CdS@3DOM TiO2–ZrO2 composites with high efficiency photocatalytic properties prepared by template method combined with in-situ self-assembly technology

The three-dimensional ordered macroporous composites CdS@3DOM TiO₂–ZrO₂ were prepared by the template method combined with in-situ self-assembly technique. The composition, structure, morphology and surface physicochemical properties of composites were characterized by XRD, XPS, UV–vis/DRS, SEM, TEM, HR-TEM, PL, N₂ adsorption−desorption and EIS tests. The results show that CdS@3DOM TiO₂–ZrO₂ composites have strong light absorption in the visible region. And the in-situ self-assembled CdS particles in the composite do not destroy the excellent open pore structure, and the introduction of CdS further improves the charge separation efficiency. The results of multi-mode photocatalytic degradation of CdS@3DOM TiO₂–ZrO₂ show that the photocatalytic properties of CdS@3DOM TiO₂–ZrO₂ composites are obviously enhanced. In addition, the hydrogen production of CdS@3DOM TiO₂–ZrO₂ can reach 1323 μmol/g (8 h) in the photolysis of water experiment, which is 94.5 times than that of the commercially available P25, showing excellent photocatalytic performance.     

Biocompatible Catechol-Functionalized Cellulose-Based Adhesives with Strong Water Resistance

Numerous traditional adhesives have good adhesion in dry environments. However, non-environmental-friendliness and poor water resistance largely limit their practical applications. To prepare biocompatible adhesives with strong water resistance and adhesion strength, in this paper, catechol-functionalized cellulose-based adhesive polymers are synthesized by grafting N-(3,4-dihydroxyphenethyl)methacrylamide and methyl methacrylate onto cellulose chain through atom transfer radical polymerization (ATRP). The successful synthesis of the catechol-functionalized cellulose-based adhesive polymers is confirmed by FTIR and ¹H NMR. The different characteristics of the adhesive polymers, such as thermal stability, swelling ratio, biocompatibility, and adhesion strength are investigated. Strong water resistance on various substrates is realized in underwater environment for the catechol-functionalized cellulose-based adhesive with addition of Fe³⁺. The adhesion strength and thermal stability are enhanced when the catechol content is increased. The adhesive with catechol content of 25.4% shows the adhesion strength of 0.45 MPa for iron substrate in underwater environment. In addition, the adhesive with addition of Fe³⁺ exhibits excellent adhesion in dry environment, with maximum adhesion strength of 3.50 MPa for iron substrate. The cell culture test shows that the adhesive polymers have excellent biocompatibility. The biocompatible adhesives with strong water resistance have potential application in electronic, wood, and building fields.     

Activated carbon synthesis from tangerine peel and its use in hydrogen storage

Activated carbon samples were synthesized by chemical and physical activations of tangerine peel. The activated carbons were characterized via using Fourier Transform Infrared-Attenuated Total Reflectance spectroscopy (FTIR-ATR), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET), Differential Thermal Analysis-Thermogravimetry (DTA/TG) techniques. It was found that the activated carbon samples were porous, and their surface areas were increased by treating with the various concentrations of ZnCl₂ and KOH. After the formation of activated carbons, they turned into a structure that was formed from carbon atoms, and their residual amounts decreased. In addition, the hydrogen storage capacities of the activated carbon samples were measured in different pressures at 77 and 298 K using the Hiden IMI PSI instrument. The results, confirmed that the hydrogen storage capacities of the activated carbons were higher at the cryogenic temperatures, and higher hydrogen storage capacity were observed by the increasing concentrations of activation agents in the synthesized activated carbons. The activated carbons synthesized by ZnCl₂ had higher hydrogen storage capacity than those by KOH.     

动态力学分析技术(DMA)在食品研究中的优势及应用进展

动态力学分析(DMA)是研究高分子材料在各种环境中对于外部施加应力反馈的一种重要技术.近年来,随着学科交叉研究热度的不断上升,DMA在表征食品高分子材料中的力学特征研究中表现出极大的应用价值.因此,本文系统综述了DMA技术的工作原理、对食品材料的测定优势及在食品研究领域的具体应用,该技术在食品材料储能模量和损耗模量测定...     

Ultrasound propagation in two-layer gas flow

The ultrasonic signal propagation in two-layer gas flow was studied. The intensity degradation of the signal was observed while the signal was propagating through the air-hydrogen-air two-layer gas flowing system. The concentration of flowing hydrogen (H₂) gas was measured using ultrasound from the exterior of the pipe, and it was calculated that the intensity degradation of signal did not simply depend on the H₂ concentration, however, the intensity varied every second. Schlieren photography was taken to visualize the motion of H₂ gas after injecting into the flowing air of 2 m/s. It was observed that high concentration H₂ gas was flowing in the middle of the airflow without quick diffusion into the air. A two-dimensional air-H₂-air gas flow model was considered where 100% H₂ was flowing in the middle of the airflow, and the gas layers were separated by two fluctuated interfaces. According to the calculation using this model, only limited conditions of the signals can reach to the receiver due to the refraction at the fluctuating air-H₂-air gas interfaces while propagating. It was found that the receiver could hardly detect the signals; hence, the intensity of the signal looked degraded.     

