Experimental investigation on the yield loci of PA66

Compression, tensile and mixed compression/shear tests were performed on PA66 by using a universal material testing machine in order to identify the experimental yield loci of PA66. For the mixed compression/shear tests, instead of using a complex loading device, SCS (shear-compression specimens) were used to generate the additional shear stresses. Then, the mechanical behavior of materials under complex stress states can be obtained for further analysis. Results show that the experimental yield loci of PA66 obtained by the test method proposed in the present paper agree well with the theoretical model based on three stresses invariant, which indicates the reliability of the test method.     

Self-assembly and characterization of Ca-Al-LDH nanohybrids containing casein proteins as guest anions

Casein, a natural biopolymer contained in milk, has been successfully intercalated into a Ca-Al-LDH host structure. Synthesis was performed by rehydration of tricalcium aluminate in the presence of casein. The resulting nanohybrids were characterized by powder X-ray diffraction (XRD), elemental analysis, infrared spectroscopy (IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Further experiments revealed that the single protein strains intercalate instead of the entire casein sub micelles, which are present in milk. Additionally, the pure phospho protein fractions α- and β-casein, which make up ∼80 wt% of total casein were isolated and intercalated into the Ca-Al-LDH host structure, yielding a biopolymer-inorganic hybrid material.     

Bi2Fe4O9/g-C3N4/UiO-66三元复合材料的协同光催化作用

通过水热法合成具有协同机制的三元复合材料Bi₂Fe₄O₉/g-C₃N₄/UiO-66,研究表明三元复合光催化剂的催化活性要高于二元材料和纯材料。这主要是由于Bi₂Fe₄O₉更易于和g-C₃N₄结合形成稳定的Z-scheme异质结结构,使三元复合材料增强了可见光响应能力,提高了电子-空穴分离能力,增强了空穴和电子的氧化还原能力。     

Polypyrrole Grafts Synthesized via Electrochemical Polymerization

Abstract

Electrically conducting polypyrrole grafts with poly[(methyl meth-acrylate)-co-(2-(N-pyrrolyl) ethyl methacrylate)] (PMMA-co-PEMA) were synthesized by constant potential electrolysis. Cyclic Voltammetry, DSC, TGA, SEM and elemental analysis were used in order to characterize the free standing films. Conductivities of the polymers were measured by a four-probe technique.     

Molybdenum (VI)‐functionalized UiO‐66 provides an efficient heterogeneous nanocatalyst in oxidation reactions

A novel heterogeneous nanocatalyst was established by supporting molybdenum (VI) on Zr₆ nodes in the structure of the well‐known UiO‐66 metal–organic framework (MOF). The structure of the UiO‐66 before and after Mo (VI) immobilization was confirmed with XRD, DR‐FTIR and UV–vis spectroscopy, and the presence and amount of Mo (VI) was identified by X‐ray photoelectron spectroscopy and inductively coupled plasma atomic emission spectroscopy. TEM imaging confirmed the absence of Mo clusters on the MOF surface, while SEM confirmed that the appearance of the MOF has not changed upon immobilizing the Mo (VI) catalyst. BET adsorption measurements were used to confirm the porosity of the catalyst. The catalytic activity of this heterogeneous catalyst was investigated in oxidation of sulfides with H₂O₂ in acetonitrile and oxidative desulfurization of dibenzothiophene. Easy work up, convenient and steady reuse and high activity and selectivity are prominent properties of this new hybrid material.     

Bi2WO6/UiO-66复合材料的制备及其光催化性能

通过水热法制备了一种复合光催化剂Bi_2WO_6/UiO-66,探究了模板剂乙酸(CH_3COOH)对Ui O-66形貌的影响和2种中心元素Bi与Zr的不同物质的量之比对光催化性能的影响。通过XRD、SEM、N_2吸附-脱附、UV-Vis DRS、XPS等对催化剂的物相、形貌、比表面积、光吸收性能、元素组成等进行表征。实验结果表明,当n_(Bi)∶n_(Zr)=2∶1时,Bi_2WO_6/UiO-66对罗丹明B(RhB)的光催化活性最高,可见光照射50 min后,RhB的相对浓度降低98.5%。经过5次循环利用实验,催化剂的光催化活性没有明显下降,说明复合光催化剂的稳定性高。根据自由基捕获实验证明了空穴(h~+)为光催化中起决定性作用的活性物质,结合电化学测试以及UV-Vis DRS表征提出了可能的光催化降解机理。     

A review of recent advances in catalytic combustion of VOCs on perovskite-type catalysts

Along with the rapid development of industry, VOCs gradually move into the spotlight, and now become a kind of harmful environmental pollutants that cannot be overlooked. This paper introduces the hazards of VOCs and the common catalytic combustion catalysts, noble metal catalysts and non-noble metal catalysts, for the elimination of VOCs. Perovskite catalysts, as one of the non-noble catalysts, play an important role in the field of catalytic combustion in recent years. According to the classification of elements doping in perovskites, the research achievements in the past five years were analyzed and reviewed. In addition, this paper also analyzes and elaborates the reaction kinetics and QSAR/QSPR models for the introduction of structural properties and reaction mechanisms.     

UiO-66-NH2负载铜催化剂的制备及其对醇的催化氧化

通过溶剂热法成功制备了一种基于金属有机骨架(MOF)的复合材料Cu-Cu₂O/UiO-66-NH₂,采用傅里叶变换红外光谱(FTIR)、X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)对材料进行全面表征。在空气作氧化剂条件下,以苯甲醇氧化为苯甲醛作为模型反应,系统地考察了溶剂、温度、催化剂各组分用量等因素对催化效果的影响。研究结果表明,该复合催化剂在醇选择性氧化反应中表现出优异的催化性能,60℃下反应5 h便可将苯甲醇定量转化为苯甲醛,并对其他苄基醇、烯丙基醇和杂芳基醇等底物也展现出良好活性。此外,循环利用3次后,该催化剂活性几乎不变,表明其具有良好的稳定性和重复使用性。