查找使用阿拉丁产品的科研文献

Novel hyperbranched poly(urethane–imide)s with enhanced thermal, mechanical, and UV-shielding properties

Jun Tian,Qing Li,Liji Xiao,Zushun Xu,Changfeng Yi

A series of novel hyperbranched poly(urethane–imide)s (HBPUIs) was synthesized and derived from as-prepared imide-containing glycol and commercial materials via an A2 + B2 + B3 approach. The chemical and morphological structures of the resulting polymers were evaluated by infrared attenuated total reflection and X-ray diffraction techniques, respectively. Compared with pure HBPU, HBPUIs exhibited better thermal stability with the 10% weight loss temperature of 282–298°C under nitrogen atmosphere, good mechanical property with the tensile strength of 2–19 MPa, and elongation at breaks of 461–896%. Moreover, optical transmissivity of all films was measured and the results showed that they had excellent transparency in the scope of visible light. Meanwhile, the cutoff wavelengths of as-prepared HBPUI films were at around 350 nm, which can block the whole ultraviolet (UV)-C (200–280 nm) and UV-B (280–320 nm), as well as a part of UV-A (320–400 nm). Furthermore, the designed photocatalytic degradation experiment of the methylene blue (MB) confirmed that HBPUI films had good UV-shielding performance with 70% degradation of MB after intense UV irradiation (400 W) for 50 min under the protection of HBPUI film with 14% imide-containing glycol. This endowed HBPUIs with potential applications prospect in UV-shielding materials.

Efficient photocatalytic hydrogen peroxide production over S-scheme In2S3/molten salt modified C3N5 heterojunction

Huagen Liang,Haoran Wang,Anhu Wang,Ruolin Cheng,Shengyu Jing,Fu Chen,Palanisamy Kannan,Georgia Balkourani,Panagiotis Tsiakaras

Graphitic phase carbon nitride (g-C 3 N 5 ), as a novel n -type metal-free material, is employed as a visible light-receptive catalyst because of its narrow band gap and abundant nitrogen. To overcome the low carrier mobility efficiency of g-C 3 N 5 , its modification by K ions was adopted. In addition, In 2 S 3 was selected to couple with modified g-C 3 N 5 to overcome the recombination of photogenerated e − /h + . As a novel photocatalytic material, it was proven to possess a high visible light absorption capacity and a strong H 2 O 2 production ability (up to 3.89 mmol⋅L -1 in 2 h). Moreover, a S-scheme heterojunction structure was successfully constructed between the two materials, which was tested and confirmed to be successful in raising the photogenerated e − /h + separation efficiency. Ultimately, the primary processes of photocatalytic H 2 O 2 production were summarized by superoxide radical and rotating disc electron measurements. This research provides a fresh perspective for the synthesis of C 3 N 5 -based S-scheme heterojunction photocatalysts for producing H 2 O 2 .

Enhanced Bone Targeting of Poly(l-glutamic acid)s through Cationic or Aromatic Substitution

Xiaoxiong Jin,Wanying Wang,Hui Liu,Jing Zhao,Pengfei Li,Aoting Li,Ziyuan Song

Poly(l-glutamic acid)s (PLGs) are promising bone-targeting ligands due to their high molecular weight and facile preparation. Nevertheless, the bone-targeting efficiency of PLGs is still relatively low, validating the necessity to further enhance targeting through structural optimization. Herein, we report the use of a heteropolypeptide strategy to improve the bone targeting of PLGs through the incorporation of another side-chain functionality for enhanced affinity with bone tissues. Specifically, the introduction of cationic amino or aromatic phenolic side-chain residues resulted in a ∼2.3-fold or ∼1.6-fold increase in the in vivo bone targeting, respectively. Cationic modification not only improved the affinity with bone minerals but also exhibited prolonged retention in the bone tissues for more than 60 days. This work highlights the use of a heteropolypeptide library to screen and optimize the performance of polypeptide materials, offering promising bone-targeting polymeric materials for the design of bone-related nanomedicine.

Boosted photocatalytic hydrogen evolution of S-scheme N-doped CeO2-δ@ZnIn2S4 heterostructure photocatalyst

Shumail Farhan,Asif Hassan Raza,Songyu Yang,Zhixian Yu,Yan Wu

The advancement of highly effective heterojunction photocatalysts with improved charge separation and transfer has become a crucial scientific perspective for utilizing solar energy. In this study, we developed the S-scheme heterostructure by depositing N-doped CeO 2-δ (NC) nanoparticles onto two-dimensional ZnIn 2 S 4 (ZIS) nanosheets via hydrolysis strategy for significantly enhanced photocatalytic hydrogen evolution reaction. The optimal H 2 generation rate of ∼ 798 μmol g –1 h –1 was achieved for NC-3@ZIS under solar light irradiation, which is about 18 and 2 times higher than those of pristine CeO 2 (∼44 μmol g –1 h –1 ) and ZIS (∼358 μmol g –1 h –1 ), respectively. The photogenerated electrons from NC interact with the photogenerated holes of ZIS driven by an internal electric field, confirmed by In-situ KPFM, DFT calculation, and XPS results. According to EPR and photoelectrochemical measurements, NC-3@ZIS composite shows dramatically high separation efficiency of photogenerated charge carriers. This study provides a new approach for developing non-noble metal S-scheme heterojunctions with enhanced photocatalytic hydrogen evolution.

