负载型抗氧剂的制备及应用研究进展

如何有效克服小分子抗氧剂热稳定性低,易迁移及耐抽提性能差等缺点,是抑制高分子材料及其制品老化现象所亟待解决的关键问题之一。其中,采用化学法将小分子抗氧剂接枝到无机材料表面或聚合物分子链上制备负载型抗氧剂是一条重要的解决途径,已成为抗氧剂领域的研究热点。文中详细介绍了近年来通过无机材料和聚合物(低聚物)为载体制备负载型抗氧剂的方法及应用研究进展,总结了负载型抗氧剂的特性,提出了目前负载型抗氧剂研究面临的问题。     

国内外塑料用抗氧剂的发展现状与未来

本文主要介绍了近年来国内外塑料抗氧剂的现状和发展趋势。     

聚丙烯加工中复合抗氧剂QS215抗热氧老化效果的研究

本文介绍利用聚丙烯加工前后馆作流动速率变化评价抗氧剂效果的实验方法，以及聚丙烯加工中QS215复合抗氧剂与其它种类抗剂在抗热氧老化效果的比较。     

γ辐照下HALS与抗氧剂在PP中的并用效应及机理研究 I．γ辐照下HALS与抗氧剂在PP中的并用效应

研究了受阻胺光稳定剂PDS（4－（甲基丙烯酸）－2，2，6，6－四甲基哌啶醇酯和苯乙烯的共聚物）与几种类型抗氧剂在γ－辐射下在聚丙烯中的并用效应。实验发现，PDS与受阻酚抗氧剂Irganox1076、Irganox1010并用时表现出明显的协同效应，而PDS和Irganox1098并用时并未发生明显的协同效应。PDS与含磷抗氧剂Irgafos168、含硫抗氧剂Irganox PS802以及芳香胺类抗氧剂4010并用均表现出一定的协同效应。PDS与4010并用的效果比与其它类型抗氧剂的并用效果都好，PDS和混合抗氧剂的并用效果不如和单一抗氧剂的并用效果，PDS和混合抗氧剂的并用时还可能出现反协同效应。     

塑料抗老化助剂的应用

正抗氧剂是聚合物稳定剂的重要分支,被广泛地应用于橡胶、塑料、化纤高分子材料及石油化工和食品加工中。目前已有200多个品种,按照用途分为塑料、纤维抗氧剂、橡胶防老剂、石油抗氧剂、食品抗氧剂和防煤炭自燃抗氧剂;按照化学结构分为仲芳胺类、受阻酚类、亚磷酸酯类、酰肼类、碳自由基捕获剂类、维生素E类及复合类等。1受阻酚类抗氧剂受阻酚抗氧剂是塑料材料的主抗氧剂,按分子结构分为单酚、双酚、多酚、氮杂环多酚等品种。单酚和双酚抗氧剂,如     

γ辐照下HALS与抗氧剂在PP中的并用效应及机理研究 Ⅰ.γ辐照下HALS与抗氧剂在PP中的并用效应

研究了受阻胺光稳定剂PDS(4-(甲基丙烯酸)-2,2,6,6-四甲基哌啶醇酯和苯乙烯的共聚物)与几种类型抗氧剂在γ-辐射下在聚丙烯中的并用效应.实验发现,PDS与受阻酚抗氧剂Irganox 1076、Irganox 1010并用时表现出明显的协同效应,而PDS和Irganox 1098并用时并未发生明显的协同效应.PDS与含磷抗氧剂Irgafos 168、含硫抗氧剂Irganox PS802以及芳香胺类抗氧剂4010并用均表现出一定的协同效应.PDS与4010并用的效果比与其它类型抗氧剂的并用效果都好,PDS和混合抗氧剂的并用效果不如和单一抗氧剂的并用效果,PDS和混合抗氧剂的并用时还可能出现反协同效应.     

