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Totally found 25 items.

  • [资讯] Suppression of polymethyl methacrylate dust explosion by ultrafine water mist/additives
    The suppressions of ultrafine water mists containing additives (NaCl and NaHCO3) on 100 nm, 5 μm, and 30 μm polymethyl methacrylate (PMMA) dust explosions were experimentally studied in a dust-explosion apparatus. High-speed photography showed that maximum vertical positions and flame propagation velocities were significantly decreased by suppression with ultrafine water mist/additives. Flame propagation velocities in 100 nm, 5 μm, and 30 μm dust explosions suppressed by the ultrafine pure water mist were reduced by 48.2%, 27.7%, and 15.3%, respectively. Maximum temperatures and temperature rising rates measured by a fine thermocouple in nano- and micro-PMMA dust explosions were also significantly decreased. It was proved that the addition of NaCl and NaHCO3 improved the suppression effects of the ultrafine pure water mist. The improvement of explosion suppression by an 8% NaHCO3 mist was superior to that of a 16% NaCl mist. The suppression mechanisms of ultrafine water mist/additives are further discussed by analyzing the physical and chemical effects.
  • [资讯] Suppression of polymethyl methacrylate dust explosion by ultrafine water mist/additives
    The suppressions of ultrafine water mists containing additives (NaCl and NaHCO3) on 100 nm, 5 μm, and 30 μm polymethyl methacrylate (PMMA) dust explosions were experimentally studied in a dust-explosion apparatus. High-speed photography showed that maximum vertical positions and flame propagation velocities were significantly decreased by suppression with ultrafine water mist/additives. Flame propagation velocities in 100 nm, 5 μm, and 30 μm dust explosions suppressed by the ultrafine pure water mist were reduced by 48.2%, 27.7%, and 15.3%, respectively. Maximum temperatures and temperature rising rates measured by a fine thermocouple in nano- and micro-PMMA dust explosions were also significantly decreased. It was proved that the addition of NaCl and NaHCO3 improved the suppression effects of the ultrafine pure water mist. The improvement of explosion suppression by an 8% NaHCO3 mist was superior to that of a 16% NaCl mist. The suppression mechanisms of ultrafine water mist/additives are further discussed by analyzing the physical and chemical effects.
  • [资讯] Polymethyl Methacrylate (PMMA)
    Press release Polymethyl Methacrylate (PMMA) Darmstadt, October 17. 2016 KUNSTSTOFFE International, issue October 2016 Despite the tough market environment, the global sales market for polymethyl methacrylate is showing solid business growth and is leveling out demand fluctuations. Manufacturers are increasingly focusing on non-cyclical specialties in established application fields outside the fast-moving opto-electronics industry. The decision is intended to promote solid growth in the medium term...   Read more: KUNSTSTOFFE INTERNATIONAL, issue October 2016 . . .
  • [资讯] Experimental study on the accretion and release of ice in aviation jet fuel
    Ice formations in aircraft fuel systems pose a serious safety threat with potentially disastrous consequences, when restricting the fuel flow towards the engines. This is an ongoing challenge in the aerospace industry. In this work experimental studies have been performed to investigate the effects of temperature, flow rate and surface properties on the accretion and release of ice in flowing fuel. A test rig with a glass-windowed pipe has been employed to quantitatively measure the transient icing process under controlled conditions. The accreted ice exhibited soft and fluffy characteristics and was most likely the result of impinging solid ice particles that were entrained in the fuel flow. The ice particles were most sticky in a temperature range between −6 ◦C and −20 ◦C. The thickness of accreted ice decreased with roughness on aluminium surfaces and there was a significant reduction on polytetrafluoroethylene (PTFE) and polymethyl methacrylate (PMMA) in comparison to aluminium, copper or stainless steel surfaces. Comparison of the thickness of accreted ice with the ice adhesion strength reported in the literature showed a clear correlation. The experimental results will help to gain better understanding of the ice accretion process in flowing fuel and may serve as basis for design guidelines to minimize ice formation within an aircraft fuel system.
