酸性废水内衬HDPE长输管道设计实践

瓮福(集团)在国内同行业中首次采用酸性废水代替硫酸作选矿调整剂新工艺和内穿插管道输送技术,节约了硫酸和水的消耗。选择单级泵站和钢衬HDPE管设计将酸性废水长距离输送到选矿厂循环使用,实现了水系统的封闭循环,符合国家循环经济和资源的综合利用政策,具有明显的经济效益和环境效益。     

炭黑填充HDPE的力学性能和微波加热性能

为了提高HDPE（高密度聚乙烯）的微波加热性能,将炭黑和HDPE共混制备了复合试样,测试了试样的微波加热性能和机械性能,并用扫描电镜（SEM）观察了试样的断面形态。结果表明,当试样中炭黑用量超过一个临界值后,试样的升温速率随着炭黑用量的增加而显著上升。该临界值和作用微波的功率有关,当微波功率为100W时,临界炭黑的质量分数为9％,200W时为7％,400W时为3％。试样的拉伸强度和模量在炭黑的质量分数低于13％时保持不变,在超过13％后,拉伸强度和模量随着炭黑用量的增加而升高。试样的断裂伸长率在炭黑的质量分数小于7％时保持不变,在炭黑的质量分数超过7％以后下降非常快。     

HDPE及增韧HDPE的力学性能与测试条件的关系

于23℃时,研究了拉伸、弯曲速度及试样缺口剩余宽度对高密度聚乙烯(HDPE)、HDPE/弹性体、HDPE/E型增韧母料(E-TMB)的拉伸、弯曲及冲击强度等力学性能的影响。结果表明,所研究的测试条件对这三种材料力学性能影响的程度不同:对于这三种材料,均是拉伸速度对拉伸屈服应力、弹性模量影响的程度较小,对断裂伸长率影响的程度较大,弯曲速度对弯曲弹性模量、弯曲强度影响的程度较大;三种材料中,拉伸速度对断裂伸长率影响程度最大的是HDPE/弹性体,最小的是HDPE/E-TMB,弯曲速度对弯曲弹性模量、弯曲强度影响程度最大的是HDPE/E-TMB,最小的是HDPE/弹性体;随外力作用速度增大性能并非匀速变化,对不同的材料、不同的性能有相应的敏感区;试样缺口剩余宽度对HDPE/E-TMB的悬臂梁缺口冲击强度影响程度较大,而且缺口剩余宽度由7.8mm增加到8.0mm是影响的敏感区,对HDPE、HDPE/弹性体的影响的程度很小。     

Biodiesel influence on tribology characteristics of a diesel engine

This paper deals with the influence of biodiesel on some tribology characteristics of a bus diesel engine with a mechanically controlled fuel injection system. The tests have been performed on a fully equipped engine test bed, on a fuel injection test bed and on a discharge coefficient testing device. The tested fuel was neat biodiesel produced from rapeseed. Attention was focused on the biodiesel influence on the pump plunger surface roughness, on the carbon deposits in the combustion chamber, on the injector and in the injector nozzle hole. The pump plunger surface was analyzed by experimentally determined roughness parameters and by a microscope. The carbon deposits at fuel injector and in the combustion chamber were examined using endoscopic inspection. The deposits in the injector nozzle were investigated indirectly by measuring the nozzle discharge coefficient. Numerical simulation has been performed in order to estimate the influence of the discharge coefficient variation on the computed injection characteristics. The obtained results indicate that biodiesel usage may even improve the pump plunger lubrication conditions. Furthermore, the carbon deposits in the combustion chambers did not vary significantly in quantity but they were noticeably redistributed. Finally, it was found out that the variation of the nozzle discharge coefficient has to be taken into account only if high accuracy of numerical simulation is desired.     

Effect of CNT-coated carbon fibres in HDPE composites

The mechanical properties of thermoplastic HDPE composites filled with CF and CNT were studied. Coupling agent surface-treated CF-filled HDPE composites increased their tensile strength and impact strength, which is further increased with the addition of CNT. Coupling agent was proved to play an important role in the improvement of the interfacial adhesion of the CF/HDPE composite. SEM showed that CNT coating-treated CF/HDPE composites show better dispersion of the ?ller into the matrix.     

Morphological evolution of HDPE parts in the microinjection molding: Comparison with conventional injection molding

To compare the difference of morphological evolution of HDPE micropart and macropart, micropart with 200 μm thickness and macropart with 2000 μm thickness were prepared. The PLM images of micropart and macropart exhibited a similar “skin–core” structure, but the micropart showed a much larger fraction of orientation layer. The SEM observation of core layer of micropart featured an unoriented lamellae structure and shear layer of micropart showed a highly oriented shish‐kebab structure. The 2D‐WAXD patterns of shear layer of macropart indicated twisted oriented shish‐kebab (KM‐I) structures, however that of micropart indicated untwisted oriented shish‐kebab (KM‐II) structures which was firstly found in microinjection molding. The diffraction pattern of the micropart exhibited stronger azimuthal dependence than the shear layer of macropart, indicating the most pronounced orientation of HDPE chains within lamellae. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