浅谈车用润滑油使用寿命的抗氧剂含量检测技术研究现状及进展

抗氧剂是车用润滑油的重要组分之一,评估车用润滑油的使用寿命的主要指标之一可以通过测定其残留含量,这也是当前研究的热门内容之一。本文介绍了近年来国内外关于车用润滑油中抗氧剂含量的测定方法的研究进展情况,主要包括热氧化技术、化学氧化技术、电化学技术、仪器分析技术四大类,并对今后的检测方法的发展方向进行了展望,为从事车用润滑油使用寿命检测技术的研究者提供参考。     

助剂对增透小本体聚丙烯透明性的影响

在成核剂增透小本体聚丙烯(NTPP)体系下,研究了润滑剂硬酯酸钙、抗氧剂B215和抗氧剂168用量对NTPP透明性能的影响,结果显示,少量的硬脂酸钙有利于NTPP透明性的提高,抗氧剂168对NTPP的透明性具有较大的影响,而抗氧剂B215对NTPP透明性影响较小.     

新型抗氧剂研究进展

近几十年来,高分子材料因具有高性能、易改性、质量轻等特点,已成为人们生产和生活中必不可少的一类材料.但高分子材料在加工、储存和使用过程中会发生氧化老化,延缓高分子材料氧化的方法较多,添加抗氧剂是其中简单且有效的方法.因此,对近10 a高分子材料抗氧剂的研究进行梳理,将其分为抗析出型、高效型和无毒环保型3类进行详细分析.根据高分子材料抗氧剂最新的发展动态,认为抗析出、高效和无毒环保是其研发的主要方向.大分子型抗氧剂、负载型抗氧剂和反应型抗氧剂能有效提升小分子抗氧剂的抗析出性能,其中,大分子型抗氧剂具有更好的发展潜力;分子内协同作用是抗氧剂高效化的有效手段;生物基抗氧剂是无毒环保型抗氧剂的主要研发方向.     

塑料输液包装材料中抗氧剂使用现状分析及建议

本文总结了塑料输液包装材料中常用的几种抗氧剂及其检测标准,同时对输液包装中的抗氧剂在药液中的迁移情况提出建议。     

Chitosan nanocomposite films incorporating cellulose nanocrystals and grape pomace extracts

Chitosan nanocomposite films incorporating grape pomace extract (GPE), either Cabernet Franc (CF; a red variety) or Viognier (a white variety), and cellulose nanocrystal (CNC) were prepared using a solvent casting method. Mechanical properties, water vapour permeability, color and opacity, crystalline structure, thermal properties, total phenolic content, and antioxidant activity of the films were characterized. Incorporating CNC alone significantly (P < .05) increased tensile strength of the films and decreased their percent elongation at break and water vapour permeability. Grape pomace extract had an opposite effect on mechanical properties by decreasing tensile strength but increasing percent elongation at break. Film color was mainly influenced by the presence and type of GPE. Films containing CF extract exhibited the darkest appearance with increased reddish and bluish hues. Addition of CNC significantly increased film opacity and the alignment of chitosan chains, while the effect of GPE was not significant. Thermal analysis showed that chitosan and CNC were partially miscible and that the addition of CNC did not significantly change decomposition temperature of the films. Incorporation of GPE significantly (P < .05) increase total phenolic content and antioxidant activity. Films containing CF had higher DPPH? radical scavenging capacity than their counterparts with Viognier. Film incorporating both CNC and CF shows greater potential for food packaging application because of a combination of improved physical properties and high antioxidant activity.     

Reaction of Sulfur,Hydrogen Sulfide,and Accelerators With Propylene and Butadiene

As part of a study of vulcanization, propylene as a model compound for natural rubber has been reacted with sulfur alone, with hydrogen sulfide alone, and with each of these materials in the presence of certain accelerators. Butadiene as a model compound for intermediate conjugated systems found in vulcanized rubber by means of infrared studies has been similarly studied. Results of mass spectrometer analyses of the volatile portions of the reaction products indicate the formation of sulfides, disulfides, and carbon-to-carbon bonds. Zinc dimethyl dithiocarbamate (ZnDMDC), a vulcanization accelerator, facilitates the formation of hydrogen sulfide from the olefin or diolefin in the presence of sulfur, and in turn promotes the reaction of hydrogen sulfide with the olefin and diolefin. The ZnDMDC-accelerated reaction of hydrogen sulfide and sulfur with the diolefin may account for the reduced conjugation observed in vulcanizates accelerated with ZnDMDC. Studies with free radical accelerators show that a mechanism other than a free radical chain mechanism is involved in the formation of diisopropyl sulfide in the reaction of propylene with sulfur (or hydrogen sulfide) and certain substances that facilitate the reactions. The same conclusion applies to the formation of a nonvolatile residue in the ZnDMDC-accelerated reaction between propylene and sulfur. Other phases of the reactions involve the formation of compounds from what appear to be free radical fragments of the original molecule. In most of the reactions, appreciable portions of the reaction products are nonvolatile.     

