氢氧化镁填充的VAMAC无卤低烟阻燃电缆胶料的配方与性能

在乙烯－丙烯酸酯橡胶（ＶＡＭＡＣ）无卤低烟阻燃电缆胶料配合中，主要填料氢氧化镁及其表面处理剂硬脂酸锌的用量是关键，硫化体系也较重要。胶料优化配方为：ＶＡＭＡＣ１００；２，５－二甲基－２，５－双（叔丁基过氧）己烷３．０～３．３；Ｎ，Ｎ′－间亚苯基双马来酰亚胺和三（甲基丙烯酸三羟甲基）丙酯０．８～１．０。硬脂酸锌处理过的陶土＋ＬＥＥ白滑粉５０～６０；加工助剂１２～１４；硬脂酸锌１．２～１．４；氢氧化镁４３～４７；其它６～７。胶料阻燃、低烟和物理机械性能良好，成品电缆通过ＧＢ１２６６６—９０燃烧试验，且完全满足设计和ＩＥＣ５０２（１９９４）性能要求     

采煤机电缆半导电EVA/CPE屏蔽层的研制

采煤机（屏蔽型）电缆的半导电橡胶屏蔽层的胶料配方为：乙烯－醋酸乙烯酯共聚物（ＥＶＡ）９０；氯化聚乙烯（ＣＰＥ）１０；过氧化二异丙苯１－３；三聚异氰酸三烯丙酯２－５；２０＃机油１５．０；固体石蜡８．０；环氧酯类增塑剂适量；乙炔炭黑４０－６０；高耐磨炭黑３０；轻质碳酸钙适量：抗氧剂３００＃１．５；硬脂酸盐１．０，含胶率４５％。ＥＶＡ．ＣＰＥ在开炼机上共混，胶料混炼可在开炼机上或密炼机中进行，本胶料与线芯绝缘胶料是一次挤出成型进入硫化管中硫化的。胶料及成品性能均满足ＧＢ７５９４—８７和ＧＢ１２９７２．１—９１标准。     

油舶舰艇用电缆护套的研制

根据油舶舰艇电线电缆的使用要求和原材料的性能价格比，其护套胶料的弹性体选用聚丙烯酸酯橡胶／氯化聚乙烯并用［（７０—８０）／（２０—３０）］；硫化剂选用２，５－二甲基－２，５－二（叔丁基过氧化）己烷（３．０—３．６份）；补强填充剂选用中性、耐油、耐化学药品及补强性能优良的超细滑石粉、煅烧陶土等无机填料（７０—８５份）；阻燃剂为氢氧化铝／氢氧化镁并用［（５０—６０）／（３０—４０）］，还可加入适量的三氧化二锑和三氧化钼；加工助剂有分散助剂Ｚ－２１０（４—５份）、合成酯类增塑剂ＷＢ３５０、微晶石蜡。胶料混炼采用逆混混炼工艺，分密炼（６０—７０℃）和开炼（辊温４０—４５℃）。挤出机参数为：温度：螺杆４５—５０℃，机筒５５—６０℃，机头８５—９５℃，模具１２５—１３５℃；螺杆长径比为（１８—２０）∶１，螺纹为双头等宽不等深式，硫化最好用盐浴。电缆成品性能满足ＧＢ９３３１—９０，ＧＢ１２６６６—９０及ＩＥＣ５０２（１９９４）等标准要求     

加工助剂SL—1的应用

加工助剂ＳＬ－１的应用ＳＬ－１橡胶加工助剂是与德国Ｂａｙｅｒ公司生产的加工助剂—Ａｋｔｉｐｔｅｓｔ及日本川口公司生产的ＥＸｔｏｎＬ－对相似。该产品由化工部沈阳橡胶制品研究所联合经营部监制．曾送到日本普利司通公司确认可以代替上述两种助剂产品。下面将该助...     

