一种新型含溴磷酰胺酯阻燃剂的合成

以三氯氧磷、季戊四醇、氨气等为原料合成了一种未见文献报道的含磷、溴、氮阻燃剂1,3 (2,2 二溴甲基)丙撑 O (2,6,7 三氧杂 1 氧基磷杂双环[2.2.2]辛烷 4 亚甲基)磷酰胺酯,通过元素分析、红外光谱等确定了化合物的结构 通过TG初步探讨了其热稳定性     

Synthesis and properties of polyoxyarylenesiloxanes

High molecular weight polymers containing oligosiloxanes in the backbone were made by the reaction of aromatic diols with α,ω-diaminosiloxane homologs. The glass transition temperatures dropped by 30–40°C in a homologous series with each siloxane added. The thermal stability also suffered when increasing the number of siloxane groups. The polymers all displayed high % char measurements and one polymer (disiloxane) tested had a V₀ rating by UL-94 testing. The trisiloxane-containing polymer had a high percent elongation at break (>300%). All the polymers tested were fairly susceptible to hydrolysis. © 1994 John Wiley & Sons, Inc.     

Reaction of melamine phosphate with pentaerythritol and its products for flame retardation of polypropylene

Due to being halogen‐free, non‐toxic, non‐erosive and environmentally friendly, melamine‐based flame retardants are attracting more and more attention. As a melamine‐based intumescent flame retardant, in this study the melamine salt of pentaerythritol phosphate (MPP) was prepared from melamine phosphate (MP) and pentaerythritol (PER). The reaction of MP with PER was then systematically investigated. The reaction product MPP was utilized to flame‐retard polypropylene (PP). FT‐IR, TGA and DSC were used to characterize MPP and also to investigate the reaction of MP and PER in depth. The experimental results show that MPP has good thermal stability and matched decomposition temperature with that of PP, making it suitable for flame retarding of PP. Also, MPP is melting‐blendable due to its softening during the heating process. The structure of MPP at a MP:PER molar ratio of 2.0 was confirmed as the same to that of the product synthesized from phosphorus oxychloride, pentaerythritol and melamine. The reaction of MP with PER was greatly influenced by the MP:PER proportion, reaction temperature and reaction time, rather than the physical state of PER, and the reaction mechanism of MP with PER was proposed. The prepared flame‐retarded polypropylene composite with 35 wt% intumescent flame‐retardant MPP has a flame retarding level of 3.2 mm UL 94 V‐0, tensile strength 27.0 MPa, Young's modulus 2442 MPa and Izod notched impact strength 3.8 kJ/m². Copyright © 2007 John Wiley & Sons, Ltd.     

增感效应导数火焰原子吸收光谱测定金属铜和铜合金中的微量铬

提出了增感效应导数火焰原子吸收光谱测定金属铜和铜合金中微量铬的新方法。研究了表面活性剂十二烷基硫酸钠对铬的增感效果。导数技术与增感效应相结合的可使火焰原子吸收光谱的灵敏度提高６８倍。本法测定金属铜和铜合金中的微量铬取得了满意效果。     

Thermal properties of compounds possessing both solid-phase and gas-phase flame retardant potential

Effective additives are required to impart a measure of fire retardancy to polymeric materials used in a variety of applications. Traditionally, these have been gas-phase active additives, most commonly organohalogen compounds, or solid-phase active agents, often organophosphorus compounds. Organosphosphorus flame retardants are often very effective but may suffer from a cost disadvantage when compared with their organobromine counterparts. Organohalogen flame retardants are usually quite effective but their use is subject to several environmental concerns. The development of additives that could simultaneously promote both types of fire retardant action could make available flame retardants that are both more cost effective and more environmentally friendly than those currently in use. Several sets of compounds including bromoanilino triazine derivatives and bromoaryl phosphates with the potential to display both solid-phase and gas-phase flame retardant activity have been prepared and evaluated by a variety of thermal methods.     

