower”-like agglomerates may force the gas molecules to take longer and more tortuous pathway, thus resulting in excellent barrier properties. Our work provides a new idea to prepare iPP films with high barrier properties by simply manipulating their crystal morphology.

The segregated graphene oxide(GO)/ultra-high-molecular-weight polyethylene (UHMWPE) composite films with various interfacial adhesion property were prepared by mechanical blending method from UHMWPE, GO, dodecyl amine (DA) functionalized graphene oxide(DA–GO) or uniform DA–GO/high density polyethylene (DA–GO/HDPE) powder. The results of XRD and XPS indicated that DA chain was successfully grafted onto GO sheets via a chemical method, which enhanced the interfacial adhesion between UHMWPE particles and GO sheets. The characterizations of POM and SEM proved that good segregated structure was only obtained in DA–GO/UHMWPE or DA–GO/HDPE/UHMWPE composite. Strong interfacial adhesion between fillers and matrix exhibits positive effect on gas barrier property. Compared to the GO/UHMWPE composite film, dramatic decrease in O2 permeability coefficient by 42.2 and 48.1%, from 15.4 × 10−14 to 8.9 × 10−14 and 8.0 × 10−14 cm3 cm cm−2 s−1 Pa−1, is achieved upon the addition of only 0.5 wt% fillers, respectively...

Various ultra-high-molecular-weight polyethylene (UHMWPE)/boron nitride (BN) and UHMWPE/(BN + multi-wall carbon nanotube (MWCNT)) composites with segregated structure were prepared by using the compression molding process. The dispersion of fillers under different compression molding were observed by optical microscopy and scanning electron microscopy. The results showed that integrated thermal conductive networks were formed after cold-pressing sintering. However, these networks would be destroyed by middle-high pressure/high temperature treatment. Although the treatment of high pressure/high temperature can effectively improve the crystallinity and crystal size of UHMWPE, the thermal conductivity of composite dramatically decreased due to the replacement of filler-filler by filler-polymer-filler interface. The 1D-MWCNT is liable to entangle with 2D-BNs and formed MWCNT-BN networks even at high pressure/high temperature, leading to a nearly constant thermal conductivity (reached 1.794 W/m·K with the addition of 50% (BNs + MWCNT) hybrid fillers). Besides, the dispersion of the fillers have a great influence on thermal stability of the composites.

Polypropylene random co-polymer (PPR)/styrene-ethylene-butylene-styrene (SBS) block copolymer blends with high toughness and favorable tensile properties were successfully obtained by blending with traces of multi-wall carbon nanotubes (MWCNTs) and &beta, nucleating agents (&beta, NAs). &beta, NAs can effectively induce the ductile &beta, form crystal in the PPR matrix. Although the addition of MWCNTs was reported to be only benefit for the tensile strength of PPR and relatively disadvantageous for the toughness, the obviously synergistic toughening effect in PPR/SBS blends was found when MWCNTs and &beta, NAs coexisted. The notched izod impact strength of PPR/30 wt % SBS blend with MWCNTs and &beta, NAs increased from 11.3 to 58.9 kJ/m2, more than 5-fold increment compared with pure PPR. Meanwhile, the tensile strength retention of this PPR blend is still above 72.2%. The micro-morphology indicated that the MWCNTs can act as bridges between SBS particle and PPR matrix, effectively transferring the stress and absorbing impact energy among SBS particles.

Titanium dioxide (TiO2) is considered a promising photocatalyst due to its remarkable properties, such as photostability, low energy consumption and non-toxicity. However, some intrinsic drawbacks of TiO2 including high band gap energy and easy recombination of electron-hole pairs seriously hinder its practical application in photocatalysis. In this study, a 1-nm-thick carbon coating layer was introduced onto the surface of TiO2 (TiO2@C) by carbonizing kraft lignin to improve the photocatalytic performance. Compared with TiO2, TiO2@C shows absorption in both visible-light and UV-light regions, a decrease in band gap energy from 3.31 to 3.27 eV and excellent electronic conductivity, which favour the generation and separation of photo-generated carriers. In addition, the ultra-thin carbon coating can guarantee the penetration of sunlight, and TiO2@C, which remains afloat on the water, can contact with wastewater and absorb sufficient sunlight due to the hydrophobicity and loose structure. The investigation of photocatalytic degradation towards methylene blue (MB) and tetracycline (TC) under artificial visible-light irradiation demonstrates that the prepared TiO2@C has relatively superior photocatalytic activity. The absorbed MB and TC are almost completely degraded by TiO2@C within 10 min and 35 min, respectively. Given the simple modification and excellent photocatalysis, the prepared TiO2@C exhibits great potential applications in contaminated water treatment. This study provides a feasible carbon-coating strategy to improve the photocatalytic performance of TiO2, which can be extended to the rational design of other photocatalysts.

