受阻胺类光稳定剂改性文物保护材料B72

为了提高B72文物保护材料的耐光性能,采用HALS-622等6种受阻胺光稳定剂对丙烯酸类文物保护材料B72进行改性。结果表明,HALS-5060稳定剂在添加后及老化过程中颜色明显变黄,不宜用作B72改性材料。高相对分子质量(简称分子量,以下同)受阻胺HALS-622、HALS-944比低分子量受阻胺HALS-480、HALS-508和HALS-292稳定效果好,尤其是低碱性的HALS-622受阻胺。因此,采用高分子量、低碱性的受阻胺改性B72是延长其使用寿命、对文物进行有效保护的新途径。     

聚合物型受阻胺光稳定剂——Tinuvin 622

Tinuvin 622是瑞士Ciba-Geigy公司的高效、高分子量型受阻胺光稳定剂。作为一种无毒的工业化学品,早已获得FDA认可,允许在聚烯烃食品包装材料中使用。Tinuvin 622与聚烯烃树脂有良好的相容性,极低的挥发性和低迁移性,为白色粉末。分子式为     

受阻胺对聚丙烯的防老化作用

介绍了受阻胺对聚丙烯的光稳定、热稳定作用,以及受阻胺与其它稳定剂之间的相互作用,低／高分子量受阻胺的并用效能。     

不同受阻胺光稳定剂改性聚丙烯耐光老化性能研究

分析了4种受阻胺光稳定剂在聚丙烯(PP)加工过程中的热稳定性,并研究其单一和复合使用对PP其光稳定性能和力学性能的影响。以失重率为10%时的热分解温度衡量受阻胺光稳定剂的热稳定性,结果表明,受阻胺光稳定剂的加入,使PP的光稳定性能增强;高低分子量受阻胺复合使用,可降低PP的黄变因数和羰基指数,增加其拉伸强度及冲击强度保持率;GW622、GW944和Tinuvin144复合使用效果最佳。     

受阻胺光稳定剂622投产

年产300t聚合型高分子量受阻胺光稳定剂622已在北京优帝化工有限公司所属的北京花山助剂厂投产。该产品是北京化工研究院多年科研的成果。 该光稳定剂可用于PE,PP、PS以及ABS、SBS等高分子材料。也可用于PU、PA、POM、聚酯等。与抗氧剂、紫外线吸收剂并用.有协同效应,能进一步提高制品的耐热、耐光老化效果。此产品为美国FDA批准可用于食品包装。 (以上由本刊通讯员提供)受阻胺光稳定剂622投产~~     

HALS研发进展及其在PVC中的应用

介绍了近年来受阻胺类光稳定剂(HALS)新产品的研究开发情况,高分子量化受阻胺、多功能化受阻胺、低碱性化受阻胺和反应型受阻胺等不断出现;应用研究取得新进展,对PVC体系中有较好稳定的作用。     

高分子量受阻胺光稳定剂的合成及其在PBS中的应用

通过可逆加成-断裂链转移聚合合成了一系列高分子量且窄分布的受阻胺光稳定剂,研究了其在生物可降解材料聚丁二酸丁二醇酯(PBS)中的应用。通过熔融共混的方法将不同分子量的光稳定剂添加进PBS中,进行人工加速老化实验,并通过傅里叶全反射红外光谱、分子量、力学性能等表征材料的老化程度和老化机理,并以抽提实验探究光稳定剂在PBS中的迁移。结果表明,相比于低分子量的光稳定剂,高分子量的受阻胺光稳定剂能够对PBS材料起到很好的保护效果,明显延长了PBS的使用寿命。     

受阻胺光稳定剂Tinuvin——622结构测定

(一)前言受阻胺光稳定剂的大分子化是近年来受阻胺光稳定剂发展的最重要方向,Tinuv in-622(简称622)是汽—嘉公司最近合成的新型大分子受阻胺光稳定剂,据称,它具有较好的防光性能,特别是由于大分子化,使它的耐抽提性,耐热性均优于770,并声称,由于622的出现,已使丙纶防老问题基本上得到解决。但对622的结构一直严加保密,1981年来     

受阻胺光稳定剂的多功能性及其结构优化

简述了在高分子材料中受阻胺光稳定剂（HALS）作用的机理以及其他功能,并介绍了目前从结构上对受阻胺光稳定剂进行的性能优化的4种主要途径：高相对分子质量化,引入其他功能基团,低碱性化和提高相容性。     

受阻胺/热塑性聚氨酯复合材料的结构与性能研究

对受阻胺/热塑性聚氨酯复合材料的结构和性能进行研究.结果表明,受阻胺GW-622均匀分散在受阻胺GW-622/TPU复合材料中,受阻胺GW-944在受阻胺GW-944/TPU复合材料存在少量团聚体;随着受阻胺用量的增大,受阻胺/TPU复合材料高温区的阻尼性能显著提高;与TPU相比,复合材料的拉伸强度大幅下降.     

