Activated carbon from solid wastes using a pilot-scale batch flaming pyrolyser

Activated carbon has been prepared from solid wastes carbonised in a pilot-scale batch flaming pyrolyser. Wood furniture waste (chipboard and plywood), scrap tyres, urban sewage, and straw were selected as pollutant solid wastes for this study. Burn-off levels, porosity, and BET surface were determined. From furniture waste derived char, a highly microporous solid was obtained at 850°C with a BET surface area of 855 m²/g. A medium surface area (431 m²/g) activated solid was obtained from tyre derived char at 1000°C. An FT-IR spectroscopic study of activated tyre and furniture derived chars showed different chemical structures and a higher water adsorption capacity for furniture derived solids than for those derived from tyres. The low cost flaming pyrolyser can produce, at pilot scale, chars suitable for activation from furniture wastes and tyres.     

Synthesis, characterisation and decomposition of 1,3-benzene disulfonyl azide; a cross-linking agent for polyolefins

We have studied the thermal decomposition of 1,3-benzenedisulfonyl azide (1,3-BDSA), and verified that sulfonyl nitrenes formed are able to cross-link polyolefins, including PP. The decomposition was studied with DSC, TGA, and the GC–MS analysis of gaseous products. Both the decomposition of pure 1,3-BDSA and 1,3-BDSA dissolved in a polyolefin were studied. Decomposition occurs by loss of nitrogen giving sulfonyl nitrenes. In the polyolefin nitrenes cross-links the carbon chains by C–H insertion. Cross-linking of PP was verified with SEC. SEC showed no signs of decomposition of PP. Decomposition in the polyolefin was a first order reaction with a half-life of 25.7 s at 200 °C. Hence, 1,3-BDSA is suited for processing with polyolefins. Decomposition of pure 1,3-BDSA is more complicated with unwanted products such as SO₂ and benzene being formed, thereby emphasising the need for good blending when used in polyolefins.     

Quantitative gas chromatography,using retention times

Diffusion of an injected sample within a gas chromatographic column does not begin from a point source but from a band. Therefore the method of calculating relative areas by using retention time × peak height may require a correction factor to give a more accurate estimate of peak areas. When this correction was applied, the analysis was comparable with that obtained by the more time-consuming triangulation method.     

Separation of polyolefins based on comonomer content using high‐temperature gradient adsorption liquid chromatography with a graphitic carbon column

This report describes the application of a recently developed polyolefin characterization tool based upon gradient adsorption high‐temperature liquid chromatography (HT‐LC) using a graphitic carbon stationary phase to polyolefin homopolymer and previously unreported copolymer systems. Polyolefin‐based materials find utility in a broad range of applications and are differentiated by parameters such as molecular weight and comonomer content. Polymer comonomer distribution is commonly determined by crystallinity‐based separations (ATREF, CRYSTAF). These techniques, however, are time consuming. In addition, some semicrystalline polymers undergo cocrystallization, impacting the techniques' universal utility. Adsorption‐based HT‐LC can ideally overcome the limitations of crystallinity‐based separations, shedding new light on the composition of randomly‐polymerized polyolefins. In this report the basic separation capability of the adsorption HT‐LC technique, using a graphitic carbon column, is demonstrated for poly (ethylene‐co‐octene) and poly(ethylene‐co‐propylene) systems and compared with select precipitation/redissolution HT‐LC and ATREF results. Select results in this paper are also compared and contrasted to other recent publications on similar separations of polyolefins. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Fractionation and characterisation of bisphenol a polycarbonate by gel permeation chromatography

Bisphenol A polycarbonate was fractionated from methylene chloride solution by a progressive precipitation technique. The intrinsic viscosities of these fractions were obtained in methylene chloride solution and corresponded to a viscosity average molecular weight range of 2 × 10³ to 80 × 10³. The fractions were used to calibrate a gel permeation chromatograph, an experimental Q-factor of 23.8 was found. The calibration was further confirmed by membrane osmometry and light scattering experiments. The experimental viscosity data demonstrated that the Kurata-Stockmayer-Roig relationship is suited to interpret the molecular expansion of polycarbonate in methylene chloride.     