In this work, nitrogen (N), sulfur (S) co-doped porous carbon nanoplate (A-MBCP) is successfully prepared from methylene blue (MB) by facile one-step carbonization and activation strategy. It is an efficient method to protect the environment and meet industrialization production. The obtained carbon nanoplate exhibits in-situ doping of N, S, high specific surface area (560.46 m2 g−1), interconnected and hierarchical porous morphology, together with large interlayer spacing. This unique and complex micromorphology endows the A-MBCP electrode with superior electrochemical performance, including ultra-high specific capacitance of 302 F g−1 at 0.5 A g−1 and excellent capacitance retention of 77.82% at 10 A g−1 in 6 M KOH electrolyte. Furthermore, the assembled A-MBCP//A-MBCP symmetric supercapacitor displays outstanding energy density of 25 Wh kg−1 and power density of 8000 W kg−1 using Na2SO4 as electrolyte. Also, the high capacitance retention of 98.6% and coulombic efficiency of 97.9% are achieved for the supercapacitor after 3000 cycles at 2 A g−1 in KOH electrolyte, implying its favorable electrochemical stability and charge/discharge reversibility. This novel preparation of high-performance supercapacitors from MB may further inspire the development of other carbon materials with heteroatoms doping applied in the energy storage application.

Poly(lactic acid) (PLA), a promising sustainable packaging material, suffers from intrinsic poor gas barrier performance partly due to its innate defect of relatively low crystallization rate. In the present study, taking advantage of the excellent impermeability and heterogeneous nucleating ability of graphene oxide nanosheets (GONSs), the crystalline structure of PLA nanocomposite film was manipulated using processing techniques. We revealed that GONSs were the α-nucleating agent for PLA, inducing typical spherulite morphology. More interestingly, two-dimensional small-angle scattering characterization confirmed that GONSs were preferentially dispersed in the amorphous phase between PLA spherulites, achieving a concentrated GONS region. As a consequence, the “composite barrier wall” consisting of concentrated GONSs and impermeable PLA lamellae gave rise to O2 permeability of PLA nanocomposite film at a GONS loading of 1.0 wt % as low as 0.211 × 10–14 cm3 cm cm–2 s–1 Pa–1, reduced by ∼89.9% relative to n...

The low-temperature catalytic oxidation of heavy crude oil (Xinjiang Oilfield, China) was studied using three types of catalysts including oil-soluble, water-soluble, and dispersed catalysts. According to primary screening, oil-soluble catalysts, copper naphthenate and manganese naphthenate, are more attractive, and were selected to further investigate their catalytic performance in in situ upgrading of heavy oil. The heavy oil compositions and molecular structures were characterized by column chromatography, elemental analysis, and Fourier transform infrared spectrometry before and after reaction. An Arrhenius kinetics model was introduced to calculate the rheological activation energy of heavy oil from the viscosity–temperature characteristics. Results show that the two oil-soluble catalysts can crack part of heavy components into light components, decrease the heteroatom content, and achieve the transition of reaction mode from oxygen addition to bond scission. The calculated rheological activation energy of heavy oil from the fitted Arrhenius model is consistent with physical properties of heavy oil (oil viscosity and contents of heavy fractions). It is found that the temperature, oil composition, and internal molecular structures are the main factors affecting its flow ability. Oil-soluble catalyst-assisted air injection or air huff-n-puff injection is a promising in situ catalytic upgrading method for improving heavy oil recovery.

In this work, the effects of oxygen concentration and reservoir cutting on thermokinetic characteristics of light oil were analyzed using thermogravimetry (TG/DTG). Results show that three consecutive oxidation reactions of distinct chemical mechanism (low-temperature oxidation [LTO], fuel deposition [FD], and high-temperature oxidation) are detected for all tested samples. Hypoxic air weakens the LTO and FD process and causes a poor FD performance, while reservoir cutting positively influences the thermal characteristics of oil. Kinetic parameters comparison exhibits that the positive effect of reservoir cutting on oil oxidation is significantly stronger than the negative impact caused by hypoxic air. The existence of reservoir cutting greatly reduces the activation energy of oil oxidation in hypoxic air environment, which is a positive signal for the implementation of high-pressure hypoxic air injection process.

In this work, the low-temperature oxidation (LTO) characteristics of different API gravity crude oils, involving one light, one medium, and one heavy, are studied comprehensively from the aspects of effluent gas, oxidized oil, and pressure drop. The results reveal that heavy oil exhibits faster LTO reaction rate and stronger O2 consumption capability compared with lighter ones. There are a certain amount of carbonaceous deposits in oxidized oils and the carbonation progress of heavy oil is brought to a deeper degree. The pressure drop rule of oil samples is speculated to be the consequence of “skin effect” and crude oil with more heavy species shows higher oxidation activity, which contributes to an improved understanding about the LTO mechanism from the molecular perspective and needs further research.