  • [资讯] Novel dual-functional coating with underwater self-healing and anti-protein-fouling properties by combining two kinds of microcapsules and a zwitterionic copolymer
    Antibiofouling and repairing of the micro-cracked coating on the surface of the facilities in underwater environment are two great challenges in marine industries. This paper prepared a dual-functional coating with underwater self-healing and anti-protein-fouling properties by combining two kinds of microcapsules and a zwitterionic copolymer. First, epoxy resin microcapsules and underwater epoxy hardener microcapsules were prepared. Epoxy resin microcapsules with a poly(urea-formaldehyde) shell and the entrapped mixture of epoxy resin and n-butyl glycidyl ether showed homogeneous spherical morphology with encapsulation ratio of 90.42%. Underwater epoxy hardener microcapsules with a polymethyl methacrylate shell and the entrapped underwater epoxy hardener showed cellular spherical morphology with encapsulation ratio of 78.67%. Both of the microcapsules exhibited pretty thermal stability and acid, alkali and salt resistance. Then, two types of microcapsules were mixed with amine cured epoxy coating system to cast film on steel piece, and subsequently a zwitterionic polymer, ploy(sulfobetaine methacrylate-co-glycidyl methacrylate)(PSG) solution was casted on the surface of the un-cured epoxy coating. Therefore, a dual-functional coating with underwater self-healing and antibiofouling functions was obtained. The self-healing anticorrosion function attributed to the dual microcapsules and the anti-protein-fouling performance provided by PSG layer had been certificated. The facile combination of underwater self-healing and anti-protein-fouling functions may provide a new protection strategy for marine and other underwater facilities.
  • [资讯] Performance evaluation and thermography of solid-propellant microthrusters with laser-based throttling
    Among propulsion devices, conventional solid-propellant thrusters require neither a tank nor a valve and therefore have relatively high reliability and simple structures. However, the interruption and restarting of thrust production in solid-propellant thrusters is difficult because combustion is autonomously sustained after ignition. Hence, we propose a new solid-propellant microthruster that can be throttled through laser heating. The proposed thruster uses a combustion-controllable hydroxyl-terminated poly butadiene/ammonium perchlorate-based solid propellant, wherein combustion is maintained only while the burning surface is heated using a semiconductor laser. In this study, thrust was measured at various laser-head traverse velocities to enhance the performance of the prototype. Moreover, propellant holders were fabricated from polycarbonate (PC) and polymethyl methacrylate (PMMA) because the melting point of PC is higher than that of PMMA, which could increase the local pressure in the interface between the propellant holder and the solid propellant and consequently reduce ignition delay. The prototype microthruster with the PMMA propellant holder yielded a thrust of 0.06 N and Isp efficiency of 70% at a laser power density of 0.83 W/mm2 and produced stable thrust at laser-head traverse velocities ranging from 0.85 to 0.95 mm/s, whereas that with the PC propellant holder exhibited unstable thrust in all tests. Firing tests showed an ignition delay of approximately 3 s and yielded a peak in Pc after ignition. Temperature profiles measured through thermography revealed that the burning-surface temperature was dependent on the laser-head traverse velocity and propellant-holder material. For stable combustion, the burning-surface temperature would be kept constant at 1040 K, an ignition temperature was 1250 K in vacuum, and one-half the ignition delay (1.5 s) is the time required for heating the burning surface to the ignition temperature.
  • [资讯] Indian Peroxide Limited Commissions 125 TPD Hydrogen Peroxide Manufacturing Plant In Gujarat
    Indian Peroxide Limited (IPL), one of India's major manufacturers and suppliers of specialty chemicals, has commissioned its new hydrogen peroxide plant complex in Gujarat, India. The state-of-the-art manufacturing facility produces industrial grade, premium quality and environment-friendly hydrogen peroxide () using Swedish technology provided by EB Nuberg that ensures highest quality standard production process to deliver premium quality hydrogen peroxide.