A facile approach to the preparation of S-doped porous carbons for CO2 adsorption

Hongmin Cui,Jianguo Xu,Nanfu Yan,Runhan Yan,Jinsong Shi

In the current work, we explored the direct synthesis of S-doped porous carbons employing cesium methanesulfonate as a novel bifunctional chemical activator. The obtained carbons showed high surface area (654–2264 m 2 /g) and high S content (6.56–15.13 wt%). Effects of activation temperature and cesium methanesulfonate amount on the carbons’ properties were also studied. The obtained carbons showed CO 2 uptake of 3.58–4.76 mmol/g at 0 °C and 1 bar. Effects of textural properties and S-doping on CO 2 adsorption performances were discussed.

Ag-S coordination strategy for high recovery driving stress in recyclable shape memory polymers

Zhongzheng Zhu,Siyu Liu,Junyi Yao,Qitan Zheng,Yutong Guo,Yujie Chen,Hezhou Liu,Hua Li

To address the issue of low strength and recovery stress in recyclable shape memory polymer (SMP) materials with dynamic covalent bonds in practical applications, we propose a method based on Ag-S coordination interactions to improve dynamic covalent bonds, thereby preparing recyclable SMP with high recovery stress and large recovery strain. The introduction of in situ reduced silver nanoparticles (AgNPs) in the SMP system play multiple roles, serving as additional physical crosslinking points at the microscale and coordinating with disulfide bonds in the system to construct a multi-level dynamic network structure. This endows the material with exceptional mechanical properties (tensile strength of 25.93 MPa and fracture strain of 1466.83 %) and recovery driving stress (5.59 MPa), while maintaining more than 99 % shape recovery and fixity rate. Furthermore, due to the outstanding photothermal performance of AgNPs, the composite material has acquired remote photothermal driving capabilities. The proposed Ag-S coordination enhancement offers a new approach for SMP materials that achieve both large actuation distance and high recovery stress, holding significant potential for applications in soft robotics and actuators.

Immobilization of cellulases on the reversibly soluble polymer Eudragit S-100 for cotton treatment

Yuanyuan Yu,Jiugang Yuan,Qiang Wang,Xuerong Fan,Ping Wang,Xuejiao Sun

Cellulases can penetrate into the fiber, causing tensile strength loss of the cellulosic fibers or fabrics. To minimize the tensile strength loss, we have immobilized cellulases on Eudragit S-100. The characteristics of covalent Eudragit cellulase were evaluated using gel filtration analysis and UV spectra. Gel filtration analysis revealed that the cellulases were covalently bound to the polymer. Covalent Eudragit cellulase was loaded with the enzyme of about 40% and had a relative activity about 80% at a Eudragit S-100 concentration of 15 g/L. When cellulase is bound to the polymer, the solubility profile becomes similar to the one of Eudragit. In addition, the effects of the enzyme on the cotton yarns and fabric using cellulases have been investigated. Native and immobilized cellulases caused improvements in whiteness and wrinkle recovery angle of the fabric in comparison to the control samples. The bending stiffness results show that native and immobilized cellulase treated cotton fabric has an improved softness than the control samples. It was found that using the immobilized cellulase reduced the weight and tensile strength, because the hydrolytic attack is only limited to the surfaces of cotton fibers.

Novel phosphorous–nitrogen containing poly(aryl ether ketone)s: synthesis, characterization, and thermal properties

Xuexia Xie,Zhou Wang,Kun Zhang,Jing Xu

Synthesis, characterization and thermal degradation of phosphorus–nitrogen containing poly(aryl ether ketone)s

Xuexia Xie,Zhou Wang,Kun Zhang,Jing Xu

A series of high-molecular-weight poly(aryl ether ketone)s with phosphorus and nitrogen on their side and main chains was synthesized by a nucleophilic substitution polycondensation of 6-(4-hydroxyphenyl)pyridazin-3(2H)-one (HPZ) with 1,1′-bis(4-hydroxyphenyl)-metheylene-bispheny-1-oxophosphine oxide (DOPO-PhOH) and 4, 4′-difluorobenzophenone (DFBP) at various molar ratios. The structures of the poly(aryl ether ketone)s were characterized by means of Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H NMR, 31P NMR) and elemental analysis. The influence of the nitrogen- and phosphorus-containing monomer ratio on their thermal stability was investigated by adjusting the proportion of the HPZ and DOPO–PhOH from 0:10 to 8:2. The polymers were readily soluble in polar organic solvents, such as N-methylpyrrolidone (NMP), N, N-dimethylacetamide (DMAc), N, N-dimethylformamide (DMF) and chloroform. Differential scanning calorimetry (DSC) demonstrated that these polymers have an amorphous morphology.