In this nonisothermal research, the thermal behavior and oxidation kinetics of crude oils were investigated through TG/DTG and DTA tests at three heating rates. The resulting curves exhibit three integrated reactions of distinct oxidation mechanisms (LTO, FD, and HTO) sequentially in overlapped temperature intervals as reaction progresses, the behaviors of that are affected greatly by heating rate. Because of the larger amounts of heavy components and higher availability of deposited fuel, heavy oil exhibits more excellent heat release capability but higher kinetic parameters than light oil, especially in HTO region. Due to the insufficient parameters calculation based on a single kinetic method, other formulated models would be introduced for comparative analysis in the next work to upgrade kinetic research.

In this study, graphene oxide reinforced regenerated cellulose/polyvinyl alcohol (GO-RCE/PVA) ternary hydrogels were successfully prepared via a repeated freezing and thawing method in NaOH/urea aqueous solution. The effect of GO content on the mechanical properties, swelling behavior, water content of composite hydrogels was investigated. It was found that the mechanical properties of GO-RCE/PVA ternary hydrogels were largely enhanced relative to RCE/PVA hydrogels. With the addition of 1.0wt% GO, the tensile strength was increased by 40.4% from 0.52MPa to 0.73MPa, accompanied by the increase of the elongation at break (from 103% to 238%). Meanwhile, GO-RCE/PVA ternary hydrogels performed the excellent pH-sensitivity, and the higher pH leaded to higher swelling ratio. With 0.8wt% GO loading, the swelling ratio of GO-RCE/PVA ternary hydrogel was improved from 150% (pH=2) to 310% (pH=14). In addition, a slight increase in the water content of the ternary hydrogel was achieved with increasing concentrations of GO. It is believed that this novel ternary hydrogels is a promising material in the application of biomedical engineering and intelligent devices.

In this research, the catalytic effect of four types of clays on crude oil low-temperature oxidation was analyzed in depth via static oxidation tube experiments and DTG-DTA tests. Results show that the LTO reactions are positively brought to a deeper degree by clays through lowering the energy requirement for the oxidation/cracking reactions, accelerating reaction rates, and depositing more coke-like fuel. All samples exhibit endothermic oxidation behavior and their energy requirements are proportional to mass loss rates. Based on catalytic study on the oxidation and thermokinetic behaviors of crude oil, a high degree of consistency is discovered between the two types of thermal analysis methods.

In this study, the effect of heating rate, oil chemical composition, and clay mineral type on thermokinetic behaviors of oil oxidation was investigated by TG and DTA tests. The results show that temperature intervals of reactions are extended and peak and burnout temperatures are shifted to higher values when increasing the heating rate. Heavier oil with more heavy components exhibits faster reaction rate and higher energy requirement in the low-temperature oxidation stage, and releases more heat in the high-temperature oxidation stage. The catalytic properties and surface area effect of clays can positively influence the high-pressure air injection process through forming more carbonaceous deposits and lowering the activation energy of reactions.

Based on a rigid ligand, 2,5-bis[3'-carboxyl-phenyl] pyridine (H2L), two coordination polymers (CPs) formulated as Cd3L3(DMF)4 (1) and CdL(DMF)·DMF (2) were solvothermally synthesized and characterized by single-crystal X-ray diffraction. CP 1 is a uninodal 6-connected 3D network with a {4(4)·6(10)·8}-mab topology, in which the Cd3 unit with a CdCd separation of 3.61 Å is observed. CP 2 exhibits a uninodal 2D layer with a 4(4)-sql topology, in which Cd(ii) ions are linked into a Cd-O-Cd chain with a CdCd separation of 3.91 Å. DFT calculations indicate that CP 1 possesses a more narrow band gap than CP 2, and CP 1 yields higher photocurrent density upon visible light illumination than CP 2. In the present work, the few-layered CP 2 has been in situ synthesized, and it shows enhanced photocurrent density with respect to the bulk CP, which is probably associated with the large fraction of uncoordinated surface atoms and dangling bonds in the nanosheet of CP 2.

A flexible and multi-layered graphene nanosheets (GNSs)-Fe3O4/poly (vinylidene fluoride) hybrid composite film with high-efficient electromagnetic interference (EMI) shielding was fabricated via a facile layer-by-layer coating. The well-designed multi-layered and hybrid electromagnetic fillers endow the prepared film with good surface impedance matching and prominent internal multiple absorption, which forms “absorb-reflect-reabsorb” electromagnetic transmission pattern and results in highly efficient electromagnetic shielding effectiveness (EMI SE). The resultant composite film exhibits an exceptional EMI SE of 52.0 dB at a thickness of 0.3 mm. What is more important is that the prepared film exhibits excellent flexibility and EMI stability, and the retention rate of efficient EMI SE is high as 91.9% after 1000 bending-release cycles. This study provides a feasible strategy for designing high-efficient EMI shielding film with excellent flexibility and ultra-thin thickness that suitable for next-generation intelligent protection devices.