Thermal degradation behaviors of phosphorus–silicon synergistic flame‐retardant copolyester

A novel phosphorus‐containing poly (ethylene terephthalate) (PET) copolyester/nano‐SiO₂ composite (PET‐co‐DDP/SiO₂) was synthesized by in situ polycondensation of terephthalic acid (TPA), ethylene glycol (EG), [(6‐oxide‐6H‐dibenz[c,e] [1,2]oxaphosphorin‐6‐yl)‐methyl]‐butanedioic acid (DDP), and nano‐SiO₂. The morphology of PET nanocomposites was observed by using transmission electron microscope and scanning electron microscope. It was found that the SiO₂ nanoparticles were dispersed uniformly at nanoscale in the copolyesters with content 2 wt %. The thermal degradation behavior of PET nanocomposites was investigated by thermogravimetric analysis performed with air and nitrogen ambience. The activation energies of thermal degradation were determined using Kissinger and Flynn–Wall–Ozawa methods, respectively. The results obtained from Kissinger method showed that the activation energy was increased with the introduction of SiO₂. Moreover, the activation energy is decreased for PET‐co‐DDP system in nitrogen and air. The results also indicated that the SiO₂ and DDP had synergic effect on the early decomposition and the late charring in air. Furthermore, in the PET‐co‐DDP/SiO₂ system, the activation energy increased when the DDP component increased. However, the opposite results were obtained when the Flynn–Wall–Ozawa method was used. That was because the Doyle approximation stands correct as the conversion degree is from 5% to 20%. The effects of SiO₂ and DDP on the PET thermal degradation were lower in nitrogen than in air. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

贡嘎山冰川退缩区土壤-植物-微生物功能多样性对磷循环的协同作用

对于植物和土壤微生物来说,磷是重要的生命元素。土壤磷的生物有效性随成土过程发生改变,同时植物和土壤微生物通过调整自身养分利用策略,对土壤磷循环产生影响。基于冰川退缩迹地土壤和植被原生演替序列,探讨了土壤-植物-微生物功能多样性的磷循环协同作用过程,分析了贡嘎山海螺沟冰川退缩区4次冰碛物出露时间(1980、1970、1958、1930年)退缩迹地上发育的土壤物理化学性质、磷形态和酶活性的演化规律。结果表明:①随着植被演替和土壤发育,海螺沟冰川退缩区土壤磷含量及其生物有效性发生明显改变; ②成土作用初期,微生物促进了原生矿物磷的转化,并为早期植被发育提供养分; 随着原生矿物磷释放量的减少,植物养分利用策略经历了由磷回收循环→简单获取→回收循环3个不同阶段; 另外,随着植被演替,微生物更多地参与有机磷活化,提升了植物养分重吸收效率; ③海螺沟冰川退缩区冰碛物磷的快速流失加剧了植物与微生物对磷的竞争。     

高校知识工作者胜任力评价方法

基于高校知识工作胜任力要素族内协同互补、族间共生抑制的性质提出了一种基于协同效应和共生效应的高校知识工作者胜任力评价方法,并对这种方法的具体应用以及优点进行了说明.     

电沉积基合金及其复合镀层在10%H2SO4中的腐蚀磨损特性研究

采用电刷镀技术制取了合金镀层和复合镀层,利用扫描电镜、能谱仪、射线衍射仪分别对镀层原始状态及其腐蚀磨损过程中的组织形貌、成分、和相组成进行了观察、分析.研究了在不同的载荷和速度条件下两种镀层的腐蚀磨损特性及腐蚀磨损的协同作用.结果表明本实验条件下,在较低的载荷和速度下,复合镀层的耐腐蚀磨损性能优于合金镀层,随着载荷和摩擦速度的增大,复合镀层的耐腐蚀磨损性能下降较合金镀层快.     

Study of intumescent flame-resistant fluoroelastomer

The efficiency of different intumescent flame-retardant (IFR) formulations designed to improve the flame resistance of fluoroelastomer (FKM) composites was studied. The proportion of ammonium polyphosphate (APP) with charring-foaming agent (CFA) in IFR systems, and the addition of synergists zinc borate (ZB) and ketonealdehyde resin (KR120) were investigated to show their effect on flame resistance of FKM. According to flame resistance tests, when the mass ratio of APP to CFA was 4∶1 as well as the loadings of IFR, ZB, KR120 were 83 parts per hundred resin (phr), 13phr, 25phr, respectively, the FKM-KR120/IFR-ZB composites had good synergetic flame resistant effect. TGA data showed that IFR and synergists could obviously lower the maximum weight loss rate of FKM composites and effectively increase the char residue at high temperature. The morphological structures of the composites observed by scanning electron microscopy (SEM) demonstrated that the addition of ZB and KR120 could clearly reduce the cracks in char residue and make the char layer structure more integrated and compact.     

