乙丙橡胶产品结构将发生变化

乙丙橡胶是仅次于丁苯橡胶(SBR)和顺丁橡胶(BR)的第三大合成橡胶,在世界合成橡胶生产中占到12％左右。根据世界合成橡胶生产者协会(ILSRP)2002年统计,2002年世界乙丙橡胶的总生产能力为111.8万吨／年,2002年世界乙丙橡胶总消费量为85.4万吨／年,2002年中国的消费量为2.9万吨／年。     

2002年天津渤海化工生产情况简述

2002年是我国加入WTO的起步之年,天津渤海化工集团公司的广大职工在国家经济发展、政治稳定的大环境下抢抓机遇,真抓实干,化工生产保持了两位数增长,创集团公司化工生产的历史最好水平。1 2002年化工生产情况1.1 工业总产值 2002年集团公司的化工生产继续保持了上一     

工程新闻

·谭竹洲提出2003年十项重点任务 中国石油和化学工业协会在京召开了2002年度总结大会。协会会长谭竹洲发言指出,2002年,在各专业协会和会员单位的积极努力下,石油和化工协会的发展已逐步走上正轨,各项业务全面展开,自身建设迈出了新的步伐。 党的十六大提出走新型工业化道路,为协会工作明确了思路、指明了方向。协会2002年在经济运行、统计分     

TDK进军DVD-R/-RW光驱市场

TDK在2002年3月13日～20日于德国汉诺威举办的“CeBIT 2002”上宣布将进军DVD-R/-Rw光驱市场,并展示了刻录播放装置。估计相关产品将在2002年6月投放欧洲市     

巴斯夫环境、健康与安全目标进展顺利

与2002年基准相比,巴斯夫2012年每吨销售产品温室气体排放减少了31.7%,能源效率提高19.3%。同期工伤事故数量减少48%。环境、健康与安全目标实现进度见巴斯夫全球2012综合年报。巴斯夫设定了全球2020年目标,公司希望在2002年基础上将     

部分国家和地区水泥工业情况报告（下）

(接上期)中国台湾 经济形势 受全球经济逐步复苏的影响,世界贸易和商务活动越来越活跃。2002年第一季度台湾的经济增长为0.89％,显然比2001年第四季度的-1.87％有所改善。 水泥工业 自从2001年6月份,台湾水泥协会的Ho-Ping Plant第二条生产线开始生产以来,2001年熟料产量为2823万t,2002年的产量保持在这个水平。 1.水泥产量 2002年上半年熟料产量为901万t,比2001年同期增长l％。 2002年上半年水泥生产产量为957万t,比2001年同期增长5.5％。 预计2002年水泥产量为1980万t。     

世界合成纤维各品种生产能力

<正> 据Fiber Organon June 2002,2003报道,2003年世界合成纤维生产能力又出现了较大幅度的增长,比2002年增长9.88％达到36273 kt/a。涤纶仍然是增长最快的品种,比2002年增长13.89％达到27521 kt/a。腈纶在2002年减少1.94％的基础上增长1.25％达到3258 kt/a。锦纶在2002年减少2.12％的基础上继续减少2.58％为5039 kt/a。从地区看,增长的主要地区     

行业动态

总结成绩 表彰先进 湘瓷科艺召开2002年度 总结表彰大会 本刊讯 元月27日上午,湘瓷科艺召开了简朴而又隆重的2002年度总结表彰大会。该公司董事长胡良页先生在会上发表了热情洋溢的讲话,就2002年公司在提高产品质量、拓展营销     

世界羰基化学品生产与市场

OXO化学品的下游市场的需求受全球经济状况的影响,结果是对OXO化学品的需求紧紧跟随世界经济的主流,其主要的用途包括建筑/改造、汽车生产和原始设备生产(OEM)。2002到2007年期间,预计全球OXO化学品生产能力年均增长率将从1998年到2001年期间的4.7%下降到1.7%。1998年到2002年期间,OXO化学品生产能力大约增加了1.8Mt,主要是在东南亚地区。尽管2002年到2007年期间新增OXO产能的数量和步调急剧下降,但预计全球市场仍然供大于求。     

我国石油和化工行业经济运行回顾与展望

回顾了2001年和2002年第一季度我国石油和化工经济运行情况,对2002年4月初出现转折的成因及上市公司进行了分析,展望了2002年后3个季度的运行趋势.     