Preparation of syndiotactic polyolefins by using metallocene catalysts

Summary Polyolefins having syndiotactic structure were obtained by using 1-methyl-1-ethylidene-(cyclopentadienyl-1′-fluorenyl) zirconium dichloride and methylaluminoxane as a catalyst. 1-Butene and 4-methyl-1-pentene gave crystalline polymers having syndiotactic structure, while 1-pentene, 1-hexene and 1-octene gave noncrystalline polymers having syndiotactic structure. The identification of syndiotactic and isotactic polyolefins was made by ¹³C-NMR, X-ray diffraction, and differential scanning calorimetry.     

Kinetic studies on bismaleimide polymerization using inverse gas chromatography

Kinetics of polymerization of 4,4′-bismalemidodiphenyl methane (BMI) were studied in the temperature range of 158–222°C by inverse gas chromatography (IGC) technique. BMI was synthesized and purified and then coated on DMCS treated chromosorb for preparation of GC column. Retention behavior of dimethyl formamide was studied at different temperatures and at different time intervals to follow the phase changes and kinetics of polymerization, respectively. The kinetic data obtained by IGC were compared with those obtained by differential scanning calorimetry. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1613–1619, 1997     

All-glass system for preparative gas chromatography using capillary columns

A zero dead-volume all-glass-lined stainless-steel effluent splitter with a modified thermal gradient collector was designed for preparative gas chromatography using glass capillary columns. This system gives efficient collection of extremely pure samples of the 1-ng to 10-g range for spectral analysis and biological testing.Approved as TA 15656 by the director of the Texas Agricultural Experiment Station in cooperation with ARS, USDA. Supported by the Texas Department of Agriculture interagency agreement IAC-0487 (78-79).     

The weathering degradation of polyolefins

The mechanism of weathering degradation of polyolefins is discussed. Variations in spectral radiation, temperature, density, polymer absorption spectra, orientation, and sample thickness are related to property deterioration. Organic ultraviolet stabilizers, zinc oxide stabilization, and UV catalyzed degradation are briefly reviewed.     

Solubility behaviour of polystyrene: thermodynamic studies using gas chromatography

Studies of thermodynamic parameters and solution properties of polystyrene with various solvents have been performed by gas-liquid chromatography (g.l.c.). A range of solvents has been selected for this purpose. Experiments were performed at 162.31°C, 171.84°C, 219.77°C and 229.43°C. From the chromatographic retention data obtained at these temperatures, the solubility behaviour of polystyrene with each of the solvents selected has been observed and the Flory-Huggins interaction parameters, infinite dilution activity coefficients and heats of solution were determined. The glass transition temperature of polystyrene was determined experimentally.     

The analysis of glycerol by gas chromatography

Commencai glycerol and its organic impurities can be measured accurately by a single gas Chromatographic GC analysis utilizing Tenax-GC® and flame detection.     

Characterization of soapstock and deodorizer distillates of vegetable oils using gas chromatography

Soapstock and deodorizer distillates are complex lipid mixtures that are produced in significant amounts by the vegetable oil refining process. These mixtures contain components such as fatty acids, sterols, squalene and tocopherols that have important commercial value and therefore their characterization and quantification are of interest. We describe here the development of a simple gas chromatography (GC) method based on a silylation derivatization technique coupled with the use of a medium polar column to separate the different classes of fatty compounds in these waste streams. This method is suitable for GC coupled with either a flame ionization detector or a mass spectrometer.     

新型搅拌棒式微萃取器萃取气相色谱法分析蔬菜中毒死蜱残留量

用自制新型搅拌棒式微萃取器吸着萃取、溶剂解吸,结合配有电子捕获检测器（ECD）的气相色谱分析蔬菜中毒死蜱残留量,以此建立一种快速、简单而准确的分析方法。对影响萃取的重要参数如萃取时间、解吸时间、解吸溶剂等进行了优化。该方法在1-500ng／L有很好的线性,线性相关系数为0．9914,最低检测限为0．3ng／L。用50ng／L的毒死蜱标准品做重现性实验,其RSD低于6．7％（n=5）。并对实际蔬菜样品进行了分析,结果令人满意。     

Decreasing the combustibility of polyolefins using microencapsulated fire retardants

A method of decreasing the combustibility of polyolefins by incorporation of microencapsulated fire retardants (ME FR) in the polymer melt was developed. It was found that PE and PP containing ME FR in PE and polyvinyltriethoxysilane (PVTES) shells belong to the category of difficult to burn materials. The study of the thermophysical and physicochemical characteristics of modified PE and PP demonstrated the major possibility of realization of the method for fabrication of polyolefins with a low fire hazard. The study was conducted with the financial support of the RF Ministry of Defense (project code 95-22-6.3.-99). Deceased. We would like to thank Prof. M. S. Vilesovaya in whose laboratory the MPAA was encapsulated. Translated from Khimicheskie Volokna, No. 3, pp. 12–14, May–June, 1997.     