QCAR models to predict wild mushrooms radical scavenging activity, reducing power and lipid peroxidation inhibition

Wild mushrooms have become attractive as a source of physiologically beneficial compounds including antioxidants such as phenolic compounds and tocopherols. The concentrations of antioxidant compounds (phenolics and α-tocopherol) and EC₅₀ values of antioxidant activity (concentration required to achieve 50% of radical scavenging activity and lipid peroxidation inhibition, or 0.5 of absorbance in reducing power) were analyzed by partial least square (PLS) regression analysis. Three QCAR (Quantitative Composition-Activity Relationship) models were constructed and their robustness and predictability were verified by internal and external cross-validation methods. Antioxidant activity correlated well with phenolics and α-tocopherol contents, the major antioxidants in wild mushrooms. The models proved to be useful tools in the prediction of mushrooms radical scavenging activity, reducing power and lipid peroxidation inhibition.     

新型酚醛SMC增稠剂及增稠机理的研究

本文通过粘度实验,研究了酚醛片状模塑料(P-SMC)的新型增稠剂.结果发现,B₂O₃和ZnO混合体系是较好的酚醛树脂增稠剂;当在100份树脂中加入4份B₂O₃和1份ZnO时,可达到理想的增稠效果.文中还通过红外光谱探讨了B₂O₃和ZnO对酚醛片状模塑料的增稠机理,分析表明B₂O₃对树脂有较好的增稠作用,ZnO可延缓B₂O₃对树脂的增稠,使增稠时间调节到较为理想的程度.     

Characterization of antioxidant activity of extracts from Flos Lonicerae

Antioxidants are emerging as prophylactic and therapeutic agents for various diseases. However, little is known about the antioxidant property of the extract from Flos Lonicerae, a medically useful traditional Chinese medicine herb. Here the antioxidant capacity of water, methanolic and 70% ethanolic extracts prepared from Flos Lonicerae to scavenge DPPH radical and reduce Fe³⁺ to Fe²⁺ is evaluated. Chlorogenic acid, a major component of Flos Lonicerae, is identified and further purified from 70% ethanolic extract with HPLC and its antioxidant capacity is also characterized. The content of total phenolic compounds and chlorogenic acid in Flos Lonicerae is determined. The present results demonstrate that all Flos Lonicerae extracts examined here exhibit antioxidant activity and chlorogenic acid is a major contributor to this activity, which implicates that the Flos Lonicerae extract may serve as potential source of natural antioxidants for treatment of some diseases.     

The process window for diamond deposition from the vapor phase with sulfur in the C–H–O feed gas mixtures

Theoretical predictions using a modified radical species ternary diagram for C–H–O system indicate that addition of sulfur expands the C–H–O gas phase compositional window for diamond deposition. Sulfur addition to no-growth domain increases the carbon super-saturation by binding the oxygen and the addition of sulfur to the non-diamond domain reduces the heavy carbon super-saturation by decreasing C_nH_m species concentration in the gas phase. The overall effect of sulfur addition to gas phase mixtures is characterized as that of oxygen addition to the C–H system, i.e. expansion of the compositional window over which diamond can be deposited from the gas phase. In addition, the increasing sulfur concentration to diamond domain feed gases beyond 2000 ppm did not affect the steady state gas phase composition but the quality of diamond was reduced.     