Synergistic Enhancement of the Extraction of Trivalent Lanthanides and Actinides by Tetra‐(n‐Octyl)Diglycolamide from Chloride Media

Abstract

This work describes a unique synergistic enhancement of the extraction of trivalent actinides and lanthanides by extraction chromatographic resins containing tetra‐n‐octyldiglycolamide (TODGA) from hydrochloric acid containing anionic metal chlorides. The presence of mg/L quantities of trivalent Fe, Ga, In, Tl, or Bi in HCl leads to several orders of magnitude enhancement of the extraction of trivalent actinides and lanthanides. The synergistic effect persists, even when the amount of metal chloride exceeds the capacity of the resin. The application of this synergistic enhancement for the separation of actinium from stainless steel and the preconcentration of americium and plutonium from large soil samples will be described.     

无机阻燃剂在增塑聚氯乙烯中的应用

详细介绍了无机阻燃剂的阻燃机理，研究了各种无机阻燃剂对增塑聚氯乙烯性能的影响，同时发现了它们在阻燃方面的协同效应作用。     

蛇床子和苦参活性成分的联合毒力测定及混剂的抑菌活性

采用室内平皿菌丝生长速率法研究了蛇床子和苦参有效活性成分对烟草赤星病菌的毒力及联合毒力。结果表明蛇床子和苦参有效活性成分对烟草赤星病菌都有一定的抑制作用,EC50分别为80.0、27.9μg／ml,将两者按照一定比例复配后,EC50为33．3μg／ml,增效比值为2．80,具有明显的增效作用。同时研究了蛇苦混剂对病原菌的抗生作用、菌丝形态以及孢子萌发的影响。     

水处理中的无机混凝剂与有机絮凝剂的协同作用

实验研究了无机混凝剂与聚丙烯酰胺(PAM)系列有机絮凝剂在处理废水中的协同作用,探讨了絮凝剂的加药顺序、相对分子质量、所带电荷对絮凝效果的影响。结果表明在处理钻井废水时,FeCl3+PAM复合使用处理效果优于单纯使用FeCl3的处理效果;为达到较好的处理效果,应先加无机混凝剂;PAM相对分子质量应大于500万;在最佳加量时,处理效果顺序为PHP>APAM>CPAM>PAM。     

Interaction between the strong anionic character of strong anions and the hydrophobic association property of hydrophobic blocks in macromolecular chains of a water‐soluble copolymer

The copolymerization of acrylamide, sodium 2‐acrylamido‐2‐methyl propane sulfonate, and styrene was carried out in a microemulsion medium, and ternary copolymers based on polyacrylamide, which contained both strong anionic groups (? SO₃Na) and hydrophobic blocks (polystyrene), were synthesized. The structures and compositions of the copolymer were characterized by various means (Fourier transform infrared, ultraviolet, and elemental analysis). The aqueous solution properties were investigated with a florescence probe technique and apparent viscosity measurements, and the interactions between the strong anionic character of the anionic groups and the hydrophobic association behavior of the hydrophobic blocks was intensively examined. After the simultaneous addition of the strong anionic groups and hydrophobic association blocks to the main chains of polyacrylamide, the synergism of the electroviscosity effect of the strong anionic groups and the hydrophobic association effect of the hydrophobic blocks obviously enhanced the apparent viscosity of aqueous copolymer solutions, and the synergism of greater salt tolerance of the strong anionic groups and the strengthened hydrophobic association of the hydrophobic blocks in brine solutions resulted in increased salt resistance for the copolymer. However, the presence of strong anionic groups (? SO) in the macromolecules weakened the intermolecular hydrophobic association effect of the copolymer in aqueous solutions to a certain degree; that is, the strong anionic groups produced a certain negative influence on the hydrophobic association effect of the hydrophobic blocks. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 714–722, 2005