户外用阻燃EPDM绝缘材料的开发和应用

在１００份（质量份，下同）ＥＰＤＭ中加入Ｖａｒｏｘ４．０－４．５，阻燃剂８５－９５，填充补强剂９５－１０５，增塑剂３－４，共硫化剂１．８－２．２，制备了户外用阻燃ＥＰＤＭ绝缘材料。实验证明，该材料具有良好的物理机械性能。介电性能，加工性能和阻燃性能。经长期户外实验证实，该材料可作为户外阻燃ＥＰＤＭ绝缘材料，其性能可满足１ＥＣ５０２－１９９４的要求。     

汽车点火线绝缘式护套的研制

汽车点火线绝缘式护套的基本配合为：生胶采用氯磺化聚乙烯（ＣＳＭ４５）／乙烯－醋酸乙烯共聚物（ＥＶＡ４０）［（５５－６５）／（３５－４５）］并用体系；硫化剂为过氧化物，如１，４－双叔丁基过氧化二异丙苯；补强填充体系主要为沉淀法硫酸钡（５０－６０份），并辅之以锻烧陶土和ＬＥＥ白滑粉（共４０份左右）；防老剂体系为防老剂ＲＤ／ＤＬＴＤＰ并用体系（４．５－５．０份）；加工助剂有合成酯类增塑剂ＷＢ３５０、微晶石蜡和均化剂ＷＢ２２２（饱和脂肪酸酯）等。胶料的物理机械性能、介电性能及耐热性、耐油性、低温柔软性等满足设计及ＩＥＣ－５０２（１９９４）标准中有关１－３０ｋＶ挤包高聚物固体绝缘电力电缆的性能要求，且加工性能良好。     

合成反式—1,4—聚异戊二烯的硫化与性能

考察了交联反式－１，４－聚异戊二烯的结构与性能，结果表明，合成ＴＰＩ能用普通不饱和橡胶的硫化体系一硫磺／ＴＥＴＤ交联，随着硫磺用量的增加，交联密度提高，结晶度和结晶速度降低，相应热刺激温度降低，当硫磺用量小于０．７５份时，表现为热塑性；当硫磺用量大于２．０份时，室温下为弹性体，当硫磺用量在０．７５～２．０份范围内，为热致弹性体，可作为形状记忆材料，其热刺激温度在３０－５０℃，硫磺用量大于２份时，材     

橡胶加工助剂

介绍了橡胶加工助剂的发展史,一般分类及化学性质,对不同种类的助剂进行性能性能分析、对比,同时列举了橡胶加工助剂在胶料中的作用及对胶料物理的影响。在混炼胶中适当加入橡胶加工助剂,可提高胶料的操作性能,对胶料的物理无不良影响。     

共混型NBR/PVC耐油阻燃电缆护套料的研制

采用丁腈橡胶NBR与PVC共混胶为主体材料,添加橡胶硫化体系、阻燃剂、补强剂、防老剂等助剂,研制出了耐油、阻燃电缆护套料。其具有优良的综合性能,可用作油田电缆、煤矿阻燃电缆、船用电缆的护套材料。     

国内消息

国内消息橡胶操作助剂Ａ在武汉瑞兴化工有限公司投产橡胶操作助剂Ａ，是可取代国外同类产品的一种橡胶加工助剂。该产品无毒，无污染，在天然胶及合成胶的混炼工艺中使用，能提高填料的分散速度，降低胶料的门尼粘度。用量１．５％～２．０％，可提高混炼效率２０％以上，...     

Influence of water content on nanotubular anodic titania formed in fluoride/glycerol electrolytes

A study has been carried out of nanotubular anodic films formed on titanium at 20 V in fluoride/glycerol electrolyte, containing up to 50 vol.% water. Anodizing was terminated at a charge of 1 C cm⁻². Addition of water resulted in an increased current and significantly reduced tube length associated with increased oxygen gas evolution. Films formed in the absence of added water were amorphous by electron diffraction, whereas water addition also led to the formation of anatase and rutile. The barrier layer was relatively thin for electrolyte of low water content, due to either a voltage drop in the electrolyte close to the anode or to a change in the film composition affecting the electric field across the layer. Ribbing of the external walls of the nanotubes was more evident in the presence of water. It is suggested that dissolution of a fluoride-rich layer, which separates the nanotubes, accompanies the nanotube growth, with the dissolution allowing transient film formation at the external walls of the nanotubes when the residual layer is sufficiently thin.     