Silver-nanoparticle immobilized initiator and co-initiators for free radical polymerization

The specific properties of silver-nanoparticle immobilized initiator and co-initiators for free radical polymerization were studied. The silver-nanoparticle immobilized benzophenone photoinitiates the free radical polymerization in both UV and visible regions. The photoinitiation ability of Bp-MPCs in visible region suggests a possible two-photon action even at low intensity of an incident light. The co-initiation process by MA-MPCs is more efficient in comparison to the co-initiation observed for corresponding free mercaptoamino acid. This behavior can be attributed to: (i) specific interaction of sulfur electron with surface plasmon electrons that make an electron transfer from mercaptoamino acid to excited electron acceptor more efficient, or (ii) to a locally higher concentration of electron donor (in the ligand shell) in comparison to classical a single-phase solution.     

淀粉与丙烯腈接枝共聚引发方法研究进展

淀粉与丙烯腈进行的接枝共聚反应是一种自由基反应，可以利用各种引发方法引发淀粉形成自由基，而后和丙烯腈进行反应。本文从引发机理、引发效果、以及引发过程中需要注意的问题等各个方面出发，对淀粉与丙烯腈接枝共聚的引发方法做一详细的介绍。     

Green synthesis of silver nanoparticles from grape and tomato juices and evaluation of biological activities

The biosynthesis of silver nanoparticles (AgNPs) is substantial for its application in lots of fields. Tomato and grape fruit juices were used as a reducing and capping agents for the biosynthesis of AgNPs. Ultraviolet spectroscopic analysis offered peaks in the range of 396‒420 nm that indicate the production of AgNPs. Fourier transform infrared spectroscopy analysis revealed attachment of different functional groups with Ag ion in both tomato and grape fruit extracts NPs. The X‒ray diffraction analysis confirmed that the synthesised AgNPs have a face centred cubic confirmation. Scanning electron microscopy confirms the size of NPs that varies from 10 to 30 nm. The DPPH free radical scavenging assay, total antioxidant capacity, reducing power assay, total flavonoid contents and total phenolic contents determination confirmed that synthesised AgNPs are potent antioxidant agents; can be used as an effective scavenger of free radicals. Biosynthesised AgNPs also showed good antibacterial activity against Pseudomonas septica, Staphylococcus aureus, Micrococcus luteus, Enterobacter aerogenes, Bacillus subtilis and Salmonella typhi. Protein kinase inhibition activity showed a clear zone which indicates anticancerous potential of biosynthesised AgNPs. The efficacious bioactivities indicate that the tomato and grape derived AgNPs can be used efficiently in pharmaceutical and medical industries.Inspec keywords: silver, nanoparticles, nanomedicine, biomedical materials, nanofabrication, Fourier transform infrared spectra, X‐ray diffraction, scanning electron microscopy, microorganisms, antibacterial activity, enzymes, cancer, ultraviolet spectraOther keywords: silver nanoparticle green synthesis, grape juice, tomato juice, biological activity evaluation, ultraviolet spectroscopic analysis, silver nanoparticle production, Fourier transform infrared spectroscopy analysis, silver ion, X‐ray diffraction analysis, scanning electron microscopy, DPPH free radical scavenging assay, antioxidant capacity, flavonoid content, phenolic content determination, antioxidant agent, antibacterial activity, Pseudomonas septica, Staphylococcus aureus, Micrococcus luteus, Enterobacter aerogenes, Bacillus subtilis, Salmonella typhi, protein kinase, size 10 nm to 30 nm     

Fullerenes and Nanotubes from Coal

Graphite has normally been used to synthesise fullerenes and nanotubes. However, coal is a cheaper and more suitable industrial material. Because coal is a molecular solid, unlike graphite, the mechanism by which fullerene and nanotubes are formed is different. Moreover, other products such as polyaromatic hydrocarbons (PAHs) and microfibres are also formed. In this review, the mechanism of formation of fullerene and nanotubes from coal is discussed. It is shown that the pathway involved is other than through the C₁ intermediate route. The influence of other elements in coal such as hydrogen, oxygen, sulfur and iron is also discussed. It appears that, hydrogen, oxygen, iron and sulfur affect the yield and type of fullerenes and nanotubes formed.