Polychlorinated biphenyls and their different level metabolites as inhibitors of glutathione S-transferase isoenzymes

Xingguo Tian,Erqun Song,Ruxian Pi,Xiaokang Zhu,Lichao Liu,Xiaoyan Ma,Hui Dong,Jing Liu,Yang Song

Research on the effects of polychlorinated biphenyl (PCB) toxicity tends to focus on commercial PCB congeners and parent PCBs themselves. However, studies have suggested that PCB metabolites may be more interesting than the parent compounds because of their high reactivity. As a key metabolic enzyme, glutathione S -transferases (GSTs) are responsible for detoxification by catalyzing the conjugation reaction of glutathione (GSH) to xenobiotics. Inhibition of GST activity indicates reduced detoxification ability. We investigated the inhibition of chicken liver GSTs by parent PCBs and their metabolites and observed dose-dependent inhibition in vitro ; inhibitory efficiency declined in the order GSH-conjugate   >   mono-hydroxyl ≈ quinone ≈ hydroquinone   >   parent PCB. Structure–inhibitory activity relationship studies indicated that with the inhibitory activity greatly increases with the number of GSH moieties or chlorine substituents on the quinone ring. However, no significant linear relationship was observed for chlorine pattern changes on the phenyl ring. The reversibility of PCB metabolite inhibition of GSTs is discussed. PCB mono-hydroxyl, hydroquinone and quinone forms showed irreversible inhibition of GSTs, which suggests a mechanism involving covalent binding to cysteine residues in the GST active site. PCB glutathionyl conjugates showed reversible GST inhibition, implying non-covalent binding. Furthermore, reactive oxygen species did not significantly affect GST activity.

Anatase TiO2/Defective UiO-66 porous octahedral S-scheme heterojunctions toward optimized photocatalytic performance

Mingtao Wang,Shijie Wang,Zhenzi Li,Xuepeng Wang,Liping Guo,Haixia Liu,Lijun Liao,Wei Zhou

Photocatalysis is an alternative for antibiotics removal from wastewater for the sustainable development of human society. However, applying photocatalysts for antibiotics (e.g., tetracycline) degradation under practical conditions is highly restricted by the low reaction efficiency due to the prompt charge recombination. Constructing porous heterojunctions is an efficient way to regulate the electron transfer path and accelerate charge migration efficiency. Herein, TiO 2 /defective UiO-66 porous octahedral S-scheme heterojunctions are successfully fabricated through an in-situ growth strategy. The strong interaction and charge migration behavior between TiO 2 and defective UiO-66 have been studied using X-ray photoelectron spectroscopy and electron paramagnetic resonance measurements. The photocatalytic removal efficiency of tetracycline is notably improved by forming TiO 2 /defective UiO-66 porous heterojunctions. The promoted photocatalytic performance can be ascribed to the strong interaction between TiO 2 and defective UiO-66, and the accelerated charge separation and transfer efficiency due to the formation of S-scheme heterojunctions, thus generating abundant reactive oxygen species, including O 2 − and OH. The optimized 38-TiO 2 /UiO-66-300 can eliminate 97.9 % of tetracycline in 60 min with a reaction constant rate of 0.0425 min −1 , which is approximately 4 and 10 times that of pristine TiO 2 and UiO-66-300, respectively. This work provides an alternate strategy for preparing highly active heterojunction photocatalysts for environmental applications.

Photocatalytic and fouling resistant MXene/3D-S-COF for efficient oil-water emulsion separation

Yanqing Qu,Yang Liu,Xiaoyu Du,Hongge Jia,Shuangping Xu,Mingyu Zhang,Bingyang Liu

Three-dimensional sphere covalent organic framework (3D-S-COF) membranes have received increasing attention in the field of oily wastewater and industrial organic matter due to their rich pore structure as well as having many exposed functional group sites. However, the synthesis of conventional imine COF through the Schiff base method, which suffers from the easy hydrolysis under organic solvent conditions. Herein, a novel super-wettable MXene/3D-S-COF composite membrane for oil–water emulsion separation was prepared by depositing MXene nanosheets on oxidized amide COF from the imine COF. The hydroxyl groups of the COF membrane not only improved the water permeability but also formed hydrogen bonds with the MXene layer, which enhanced the interaction and formed the high stability composite membrane. The porous 3D-S-COF and the zigzag MXene layer work synergistically to enable emulsion fluxes up to 240 L·m −2 h −1 bar −1 and the separation efficiency is more than 98 %. In addition, the residual mass of the composite membrane remained above 95 % after 10 days of immersion in various solvents, and it also has photocatalytic properties and good resistance to fouling. This study provides a brand new idea for the use of MXene/3D-S-COF based composite membrane for oil–water emulsion separation.