Synthesis,characterization, and electroluminescent properties of a novel perylene‐containing copolyimide

A novel diphenylfluorene‐based Cardo copolyimide containing perylene (PFB5) was designed and synthesized by polycondensation of a diamine 4,4′‐(9H‐fluoren‐9‐ylidene)bisphenylamine with perylene dianhydride and another dianhydride in m‐cresol with isoquinoline as a catalyst at 200°C. PFB5 was characterized by FTIR, EA, GPC, TGA, DSC, UV‐vis, and PL. Because of the existence of the bulky diphenylfluorene units in the backbone, PFB5 showed high thermal stability and good solubility in common solvents such as chloroform. Solubility of PFB5 in low boiling point solvents allows direct spin coating of the polymer films, which exhibit intense photo‐ and electroluminescence (EL) in the visible range. This nonconjugated polymer could be used as emitting and electron‐hole transporting layers in polymer electroluminescent devices (PELDs). EL properties of the unilayer ELDs based on PFB5 are discussed. The device emitted a greenish yellow light. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 786–791, 2003     

Light and Shape-Memory Polymers: Characterization,Preparation, Stimulation,and Application

Shape-memory polymers (SMPs) are smart materials that change shape when exposed to stimuli and have various applications in different fields due to their unique properties. Light, as a kind of electromagnetic radiation, plays an important role in understanding the structure-property relations of SMPs, preparing original shapes, using them as non-contact stimuli sources, and tuning the optical properties of SMPs. This review provides a comprehensive review of the involvement of light in structure-preparation-stimuli-application of SMPs. The review is divided into four sections. First, applications of optical/spectroscopic approaches that provide information for understanding structure-property relations in SMPs, especially during programming and recovery. Second, describes how to build SMPs with light, including different photochemical reactions and 3D photocuring technologies. Third, discusses how light is used to trigger the shape change of SMPs through both photochemical and photothermal mechanisms. Last, focuses on how to take advantage of the shape-memory effect to tune the optical characteristics of polymers, including various structures of SMP color-changing materials and their synthetic strategies. Future research could focus on developing efficient photothermal fillers, new 3D printing techniques for SMPs, exploring their use in biomedical and wearable devices, and optimizing SMPs for industrial applications.     

Color rendering,a reassessment

The deficiencies of the CIE method of measuring and specifying colour rendering properties of light sources are discussed. © 1999 John Wiley & Sons, Inc. Col Res Appl, 24, 197–206, 1999     

光对烟草生长发育、生理代谢活动及品质形成影响的研究进展

光是影响烟草生长发育和生理代谢的重要生态因子之一。综述了近年来有关光强和光质对烟草生长发育、生理代谢活动及品质形成影响的研究进展,并分析了今后该领域的主要研究重点。     

Nicotinonitrile centered luminescent polymeric materials: Structural,optical, electrochemical,and theoretical investigations

Herein, we describe the design, synthesis, and structural characterization of three new push-pull type conjugative polymers, that is, VPPy _1-3 comprising strong electron-withdrawing N-heterocyclic nicotinonitrile scaffold coupled with electron-donating phenylene units through vinylene bridges, as promising candidates for optoelectronic applications. They were successfully synthesized from their respective co-monomers by simple polycondensation synthetic routes, viz. Knoevenagel and Wittig reactions. All the polymers were subjected to photophysical, electrochemical, thermal, and theoretical studies in order to ascertain their suitability in polymer light-emitting diode applications as blue emitters. Evidently, they are readily soluble in most of the organic solvents, enabling them easy solution-processable. These new polymers display strong blue photoluminescence at the peak in the range of 431 to 462 nm with a wide optical bandgap in the order of 2.55 to 2.63 eV. The obtained electrochemical data were employed to evaluate their HOMO/LUMOs. The density functional theory calculations generated useful information on their FMO, molecular geometries, and electronic properties. Also, the influence of their structural modification on the above-said properties was discussed in detail to reveal the structure-property relationship. Conclusively, these results illustrate the great prospective of this class of polymeric materials for the application in solution-processable blue LEDs.     

Highly thermally stable single-component warm-white-emitting ZANP glass: Synthesis,luminescence, energy transfer,and color tunability

Luminescent glass demonstrates potential for applications as color converters in white-light-emitting diodes (W-LEDs). In this study, solution combustion synthesis combined with low-temperature melt quenching was employed as a novel route for preparing new white-light fluorescent glasses (rare-earth-doped ZnO–Al₂O₃–Na₂O–P₂O₅, ZANP). The developed solution combustion synthesis can considerably decrease the reaction temperature and time, with several advantages such as energy and time savings. X-ray diffraction and photoluminescence spectroscopy, as well as decay curves, CRI, and CCT, as well as the Commission Internationale de I′Eclairage (CIE) 1931 chromaticity coordinates, were assessed to examine the microstructure and photoluminescence properties of Tm³⁺/Dy³⁺ co-doped and Tm³⁺/Dy³⁺/Eu³⁺ tri-doped ZANP glasses for use in W-LEDs. Experimental results revealed that ZANP glass co-doped with Tm³⁺ and Dy³⁺ exhibits blue- and yellow-light emissions based on the energy transfer of dipole-dipole interaction between Tm³⁺ and Dy³⁺, which can realize the adjustment of color in a wide range. The emitting color coordinate (0.343, 0.344) of ZANP: 1.0Tm³⁺, 0.75Dy³⁺ approach ideal white light. Also, by the introduction of additional Eu³⁺ doping, ZANP:1.0Tm³⁺, 0.75Dy³⁺, 0.1%Eu³⁺ glass emit warm-white light (CCT = 3198?K) under an excitation of 361?nm. Moreover, the tri-doped ZANP glasses exhibit good thermal stability, where the luminous intensity at 498?K remains exceeding 50% of that at room temperature, and the color coordinate offset is only 2.87?×?10^?2 relative to room temperature.     