PA6／HDPE／EVA三元共混改性的研究

研究了PA6/HDPE、PA6/HDPE/EVA共混物的密度、热性能和力学性能。PA6/HDPE/EVA三元共混物的力学性能比PA6/HDPE二元共混物有明显提高。对于拉伸强度,EVA的最佳含量在2～4份。冲击强度随EVA含量的增加而提高,EVA的含量小于5份时,对共混物的硬度几乎没有影响。     

几种钢包用含碳耐火材料对IF钢增碳的比较

通过感应炉试验分析了钢包渣线用3种碳含量不同的镁碳砖(C的质量分数分别为8.3%、15.5%和17.9%),钢包底用蜡石-碳化硅砖(C的质量分数为3.71%)以及实验室开发的MgO-Al2O3-SiC质钢包渣线浇注料(C的质量分数为4.07%)对IF钢增碳的影响,并对其增碳的机理进行了初步分析讨论。试验结果表明:渣线镁碳砖的碳含量越高,对IF钢造成的增碳量越大;包底蜡石-碳化硅砖对IF钢水的增碳量达到渣线镁碳砖的7.73倍;MgO-Al2O3-SiC质浇注料也对IF钢产生明显的增碳效果,不宜用作冶炼超低碳钢的钢包渣线材料。     

烯基双酚A醚接枝LDPE对HDPE／PC相容性和结晶速率的影响

本文通过热力学曲线,对HDPE/PC体系中HDPE的熔融温度(T_m)和PC的玻璃化转变温度(T_g)的测试,考察了增容剂烯基双酚A醚接枝LDPE(LDPE-g-DBAE)对共混体系相容性的影响,同时还研究了体系中HDPE的结晶速率。     

碳纳米管/HDPE复合材料的制备及性能研究

将酸化处理以后的碳纳米管（CNTs）与高密度聚乙烯（HDPE）复合,采用机械共混法制备了定向CNTs／HDPE复合材料,并对其力学性能、相态结构、流变性能及热性能进行了研究。结果表明：CNTs的加入,提高了复合材料的屈服强度和拉伸模量,但同时却降低了材料的断裂强度和断裂伸长率;CNTs在HDPE基体中有了较好的分散性和相容性;CNTs的加入对复合材料流变性能产生了较大的影响,加入少量的CNTs可以使复合材料体系的表观粘度降低,有利于HDPE加工性能的改善;CNTs加入后,HDPE的熔融温度和结晶熔融焓均有所下降。     

Stainless steel coupled with carbon nanotube-modified epoxy and carbon fibre composites: Electrochemical and mechanical study

The aim of this work is the study of the electrochemical and mechanical behaviour of stainless steel (SS304) adhesively bonded with carbon nanotube (CNT)-reinforced epoxies to either SS304 or carbon-reinforced composites substrates. For metal to metal (MtM) joints, the shear strength of nano-reinforced adhesives was studied using single lap shear specimen geometries. The lap shear strength was improved by almost 50% and the highest shear strength appeared for 0.6% CNT weight content in the adhesive. The metal to composite joint performed altogether better compared to the MtM joint, although the CNT inclusion had an adverse effect on the lap shear strength attributed to the physical property change of the epoxy. Although the incorporation of CNTs was found to increase the galvanic effect, it also enhanced corrosion protection, as the modified adhesives exhibited increased resistance to uniform corrosion and localised corrosion and prevented the electrolyte from reaching the substrate.     

HDPE和NBR共混改性及其工艺条件的研究

研究了三种牌号的ＨＤＰＥ（８９００Ｓ、５０００Ｓ、５０７０ＥＡ）与两种牌号的ＮＢＲ（ＮＢＲ—１８,ＮＢＲ－２６）改性的共混体系。结果表明：用极性ＮＢＲ改性非极性ＨＤＰＥ,其改性效果除了与ＮＢＲ的牌号、含量和基体树脂ＨＤＰＥ的熔体指数有关之外,还与混炼时间、温度、辊距等工艺条件有关,并讨论了对体系冲击性能的影响。     

高密度聚乙烯/石墨/碳纤维导热复合材料性能的研究

采用高密度聚乙烯(HDPE)、石墨、碳纤维制备高导热、高强度的复合材料。通过SEM照片考察高密度聚乙烯/石墨/碳纤维复合体系的微观结构;研究石墨及碳纤维的加入是否可以形成导热通道以及随着石墨的添加量的提高,复合材料的导热性能及其力学性能的变化。结果表明:当石墨的质量分数为60%,碳纤维的质量分数为5%时,复合材料的导热系数达到7.938 W/(m.K),是纯HDPE的20倍。     

Interaction of mechanical and electrochemical factors in erosion-corrosion of carbon steel

The interaction of mechanical and electrochemical factors in the erosion-corrosion process of carbon steel A1045 was investigated in Na₂SO₄ solution/silica sand slurry with a rotating cylinder electrode system. In line with the mechanism associated with material wastage, the synergism due to the interaction of erosion and corrosion was divided into corrosion-enhanced erosion and erosion-enhanced corrosion. The electrochemical experimental results indicated that the carbon steel showed active dissolution behavior, and the corrosion process was not controlled by the mass transfer when the rotating velocity is high enough. Scratching electrode tests and tensile tests were conducted to simulate the effect of sand impingement on corrosion process. Results showed that the impingement of the solid did not affect the corrosion behavior significantly in the present system. For the effect of corrosion on erosion, a half-logarithm relationship was found between weight loss due to corrosion-enhanced erosion and the applied anodic current density. According to a chemo-mechanical model, this effect can be attributed to the hardness degradation in metal surface with corrosion current.     

