有机磷阻燃剂HDP与HMP在聚碳酸酯中的应用

研究高熔点环保型有机磷阻燃剂对苯二酚双(二苯基磷酸酯)(HDP)与对苯二酚双[二(1-甲基-2-苯基)磷酸酯](HMP)在聚碳酸酯(PC)中的应用。结果表明,当阻燃剂质量分数为7%时,PC/HDP与PC/HMP的极限氧指数测试(LOI)值分别为30.4与30.6,相对于PC(28.0)有较大提升,并且垂直燃烧测试(UL-94)都通过了V-0级,拉伸强度提升约3.5 MPa,弯曲强度提升约8 MPa。热重(TG)曲线和热重微分(DTG)曲线表明,HDP与HMP都降低了PC材料的最大热分解速率,同时PC/HDP的成碳效果优于PC/HMP。     

Microemulsion formation and detergency with oily soils: III. Performance and mechanisms

The objective of this study was to investigate the correlation between oily soil removal efficiency and low oil-water interfacial tension (IFT) generated by microemulsion formation. A mixture of sodium dioctyl sulfosuccinate, alkyl diphenyl oxide disulfonate, and sorbitan monooleate was selected as a detergent formulation to evaluate detergency performance for two highly hydrophobic oils: hexadecane and motor oil. The maximum detergency corresponds to formation of a Winsor Type III microemulsion as well as to the supersolubilization region, which is a Winsor Type I microemulsion close to the Winsor Type III region. In addition, the oil removal in the rinse step is almost as high as that in the wash step for both regions. We propose the following mechanism to explain these results: During the wash step, the contact angle of the oil on the fabric surface is progressively increased, resulting in the detachment of the oil droplets. However, owing to the very low IFT, the spreading effect is dominant, thereby causing incomplete oil removal. During the subsequent rinse step, the IFT increases, passing through a composition at which the rollup mechanism causes additional oil removal. These results demonstrate that microemulsion formation and the resulting IFT reduction are important mechanisms in oily soil detergency.     

草酸二乙酯与苯酚酯交换反应产物的气相色谱-质谱分析

采用气相色谱-质谱联用(程序升温)的方法,对MoO3/SiO2催化剂催化草酸二乙酯与苯酚酯交换反应的反应产物进行了分析.结果表明,草酸二乙酯与苯酚酯交换反应生成草酸二苯酯、乙基苯基草酸酯两种反应产物.     

Complete devulcanization of sulfur‐cured butyl rubber by using supercritical carbon dioxide

Sulfur‐cured butyl rubber was devulcanized completely in supercritical CO₂ by using diphenyl disulfide (DD) as a devulcanizing reagent. The optimum devulcanizing conditions were studied and the sol fraction of the reclaimed rubber obtained was up to 98.5%. The possible devulcanizing mechanism was investigated. Then, the sol component of reclaimed rubber was characterized by gel permeation chromatography, ¹H‐NMR, and differential scanning calorimetry, and the reclaimed rubber was characterized by TGA. Because of the substitution of a large portion of allylic hydrogen by sulfurated functional groups during vulcanization, the signal of the olefinic proton shift. As a result of the numerous decreases in the active crosslinking sites and the remaining DD, reclaimed rubber could not be cured by sulfur. At last, the blends of virgin butyl rubber and different contents of reclaimed rubber were revulcanized and their mechanical properties investigated. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A new process for the synthesis of diphenyl carbonate from dimethyl carbonate and phenol over heterogeneous catalysts

The two-step synthesis of diphenyl carbonate (DPC) from dimethyl carbonate (DMC) and phenol has been compared in liquid phase and gas phase, both over heterogeneous catalysts. In the first step, equilibrium yields of methyl phenyl carbonate (MPC) in the transesterification of DMC and phenol were very low at low temperatures in the liquid phase although reaction rates were fast. This endothermic reaction was more favorable at high temperatures in the gas-phase reaction. Titanium oxide catalysts supported on SiO₂ or activated carbon were found to be effective in a continuous gas flow reactor. In case of the second step, the disproportionation of MPC, selective formation of DPC was not feasible in the gas-phase reaction due to extensive side reactions. However, there was no by-product in the liquid-phase reaction over the TiO₂/SiO₂ catalyst. Therefore, our proposed two-step synthesis process consists of the gas-phase transesterification of DMC and phenol followed by the liquid-phase disproportionation of MPC to DPC, both over the TiO₂/SiO₂ catalyst. This revised version was published online in July 2006 with corrections to the Cover Date.     