Perfluorosulfonic ionomer solution in N,N‐dimethylformamide

The morphology of perfluorosulfonic ionomer molecules in N,N‐dimethylformamide was investigated at different concentrations. Rheological, dynamic light scattering (DLS), and scanning electron microscopy (SEM) measurements were performed on the prepared perfluorosulfonic ionomer solutions or films. The ionomer molecules shrank from rodlike granules to spherelike ones at relatively low concentrations, and the spherelike granules aggregated together to form aggregates at higher concentrations, with capillary liquid bridge force as the driving force. As the solvent evaporated slowly at room temperature, the SEM image showed that the film was loosely stacked by granules and that aggregates formed in the solution. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Nocturnal Light Pollution Induces Weight Gain in Mice and Reshapes the Structure,Functions, and Interactions of Their Colonic Microbiota

In mammals, the daily variation in the ecology of the intestinal microbiota is tightly coupled to the circadian rhythm of the host. On the other hand, a close correlation between increased body weight and light pollution at night has been reported in humans and animal models. However, the mechanisms underlying such weight gain in response to light contamination at night remain elusive. In the present study, we tested the hypothesis that dim light pollution at night alters the colonic microbiota of mice, which could correlate with weight gain in the animals. By developing an experimental protocol using a mouse model that mimics light contamination at night in urban residences (dLAN, dim light at night), we found that mice exposed to dLAN showed a significant weight gain compared with mice exposed to control standard light/dark (LD) photoperiod. To identify possible changes in the microbiota, we sampled two stages from the resting period of the circadian cycle of mice (ZT0 and ZT10) and evaluated them by high-throughput sequencing technology. Our results indicated that microbial diversity significantly differed between ZT0 and ZT10 in both LD and dLAN samples and that dLAN treatment impacted the taxonomic composition, functions, and interactions of mouse colonic microbiota. Together, these results show that bacterial taxa and microbial metabolic pathways might be involved with the mechanisms underlying weight gain in mice subjected to light contamination at night.     

Asphaltene/polymer composites: Morphology,compatibility, and rheological properties

In this study, we investigate the use of asphaltene, a natural waste product that is inevitably formed during heavy oil processing, as a filler in polymer composites. The focus of this work is on the compatibility of various asphaltenes, featuring different polarities, with several polymers, including polypropylene (PP), polystyrene (PS), polymethyl methacrylate (PMMA), and polycarbonate (PC). The Hansen solubility parameters were plotted to predict the compatibility of polymers with different asphaltenes. Then, polymer composites were prepared by two common techniques: melt mixing and solution mixing. The dispersion state of the asphaltenes in each polymer was investigated by using imaging and rheological techniques. This work showed that the network structure of the asphaltenes and, thus, the final properties of the composites can be controlled by the polarity of asphaltenes, mixing technique, and melt viscosity of the polymer. For instance, more polar asphaltene (Asph P) produced smaller aggregates in PMMA, which has a higher polar solubility parameter than PP or PS. At 2.5 wt.% of asphaltene, Asph P showed 26% and 177% larger asphaltene agglomerates in PP and PS, respectively, than the less polar asphaltene (Asph Al). PS/asphaltene and PMMA/asphaltene composites prepared by the solution mixing method exhibited better dispersion compared to their melt-mixed counterparts. In melt-mixed composites, the dispersion quality of the asphaltene was better for polymers with higher melt viscosity. Thus, a careful choice of polymer, asphaltene, and preparation conditions can be used to tune the properties of asphaltene/polymer composites.     

Synthesis,performance and action mechanism of carbon black/Ag3PO4 photocatalysts

Novel carbon black (CB)/Ag₃PO₄ compound photocatalysts were synthesized from a hydrothermal method and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and electrochemical methods. The photocatalytic oxidation ability of CB/Ag₃PO₄ was evaluated through methyl orange degradation experiments under visible light irradiation. The CB/Ag₃PO₄ showed higher photocatalytic activity than pure Ag₃PO₄. It was indicated the compound catalysts could absorb and utilize more optical energy to improve the photocatalytic activity, which was attributed to the ability of carbon black to accelerate the electron-hole separation. In particular, the methyl orange photocatalytic degradation rate over the 7?mg/L CB/Ag₃PO₄ was 1.6 times that of Ag₃PO₄. And the results of the cyclic experiment show that the photocatalyst has good stability. Moreover, the mechanism about the photocatalytic activity of CB/Ag₃PO₄ compounds was investigated. In this photocatalytic reaction, ?OH was the major active substrate responsible for the visible-light-driven degradation.