Centrifuge model tests on clay based engineered barriers subjected to differential settlements

The objective of this paper is to investigate the influence of thickness of the clay barrier and overburden pressure on the integrity of the clay barrier, which is provided in the cover system of low low-level radioactive waste disposal sites. A series of centrifuge tests were performed on model clay barrier subjected to continuous differential settlement at 40 g. The model clay barrier material has been selected in such a way that it envelopes the material characteristics of the clay barriers. The model clay barriers were moist-compacted on the wet side of its optimum moisture content. The performance of the clay barrier as an effective hydraulic barrier was monitored throughout the deformation process and attempts have been made to arrive at strain distribution along the top surface of clay barrier with the help of marker based digital image analysis. A 1.2 m thick clay barrier with a nominal overburden pressure of the order of 12.5 kPa was found to experience multiple cracking extending up to its full depth; whereas with overburden pressure of the order of 25 kPa, it was observed to have suppression of cracks. A catastrophic nature of water breakthrough was registered for a 0.6 m thick clay barrier with an overburden equal to that of a closure system of a low-level radioactive waste disposal site, once settlement ratio attains 0.6. This indicates that provision of thickness of clay barrier equal to 0.6 m may not be adequate.     

Filter Press for Electrodewatering of Waterworks Sludge

An electrodewatering filter press was designed and its performance was evaluated for basic operating parameters such as the electric field strength, time of electric field application, and changes in pressure. Dewatering efficiency improves with the increase of the electric field strength, application time, and pressure. Considering the operating costs due to energy consumption and electrode erosion, the optimal conditions were found to be 70 V/cm of electric field strength, 30 min of application time, and 588 kPa of pressure. The rate of electrodewatering doubled compared with that of mechanical dewatering (MDW) while the water content of the dewatered cake decreased by 25%. When an electric field is applied to the cake, clogging of the filter cloth becomes minimized due to electrophoretic mobility. The discharge of water from the cake porous matrix is facilitated owing to electroosmosis and thermal effect due to joule heating. As a result, the dewatering capacity of electrodewatering improves compared with the mechanical dewatering. The energy consumption of electrodewatering was about 370-450 kWh/t (dry solid), which accounts for only one tenth of the existing sludge treatment costs.     

Filter Press for Electrodewatering of Waterworks Sludge

An electrodewatering filter press was designed and its performance was evaluated for basic operating parameters such as the electric field strength, time of electric field application, and changes in pressure. Dewatering efficiency improves with the increase of the electric field strength, application time, and pressure. Considering the operating costs due to energy consumption and electrode erosion, the optimal conditions were found to be: 70 V/cm of electric field strength, 30 min of application time, and 588 kPa of pressure. The rate of electrodewatering doubled compared with that of mechanical dewatering (MDW) while the water content of the dewatered cake decreased by 25%. When an electric field is applied to the cake, clogging of the filter cloth becomes minimized due to electrophoretic mobility. The discharge of water from the cake porous matrix is facilitated owing to electroosmosis and the thermal effect due to joule heating. As a result, the dewatering capacity of electrodewatering improves compared with the mechanical dewatering. The energy consumption of electrodewatering was about 370-450 kWh/t (dry solid), which accounts for only one tenth of the existing sludge treatment costs.     

Generation of Active Oxidant Species by Pulsed Dielectric Barrier Discharge in Water-Air Mixtures

Experimental research into the electrical and optical parameters of pulsed dielectric barrier discharge (PDBD) was undertaken. PDBD was applied to humid air containing water droplets as a means of water oxidative treatment with short-living species generated in the discharge zone. In spectral analysis of PDBD, only small concentrations of nitric oxides were detected at the resulting electric field strength and electron mean energy sufficient for generation of OH-radicals. The water droplets served as electric field strength concentrators: PDBD was ignited close to the water droplets' surface.     

Formation of Nitrite- and Nitrate-Ions in Aqueous Solutions Treated with Pulsed Electric Discharges

The accumulation of nitrogen-containing ions formed in aqueous solutions dispersed in air and treated with pulsed corona, dielectric barrier and spark electric discharges, was studied dependent on electric conductivity and pH of treated solutions. The impact of conductivity to the spark and corona discharge is determined by the increased ohmic losses in the reactor. In contrast, the character of dielectric barrier discharge is significantly changed with growing conductivity resulted in increased nitrite-to-nitrate ratio. In alkaline solutions the production of nitrites is increased for the spark and the barrier discharge; the corona discharge produce only nitrates. The amount of nitrates produced in pulsed corona discharge at energy doses characteristic for potable water treatment is about 100 times lower than their maximum permissible concentration.     