碳酸乙烯酯与醋酸苯酯合成碳酸二苯酯的热力学分析

采用Benson基团贡献法计算了碳酸乙烯酯与醋酸苯酯酯交换反应相关物质的标准摩尔生成焓、标准摩尔熵和等压摩尔热容;计算了373～473 K反应温度内由碳酸乙烯酯和醋酸苯酯合成碳酸二苯酯反应体系中涉及到的主副反应焓变、熵变、吉布斯自由能变和平衡常数.计算结果表明,该反应为放热反应,升高温度不利于碳酸二苯酯的生成;合成碳酸二苯酯的酯交换反应为自发过程,而热力学平衡常数较小.为提高碳酸二苯酯的收率,需要开发高效的催化剂和深入研究反应工艺.     

立式联苯炉风机供热系统改造

联苯炉是向聚合工艺提供热量的加热装置,与卧式联苯炉相比,立式联苯炉的热效率较低.通过对联苯炉风机预热器的改造,提高了立式联笨炉的热效率,达到了节能降耗的目的.     

Modelling the vertical UL 94 test: competition and collaboration between melt dripping,gasification and combustion

An experimental and numerical investigation of the effect of bisphenol A bis(diphenyl phosphate) (BDP) and polytetrafluoroethylene (PTFE) on the fire behaviour of bisphenol A polycarbonate/acrylonitrile butadiene styrene (PC/ABS) in the vertical UL 94 scenario is presented. Four PC/ABS blends were discussed, which satisfy different UL 94 classifications due to the competing effects of gasification, charring, flame inhibition and melt flow/dripping. For numerical investigation, the particle finite element method (PFEM) is used. Its capability to model the complex fire behaviour of polymers in the UL 94 is analysed. The materials' properties are characterised, in particular the additives impact on the dripping behaviour during thermal exposure. BDP is an efficient plasticiser; adding PTFE prevents dripping by causing a flow limit. PFEM simulations reproduce the dripping and burning behaviour, in particular the competition between gasification and dripping. The thermal impact of both the burner and the flame is approximated taking into account flame inhibition, charring and effective heat of combustion. PFEM is a promising numerical tool for the investigation of the fire behaviour of polymers, particularly when large deformations are involved. Not only the principal phenomena but also the different UL 94 classifications and the extinction times are well predicted. Copyright © 2014 John Wiley & Sons, Ltd.     

Surface Chemical Properties and Micellization of Disodium Hexadecyl Diphenyl Ether Disulfonate in Aqueous Solution

The surface tension of disodium hexadecyl diphenyl ether disulfonate (C₁₆‐MADS) was measured at different NaCl concentrations (0.00–0.50 mol L^?1) and temperatures (298.0–318.0 K) using the drop‐volume method. The results show that, with increasing temperature, the critical micelle concentration (CMC) of C₁₆‐MADS increases slightly, but the maximum surface adsorption capacity (Γ_max) at the air–water interface decreases. When the concentration of NaCl was increased from 0.00 to 0.50 mol L^?1, the CMC of C₁₆‐MADS decreased from 1.45 × 10^?4 to 4.10 × 10^?5 mol L^?1, but the surface tension at the CMC (γ_cmc) was not affected. When the concentration of NaCl was increased at 298.0 and 303.0 K, the Γ_max of C₁₆‐MADS increased. When the temperature was increased from 308.0 to 318.0 K, the surface excess concentration (Γ_max) of C₁₆‐MADS abnormally decreased from 2.26 to 1.41 μmol m^?2 with increasing NaCl concentration. The micellization free energy () decreased from ?63.98 to ?76.20 kJ mol^?1 with increase of temperature and NaCl concentration. The micellar aggregation number (N_m) of disodium hexadecyl diphenyl ether disulfonate (C₁₆‐MADS) was determined using the molecule fluorescence probe method with pyrene as probe and benzophenone as quencher. The results show that an appropriate N_m could be measured only at surfactant concentration above the CMC. The N_m increased with an increase in C₁₆‐MADS concentration, but the micropolarity in the micelle nucleus decreased. The temperature had little effect on N_m. Compared with typical single hydrophilic headgroup surfactants, aggregates of C₁₆‐MADS exhibit different properties.     

多溴联苯醚（PBDEs）的降解技术研究进展

多溴联苯醚（Polybrominated Diphenyl Ethers,简称PBDEs）作为一种新型的持久性有机污染物,因其在环境中的广泛分布和生物累积性而备受关注。因此,研究降解多溴联苯醚经济适用的方法和机理具有十分重要的现实意义。文章针对当前国内外学者对环境中多溴联苯醚降解技术及机理的研究进展,分别阐述了生物降解、光降解、电解Fenton试剂及零价铁法的降解效果及降解机理,并总结了今后多溴联苯醚降解技术的研究方向。