固载硫杂杯芳烃树脂分离富集-火焰原子吸收法测定痕置银

报道了色谱301固载硫杂杯芳烃树脂分离预富集-火焰原子吸收光谱法测定痕量银的新方法。探讨了固载硫杂杯芳烃树脂对银的吸附原理与最佳条件。将含Ag^＋试液在pH=10、温度为23±2℃的条件下恒温震荡10min，静置10min，Ag^＋可被树脂定量富集被吸附的Ag^＋可用5mL酸性硫脲（0．15mol／L HCl＋0．15mol／L硫脲）完全洗脱，洗脱液中的银用火焰原子吸收光谱法测定。该法对银的检出限为0．17μg／L（3σ，n=11）；线性范围为0．006—3mg／L。对0．18mg／L的Ag^＋标液进行7次测定，RSD=1．53％。回收率在99．9％-105．0％之间。用于“二次资源”锌矿渣和环境水样中痕量银的测定，结果满意。     

DNA aptamers for selective identification and separation of flame retardant chemicals

Polybrominated diphenyl ethers (PBDEs) are group of chemicals which are representative persistent organic pollutants (POPs) and used as brominated flame retardants for many consumer products. PBDEs were phased out since 2009 but are still frequently observed in various environmental matrices and human body. Here, we report ssDNA aptamers which bind to BDE47, one of the PBDE congeners commonly found in various environmental matrices, and show affinity to other major tri-to hepta- BDE congeners. The PBDE specific aptamers were isolated from random library of ssDNA using Mag-SELEX. Two out of 15 sequences, based on their alignment and hairpin loop structures, were chosen to determine dissociation constant with BDE47 and showed from picomolar to nanomolar affinities (200 pM and 1.53 nM). The aptamers displayed high selectivity to the original target, BDE47, and implying general specificity to PBDE backbone with varying affinities to other congeners. Further, we showed that the use of two aptamers together could enhance the separation efficiency of BDE47 and other BDE congeners when dissolved in a solvent compared to use of single aptamer. These aptamers are expected to provide a tool for preliminary screening or quick separation of PBDEs in environmental samples prior to trace quantitative analysis.     

Preparation of Polystyrene/Triphenyl Phosphate Composites by Suspension Polymerization and Melt Extrusion Method——A Comparative Study

Polystyrene (PS)/triphenyl phosphate (TPP) composites were prepared by both suspension polymerization and melt extrusion, and a comparative study of the flame retardance and mechanical properties was carried out. The results showed that suspension polymerization was a better technique than melt extrusion for obtaining good dispersity of the PS/TPP composite. The TPP nanoparticles, which were approximately 50 nm in size, were homogenously and uniformly dispersed in the PS matrix by suspension polymerization in one-step. However, the PS/TPP composite was partially agglomerated, exhibiting irregularly shaped micron-scale particles as a result of melt extrusion. In contrast to the melt extrusion, the limited oxygen index (LOI) of the PS/TPP nanocomposite by suspension polymerization increased to 22.6% from 21.8%, and time to ignition (TTI) increased by 12.3%, the peak heat release rate (PHRR) decreased by 8.5%, and the total heat release (THR) decreased by 11.0%. The mechanical properties of the PS/TPP nanocomposite by suspension polymerization also increased. The tensile strength, elongation at break, and flexural strength increased by 36.4%, 8.5%, and 108%, respectively.     

电热鼓风干燥箱解脱–火焰原子吸收光谱法测定地质样品中金的含量

建立高海拔地区电热鼓风干燥箱解脱–火焰原子吸收光谱法测定地质样品中的金的方法。高海拔地区由于大气压低,水的沸点低,使得泡塑吸附金的解脱率不高。为了得到准确的分析结果,采用电热鼓风干燥箱代替水浴锅来解脱泡塑吸附金,优化后的解脱条件:解脱温度为105℃,解脱时间为30 min,在此条件下金的解脱率为91.19%。金的质量浓度在0.00~10.00μg/mL范围内与其吸光度呈良好的线性关系,相关系数r=0.999 6,方法检出限为0.012μg/mL。测定结果的相对标准偏差为2.15%(n=7),加标回收率为96.0%~102.5%。用该方法测定国家一级标准物质,测定结果与参考值相符。该方法准确、可靠,适用于高海拔地区地质样品中金的测定。     

油气爆炸的氮气非预混抑制实验

依靠激波管可视化实验台架，完成了油气爆炸的氮气非预混抑制实验，获得了火焰前锋在氮气非预混段内衰减、熄灭过程的高速摄影照片。通过对实验数据和高速摄影照片的分析，讨论了油气爆炸氮气非预混抑制过程的超压特性和火焰行为。结果表明，采用氮气非预混手段能显著降低油气爆炸过程的超压与超压上升速率。油气爆炸的氮气非预混抑爆过程经历了惯性相持期、抑制衰减期和扩散熄灭期3个阶段。氮气分子作为第三体参与化学反应并携带走高能自由基的能量，促使链式反应向中止链大量发展，这是油气爆炸氮气非预混抑制过程的主要机理。抑制衰减期的火焰由衰减抑制区和核心区火焰构成，火焰与氮气的相互作用主要发生在衰减抑制区内。在抑制衰减期内，火焰速度的衰减可用线性公式描述。