Nitrate remediation in a novel upflow bio-electrochemical reactor (UBER) using palm shell activated carbon as cathode material

This study investigated the biological denitrification method which is a treatment method able to reduce inorganic nitrate compounds to harmless nitrogen gas. Autohydrogenotrophic denitrifying bacteria were used in this study to prevent any problematic outcomes associated with heterotrophic microorganisms. An upflow bio-electrochemical reactor (UBER) was used to accommodate hydrogenotrophic denitrifying bacteria employing palm shell granular activated carbon (GAC) as the biocarrier and cathode material. Bicarbonate as the external inorganic carbon source was fed to the reactor and hydrogen as the electron donor was generated in situ through electrolysis of water. Central composite design (CCD) and response surface methodology (RSM) were applied to investigate the effects of two operating parameters, namely electric current (I) and hydraulic retention time (HRT), on performance of the UBER. Electric current range of 0-20 mA and HRT range of 6-36 h were examined and results showed that nitrate can be entirely reduced within application of a wide operational range of electric current (10-16 mA) as well as HRT (13.5-30 h). However, increase of pH at cathode zone up to 10.5 inhibited nitrite reduction, and it was not reduced to the satisfactory level.     

Evaluation of geogrid as a reinforcement layer in clay based engineered barriers

Imperviousness of clay based barrier, which is provided in cover system of low-level radioactive waste disposal sites, is essential to mitigate the environmental hazard. The objective of this paper is to examine the influence of geogrid reinforcement on the deformation behaviour of clay based cover systems subjected to differential settlements. A series of centrifuge tests were performed on model clay barriers with and without the inclusion of geogrid reinforcement at 40 gravities. Motor-based differential settlement simulator was custom designed and developed for inducing continuous differential settlement in high gravity environment. By maintaining type and location of the geogrid within the clay barrier as constant, the thickness of clay barrier is varied. The performance of the clay barrier with and without geogrid layer having an overburden pressure equivalent to that of cover system was monitored by measuring water breakthrough at the onset of differential settlements. It was observed that both 0.6 m and 1.2 m thick clay barriers with and without overburden experienced cracks extending up to full depth. In comparison, geogrid reinforced clay barrier was found to sustain large distortions with an enhanced imperviousness. With the provision of an overburden equivalent to that of cover system, integrity of geogrid reinforced clay barrier was found to be retained even after inducing a distortion level of 0.125. This implies that provision of thickness of clay barrier equal to 0.6 m reinforced with a suitable geogrid may be adequate in sustaining higher distortion levels.     

Preliminary tests of an electrokinetic barrier to prevent heavy metal pollution of soils

Sardinia has to deal with significant environmental problems related to heavy-metal contamination, mainly located at its abandoned mining districts. In particular, acid mine drainage management and groundwater pollution are typical problems associated with mining activities which constitute a serious threat to human health. To prevent contaminant spread over the adjacent environment, it is of great interest to consider using an electric field as a containment fence to counteract pollutant transport. In this application, contaminant transport due to a hydraulic gradient driving force is prevented by the combined effect of electro-osmosis and electro-migration. Although there are other alternative containment technologies, the electrokinetic fence offers many advantages, as it is easy to operate, there is a minimal exposure to the operating personnel and it is likely to be effective for a wide range of contaminants. In this work, both one-dimensional (1D) and two-dimensional (2D) tests have been carried out. In the 1D tests, the efficiency of an electrokinetic barrier to prevent cadmium from polluting an uncontaminated sample was investigated; soil pH, metal concentration and current intensity have been monitored; results indicate that the barrier can prevent or significantly reduce heavy-metal contamination from spreading against a hydraulic gradient of 7. In 2D tests, two rows of electrodes inserted in a horizontally flat soil tank were used to generate an electric field. It was found that an electric field of 125 V m⁻¹ was sufficient to prevent significant copper incursion from a contaminant flow under a hydraulic gradient of 1.3.     

Control of Sludge-to-Wall Adhesion by Applying a Polarized Electric Field

An application of a polarized electric field to reduce adhesion of a biological sludge to the dryer wall was studied experimentally by contact drying of a sludge cake deposited on a heated metal plate serving as the cathode. It was found that the adhesion intensity is greatly reduced due to a water layer formed at the heated plate, when a fraction of water in the sludge migrates to the cathode by electro-osmosis, as well as by gas bubbles, which are generated by the electrochemical reaction. The voltage gradient from 4 to 5 V/cm was found optimal for drying 10-mm-thick sludge samples. Under these conditions, the electric energy consumption amounted to 3.87 kWh/t. An increase in cathode temperature reduced the sludge-adhering intensity and shortened drying time. The beneficial effect of an electric field on reducing sludge adherence decreases with increasing wall temperature.