HDPE和MVQ导热性的影响因素

对高密度聚乙烯（HDPE）、HDPE／导热填料和硅橡胶（MVQ）／导热填料三种材料的导热性能进行了试验研究。总结分析了导热填料种类及含量、温度、结晶度、密度等方面因素对材料导热性能的影响。实验结果表明：HDPE材料的热导率随着结晶度的增大而上升；随着导热填料粒径的增加，HDPE、MVQ材料的热导率增大；材料密度的提高，可提高导热性能。     

Passivity and pitting of carbon steel in chromate solutions

The passivity and pitting behavior of A516-70 carbon steel in chromate solutions were studied using electrochemical measurements. The anodic Tafel slopes in the active region show that carbon steel dissolution involves two mechanisms in this range: formation and further oxidation of a pre-passive film of Fe(OH)₂. The first current peak at −0.228 V (Ag | AgCl) in cyclic voltammograms is caused by the oxidation of the pre-passive film and the formation of a stable passive film of Cr³⁺+Fe³⁺. The second peak at 0.612 V is ascribed to the oxidation of Cr³⁺ in passive film to Cr⁶⁺. The charge-transfer step at the electrode/solution interface controls the film formation and dissolution; the role of diffusion is negligible. Chromate ions play a prominent role in the formation of passive film, but hardly affect the stability of the passive state. More chromate ions in solution enhance the dissolution of Cr³⁺ at the second peak potential. Upon addition of chloride ions metastable pits are initiated, as indicated by a typical current transient: a quick current rise followed by a slow recovery. A maximum exists in the potential dependence of the pit initiation rate. Metastable pit growth is controlled by the ohmic potential drop mainly across the cover over the pits. Increasing potential is beneficial to the repassivation of metastable pits, as indicated by the decreasing average repassivation time. A pit stabilization criterion, the ratio of peak pit current to pit radius, must exceed 6×10⁻² A cm⁻¹ during pit growth to avoid repassivation in the present system.     

HDPE3300F性能特点及加工工艺

HDPE3300F是燕化公司近年开发的新产品,主要用于生产包装薄膜,本文就其特点及加工工艺进行了研究。     

不同细度滑石粉填充HDPE的研究

本文研究了不同细度滑石粉填充HDPE体系的力学性能。结果表明;随着滑石粉细度的增加,填充HDPE的拉伸强度和拉伸模量提高了,经偶联剂处理后的滑石粉的填充效果,明显优于未处理的。其中2500目滑石粉的填充效果最佳     

12-Aminododecanoic acid as a corrosion inhibitor for carbon steel

The inhibiting effect of 12-aminododecanoic acid (AA) on corrosion of carbon steel (CS) was investigated in hydrochloric acid of different pH, temperatures and over a prolonged period of time, and also in some other selected corrosive solutions. It was found that AA inhibits both partial corrosion reactions, with a slightly stronger inhibition of the anodic corrosion reaction. The corrosion protection mechanism is by formation of a surface-adsorbed AA monolayer that offers a hydrophobic barrier to transport of solvated corrosive ions to the surface. A maximum inhibition efficiency of 98.8 ± 0.5% was achieved in 0.5 M HCl. The adsorption of AA onto the CS surface was described by the Langmuir adsorption isotherm. The corresponding standard Gibbs energy of adsorption was calculated to be −26 kJ mol⁻¹. Polarization modulation infrared reflection absorption spectroscopy measurements revealed that the adsorbed AA monolayer is amorphous, which is due to the high heterogeneity of the CS surface.     

Total Acid Number Determination of Biodiesel and Biodiesel Blends

The repeatability and accuracy of the total acid number (TAN) measurement for soy oil-based biodiesel–diesel blends using the ASTM D664 method was studied. ASTM D664 is the standard reference method for measuring the acid number of both biodiesel and petroleum-derived diesel, which specifies procedures for the determination of acidic components in biodiesel and diesel, and claims good repeatability and mediocre reproducibility during application, but cites no information on accuracy. However, the accuracy of this method is very important for setting the specifications for biodiesel blends, especially for B20 (a mixture composed of 20% biodiesel with 80% diesel) because of its wide commercial production. The accuracy of ASTM D664 was measured to be within 4.13% for B20 in the acid number range of 0.123–0.332 mg KOH/g. The maximum repeatability was approximately 5.21% at an acid number of 0.123 mg KOH/g. Within the ASTM D6751-07b specification for TAN (0.5 mg KOH/g), good accuracy and repeatability were also obtained. Accuracy specification and electrode operation suggestions for ASTM D664 are also given.