Low-cost natural binder for particleboards production: study of manufacture conditions and stability

Nowadays, the majority of adhesives used in particleboards (PB) manufacture are formaldehyde-based. In the present research work a low-cost bioadhesive, based on the combination of thick spent sulfite liquor (TSSL) with wheat flour, was tested for the production of three-layer particleboards, at different conditions (particleboards target density, pressing time, pressing temperature, wood type and binder age). It was possible to produce particleboards with densities ranging from 682 kg m⁻³ to 783 kg m⁻³, at pressing temperatures from 180 to 210 °C, and pressing times between 8 and 10 min. All the particleboards produced in these conditions were in accordance with the internal bond strength requirements of standard EN 312 for particleboards type P2 (0.35 N mm⁻²). The best result (0.69 ± 0.01) N mm⁻² was obtained for particleboards pressed for 10 minutes at 200 °C with the recycled wood mix. Regarding resin stability, the particleboards manufactured with the binder, stored for 30 days, presented good internal bond strength ((0.58 ± 0.02) N mm⁻²), above the requirements of standard EN 312 for particleboards type P2.     

Extraction of cellulose nanocrystals from plant sources for application as reinforcing agent in polymers

In the last few decades, the usages of plant sources-based stiff fillers as reinforcement material in polymer composites have attracted significant interests of researchers. The crystalline part of the semicrystalline cellulose chains as found in the plant cell walls represents the most highly potential reinforcing agents for polymer. This review systematically covers the extraction of nano-sized cellulose crystals from plant cell wall which involving the applications of several highly effective techniques. The topic about the derivation of products functionality at each stage as well as their influences on the final reinforcing capability is also covered. Apart from these, a detailed overview of current knowledge on the surface modification of nanocellulose has been provided also. Inasmuch, this paper is desired to encourage the emergence of preparation of cellulose derivative nanocrystals with controlled morphology, structure and properties, so that enable positive development of biocompatible, renewable and sustainable reinforcing materials for polymer composites field.     

无铅铜基钙钛矿Cs2CuBr4的湿度传感性能

铅卤钙钛矿因其优异的光电性能引起了人们的极大关注,但由于其内在的不稳定性以及铅的毒性问题,限制了其实际应用。本文制得一种性能较稳定的无铅铜基钙钛矿Cs₂CuBr₄,利用其对湿度较为敏感的特性,创制了基于Cs₂CuBr₄敏感膜的石英晶体微天平（quartz crystal microbalance, QCM）湿度传感器。结果表明,当钙钛矿溶液的浓度小于0.4μg/μL时,敏感膜在11%~84%相对湿度下具有良好的湿度传感性能。其中最优浓度为0.3μg/μL（QCM-3）、薄膜质量398.95ng时,传感器具有高灵敏度（37.65Hz/% RH）,优异的对数线性关系（R²=0.9948）和快速的响应/恢复时间（5s/1s）。由此可见,无铅铜基钙钛矿Cs₂CuBr₄在湿度传感领域具有良好的应用前景。     

Upgrading Paper-grade Softwood Kraft Pulp to Dissolving Pulp by Cold Caustic Extraction

Cold caustic extraction has potential applications in the production of dissolving-grade pulps due to its ability to selectively remove hemicellulose from lignocellulosic materials. In this study,we demonstrate the conversion of paper-grade kraft pulp into dissolving pulp by a single-stage cold caustic extraction. Under the extraction conditions of 12 wt% NaOH lye,11% pulp consistency,a temperature of 35℃,and 2 h,a paper-grade softwood kraft pulp was purified to high-grade dissolving pulp with 97. 1% α-cellulose content,1. 2% pentosane content,and narrowed molecular weight distribution. The resulting extraction filtrate was concentrated by nano-filtration to obtain the hemicellulose content of 59. 0 g / L,while the permeate was a clear Na OH solution with 10. 9 wt% concentration. A process configuration was also proposed,integrating this cold caustic extraction process with existing pulp and paper production and multi-purpose utilization of the extraction filtrate.     

Exploring integration prospects of opal-based photonic crystals

Different methods of functionalisation of thin opal films are discussed, including synthesis of opals on pre-patterned substrates, post-synthesis electron beam lithography, preparation of opals with heterogeneous photonic band gap structure and integrating opals with light sources. These approaches have been tested experimentally and key technological problems have been identified.