Reactive compatibilization of polyolefins using low molecular weight polybutadiene

Compatibilization of polyolefins using a combined system consisting of a low molecular weight liquid polybutadiene (l-PB) and a free radical initiator has been investigated. Binary blends LDPE/HDPE and LDPE/PP as well as ternary blends LDPE/HDPE/PP were prepared by reactive blending in the chamber of a Brabender Plasticorder. Transmission electron microscopy has been used for determination of phase structure of the final blends. Tensile impact strength of these materials, as the main criterion of compatibilization efficiency, was determined by a standardized method. A significant improvement in tensile impact strength of the compatibilized blends and considerable changes in their morphology have been found. The increase in tensile impact strength was apparently attained due to formation of effective linkages between main polymer components with the help of polybutadiene chains, providing good adhesion at the interface. Because the permanent thermoplasticity of these materials has been proved by repeated processing, any stable network based on covalent bonds in these blends cannot be considered. The used procedure shows to be a promising way for the recycling of commingled polyolefin waste as well as for the preparation of special polyolefin blends from virgin polymers.     

运用反气相色谱测定聚氯乙烯树脂脱吸速率

为了改进聚氯乙烯颗粒内部结构,运用反气相色谱技术测定聚氯乙烯树脂内部结构,测定其脱吸速率,得到容易脱吸氯乙烯单体的聚氯乙烯树脂。以氯乙烯(VCM)作探针分子,聚氯乙烯作固定相,通过测定探针分子与固定相的相互作用来获取固定相的物理化学参数,将实验数据与双粒子模型拟合,计算出凝胶体直径d2、凝胶体含量X2、聚集体直径d1、聚集体含量X14个参数。凝胶体直径越小,含量越低,单体越容易脱附;聚集体直径越大,含量越高,越容易脱附,而聚氯乙烯树脂脱附单体能力以凝胶体影响为主,因此定义聚氯乙烯树脂脱附单体系数为d22X2,脱附系数越大,脱吸单体能力越难,反之越容易。     

Monitoring the linear alkylbenzene sulfonation process using high-temperature gas chromatography

Controlling the linear alkylbenzene sulfonate (LAS) sulfonation process is a critical part of the LAS manufacturing process; this process can be monitored by assaying for LAS content, unsulfonated linear alkylbenzene (LAB), and LAB sulfones. Traditionally, assaying the LAB and LAB sulfone contents has been time consuming and not straightforward. A simple and rapid procedure is described for the isolation and simultaneous capillary gas chromatographic (GC) quantification of LAB and LAB sulfones in LAS. The procedure involves extraction of the unsulfonated LAB and the LAB sulfones into n-heptane; sodium linear alkylbenzenesulfonate or linear alkylbenzenesulfonic acid (reacted to form sodium linear alkylbenzenesulfonate) remains in the aqueous extraction solvent layer. High-temperature capillary GC using a specialty metal capillary column enables both LAB and high molecular weight LAB sulfones to be quantified.     

大米中11种有机氯农药残留量的同时测定

用气相色谱一电子捕获检测器法 ,对我省出口大米中 1 1种有机氯农药残留量进行了测定。样品用丙酮 乙腈 ( 3 :7)混合液进行提取 ,弗罗里硅土净化 ,以DB -1 70 1毛细管柱作为分离柱 ,能有效分离 1 1种有机氯农药 ,并能去除大米基质的干扰。该法在 0 .0 0 5～ 0 .2mg/kg具有良好的线性 ,检出限为 0 .0 0 5mg/kg ,在对我省出口大米有机氯农残检测中 ,获得了较为满意的结果。     

Quantitative analysis of short chain fatty acids using gas liquid chromatography

The short-chain fatty acids, propionic to pelargonic, have been analyzed by gas liquid chromatography, as their butyl, phenacyl, and decyl esters to overcome losses due to their volatility. The three methods are compared and the decyl ester procedure offers the most advantages. Presented in part at the AOCS meeting in Los Angeles, Calif., 1959. Issued as N.R.C. No. 7261. National Research Council of Canada Postdoctorate Fellow 1957–1959.