  • [资讯] 亚洲PMMA价格冲击六年新高
    中国石化新闻网讯 据安迅思新闻新加坡3月13日消息,受供应短缺的刺激,亚洲聚甲基丙烯酸甲酯(PMMA)价格已经攀升至六年来高点,突破3000美元/吨的大关,近期价格或仍将受到支撑。 安迅思数据显示,截止3月8日当周,亚洲PMMA价格上涨至平均3025美元/吨(CFR东南亚),比前一周上涨60美元/吨。 据安迅思数据显示,同期中国市场通用级PMMA价格上涨35美元/吨,上涨至3025美元/吨(CFR中国)。 张春晓 摘译自 安迅思新闻 原文如下: Asia PMMA hits 6-year high Asia's polymethyl methacrylate (PMMA) prices have climbed to a six-year high – above the $3,000/tonne mark – and may remain supported in the near term because of short supply. For the week ended 8 March, regional PMMA prices rose to an average of $3,025/tonne CFR (cost and freight) SE (southeast) Asia, up by $60/tonne from the previous week, ICIS data showed. PMMA prices in China for GP (general purpose)-grade goods increased by $35/tonne over the same period to $3,025/tonne CFR China, according to ICIS data.
  • [资讯] Evonik invests eight-figure sum in production plant for multi-layer PMMA films - Evonik Industries - Specialty Chemicals
    and intermediates, especially for use in agriculture and in the rubber and plastics industry. In 2015, the segment’s roughly 4,400 employees generated sales about €3.4 billion. About Acrylic Products The Acrylic Products Business Line of Evonik’s Performance Materials Segment manufactures the inspiring brand plastic PLEXIGLAS® and offers a wide range of specialty semi-finished products for a variety of future-oriented applications. Major markets for PLEXIGLAS® are the aviation industries, architecture and the construction industry, lighting and design applications, electronics and communication, furniture and exhibition booth construction as well as store fixtures. With production facilities in Europe, North America, South Africa and Russia and a global sales network, AP is one of the leading producers of polymethyl methacrylate (PMMA) worldwide. In 2015, the business line’s roughly 1,000 employees generated sales of 375 million €. Evonik’s PMMA products are sold under the PLEXIGLAS® trademark on the European, Asian, African and Australian continents and under the ACRYLITE® trademark in the Americas. Disclaimer In so far as forecasts or expectations are expressed in this press release or where our statements concern the future, these forecasts, expectations or statements may involve known or unknown risks and uncertainties. Actual results or developments may vary, depending on changes in the operating environment. Neither Evonik Industries AG nor its group companies assume an obligation to update the forecasts, expectations or statements contained in this release.
  • [资讯] 欧洲甲基丙烯酸甲酯市场企稳
    中国石化新闻网讯 据ICIS网站10月19日消息 由于供应中断和健康的需求,欧洲甲基丙烯酸甲酯(MMA)市场保持稳定。     需求强于预期,涂料和汽车行业表现仍好于预期。     亚洲和美国市场依然坚挺,两个地区都出现了强劲的供需问题。因此,对欧洲的进口仍然有限。     10月和第四季度合同的谈判正在进行中。     受健康需求和有限进口的推动,生产商分别将10月份合同谈判的目标定为两位数的涨幅。尽管目前市场状况良好,但预计在维修关闭季节结束后,这一状况将略有缓解。     第四季度的合约也瞄准了上涨,上涨幅度取决于起始点。     9月份的合同价格上个月以两位数的涨幅结算。     几乎所有的甲基丙烯酸甲酯都用于制备均聚物和共聚物,最大的应用是聚甲基丙烯酸甲酯(PMMA)或改性聚合物的浇铸、模塑或挤出。     王磊 摘译自 ICIS     原文如下:     Europe MMA market remains snug amid shutdown season     The European methyl methacrylate (MMA) market remains snug due to supply disruptions and healthy demand.     Demand is stronger than expected, with the coatings and automotive sectors still performing better than expected.     The Asian and US markets remain firm, with strong demand and supply issues seen in both regions. As a result, imports into Europe remain limited.     Negotiations for October and fourth-quarter contracts are ongoing.     Producers are separately targeting double-digit increases for October contract discussions, driven by healthy demand and limited imports. Although the market is currently snug, this is expected to ease slightly after the maintenance shutdown season is over.     Fourth-quarter contracts also are targeting increases, with the extent of any rise depending on starting point.     September contract prices settled last month at a double-digit increase.     Nearly all MMA is polymerised to make homopolymers and copolymers, the largest application being the casting, moulding or extrusion of polymethyl methacrylate (PMMA) or modified polymers.
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