胶粘剂老化机理及研究进展(上)

总结了不同环境因素(如水、氧、热、光和应力等)下胶粘剂材料的老化机理,综述了自然环境及人工加速老化试验下胶粘剂的老化行为、国内外研究情况。最后展望了胶粘剂老化研究动向和发展趋势。     

PE基木塑复合材料的光稳定化及其耐候性能研究

以高密度聚乙烯为树脂基体,同时并采用两种自主开发的木塑专用耐候母粒对其进行光稳定化改性,制备了PE基木塑复合材料,并对其耐候性能进行了研究。结果表明,耐候母粒LS-1和LS-2均对PE基木塑复合材料有较好的抗老化作用。经1000h的氙灯加速老化后,光稳定化改性前后的木塑复合材料的拉伸性能变化不大;改性后的木塑复合材料的冲击强度保持率明显提高,色差明显减小,其中LS-2的效果更佳。     

Investigation into Texture,Preferential Orientation,and Optical Properties of Zinc Oxide Nanopolycrystalline Thin Films Deposited by the Sol–Gel Technique on Different Substrates

ZnO nanopolycrystalline thin films were deposited by the sol–gel technique on glass and silicon, and compared systematically via atomic force microscopy, scanning electron microscopy, x-ray diffraction, UV–Vis spectrophotometry, and fluorescence spectrophotometry. The thickness of the ZnO films was measured by ellipsometric microscopy. A higher preheating temperature was needed to obtain films with a strong preferential orientation. The optimal annealing temperatures for c-axis films on glass and silicon substrates were 525°C and 750°C, respectively. The relative intensity of the blue–green emission peak tends to increase with the annealing temperature. When the film is annealed in N₂, the transmittance of the film reduces while the intensity of the blue–green emission increases.     

A new dithienosilole-based oligothiophene with methyldicyanovinyl groups for high performance solution-processed organic solar cells

A new linear dithienosilole-based oligothiophene end-capped with methyl and electron-withdrawing dicyanovinyl groups, DTS(Oct)₂-(2T-DCV-Me)₂, was prepared in good yield. This oligomer exhibited broad absorption spectra in bulk down to the near-IR region with the optical edge at 900 nm, resulting in an initially high power conversion efficiency of 5.44% in solution-processed organic solar cells using PC₇₁BM as an acceptor.     

国内外降解塑料发展动向

塑料为人类带来了方便,但同时也带来了日益严竣的环境问题。因此,降解塑料已引起了人们的极大兴趣,希望借此找到一个解决废弃塑料的最好方法。本文综述了降解塑料的分类以及国内外研究发屐情况及趋势。     

Flower-like MOF-derived Co–N-doped carbon composite with remarkable activity and durability for electrochemical hydrogen evolution reaction

Electrochemical hydrogen evolution reaction (HER) is one of the most economical, sustainable, and attractive methods to produce hydrogen. Contemporarily, it is still a challenge to develop low-cost catalysts with high activity and durability for HER. Herein, we report a simple strategy to develop a Co–N-doped carbon electrocatalyst derived from a new cobalt metal-organic framework (MOF). The new flower-like 2D→3D MOF {[Co(BIPA)(5-OH-bdc)](DMF)}_n (1) was constructed based on bis(4-(1H-imidazol-1-yl)phenyl)amine (BIPA) and 5-hydroxyisophthalic acid (5-OH-H₂bdc). After that, the Co–N-doped carbon composite Co-MOF-800 was prepared via calcination of MOF 1. Interestingly, Co-MOF-800 exhibited excellent electrocatalytic activity and durability for HER. The onset potential (0.12 V) and E_j=10 value (0.193 V) of the Co-MOF-800 electrode were comparable to that of the most active non-precious metal HER electrocatalysts derived from other MOFs. The HER performance of Co-MOF-800 was stable without degradation even after long-term cycling.     

[Zn2(H2O)3(2,2′-bipy)2(btc)][Zn(H2O)(2,2′-bipy)(btc)] ·8H2O: a novel zinc–carboxylate complex consisting of independently cationic and anionic chains

A novel zinc complex, [Zn₂(H₂O)₃ (2,2^′-bipy)₂(btc)][Zn(H₂O)(2, 2^′-bipy)(btc)]·8H₂O (1), (H₃btc=1,3,5- benzenetricarboxylic acid, 2,2^′-bipy=2,2^′-bipyridine) has been prepared by hydrothermal reaction of H₃btc, Zn(CH₃CO₂)₂·2H₂O and 2,2^′-bipyridine at 180 °C and characterized by single-crystal X-ray diffraction analysis. Complex 1 consists of independently cationic and anionic chains. The hydrogen bonding interactions between chains extend 1 into a two-dimensional supramolecular architecture.     

Inorganic–organic hybrid material containing β-cage: {[H2(en)]Co2(ox)(V4O12)}n

By using an organic ligand, a new inorganic–organic hybrid compound of cobalt oxalate-vanadate, {[H₂(en)]Co₂(ox)(V₄O₁₂)}_n 1, where en = ethylenediamine, ox = oxalic acid, has been synthesized hydrothermally from V₂O₅,CoCl₂·6H₂O,H₂C₂O₄·2H₂O and en. Crystal data 1, orthorhombic, Cmcm space group, a=11.624(2), b=9.968(2), c=14.900(3) Å, R1=0.0298, wR2=0.1172. Compound 1 possesses a three-dimensional open-framework with β-cage and is an antiferromagnetic matter.     

Mechanochemical route for sulphide nanoparticles preparation

Well-crystallized ZnS, CdS and PbS nanoparticles were successfully synthesized by the mechanochemical route from the corresponding acetates and Na₂S. X-ray powder diffraction and scanning electron microscopy were used to characterize the as-obtained products. The SEM measurements show the aggregates of small nanocrystals in which particle sizes of 5–18 nm were estimated by Scherrer's formula. Simple flow chart of the preparation of sulphide nanoparticles was presented.     

Preparation and characterization of vitrified CeO2 coated cBN composites

The performances of vitrified cBN composites are deeply affected by the wettability of vitrified bonds on cBN particles. CeO₂ coated cBN particles were successfully prepared for the further improvement of the covering and wetting of cBN by vitrified bonds. The microstructure and properties of vitrified cBN composites were characterized by scanning electron microscope (SEM), hot stage microscope (HSM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and flexural strength. Results showed that the prepared CeO₂ coating on the surface of cBN was uniform and dense. Besides, the improved wettability of vitrified bonds on CeO₂ coated cBN particles accompanied with the formation of Ce–O–Al and N–Si confirmed by XPS were supposed to conduce to enhancing the holding power of the vitrified bonds to cBN particles, which resulted in increasing the flexural strength of vitrified cBN composites by 9.16%. Thus, coating cBN with CeO₂ was a potential and effective method to obtain vitrified cBN composites with higher flexural strength.