Anionic polymerisation of methyl methacrylate with complex initiator system

Summary Polymerisation of methyl methacrylate was conducted by using alkyl lithium/dimethylsulfoxide (DMSO) system as initiator in toluene. A special attention was focused on using some lithium polyetheralkoxides as polymerisation promoters at ambient temperatures. Poly(methyl methacrylate) samples were characterized with Gel Permeation Chromatography (GPC), Nuclear Magnetic Resonance Spectroscopy (¹H NMR) and Differential Scanning Calorimetry (DSC). The positive effect of the μ/σ type ligands such as lithium 2-(2-methoxyethoxy)ethoxide (LiOEEM), 2-(methoxy)ethoxide (LiOEM) on controlling the living character, molecular weight, stereo regularity and the yield of the produced polymers was demonstrated. It has been found that this approach provided high polymerisation yields and low polydispersity but low initiator efficiency. Received: 9 April 2002 / Revised version: 10 May 2002 / Accepted: 15 June 2002     

A new photoresist based on hyperbranched poly(ary1ene ether phosphine oxide)

Summary Hydroxy-terminated hyperbranched poly(ary1ene ether phosphine oxide) (P2) was synthesized via nucleophilic aromatic substitution reaction of AB, monomer, bis(4-hydroxyphenyl)-4'-fluorophenylphosphine oxide with K₂CO₃ as a base in NMP. The obtained polymer was dissolved well in NMP and DMSO, and casting of the solution gave a transparent film. The study on dissolution behavior of the film containing 10 wt% of diphenyliodonium-9,l0-dimethoxyanthracene-2-sulfonate (DIAS) as a photoacid generator and 25 wt% of 4,4'-methylenebis-[2,6-bis(hydroxymethylphenyl) phenol] (MBHP) as a cross linker revealed that 0.5 wt% aqueous tetramthylammonium hydroxide (TMAH) solution was a suitable developer for this negative-type photoresist system. The photoresist system containing 10 wt% of DIAS and 25 wt% of MBHP showed the sensitivity of 9 mJ/cm² and the contrast of 1.6 when it was exposed to 365 nm light and postbaked at 12O°C, followed by developing with 0.5 wt% aqueous TMAH solution at room temperature. The heat-treated (300°C, 30 min) negative image did not show any distortion. Received: 7 October 2002/Revised version: 10 December 2002/ Accepted: 11 December 2002 Correspondence to Sang youl Kim     

An empirical model and scenario analysis of nitrous oxide emissions from a fertilised and grazed grassland site in Ireland

This paper describes an empirical model of soil-evolved nitrous oxide emissions inferred from data gathered in a 2-year rotational grazing experiment investigating emissions from a fertilised and grazed grassland site. The model was used to simulate daily and annual emissions for the 9-year period between 1994 and 2002 under different possible fertiliser application scenarios. As the model only requires a small number of commonly available site-specific data inputs, this facilitates its use at different geographical locations. This is the first empirical modelling of daily fluxes to give estimates of annual emissions. Results reveal a high interannual variability of emissions that increases with the amount of nitrogen fertiliser applied. Simulation using the model for the period 1994–2002 indicated that higher soil moisture status on the day of fertiliser N application increased the average annual nitrous oxide emissions.     

Bulk functional oligomerization of ɛ-caprolactone in a mini extruder

Summary ɛ-caprolactone has been polymerized in bulk in a mini-extruder with Al(OiPr)₃ as initiator and benzyl alcohol as transfer agent. Polymer chains have been characterized by ¹H NMR, SEC and Maldi-Tof mass spectroscopy in order to investigate the potentialities of this process in terms of macromolecular engineering. Low temperatures around 75°C are enough to perform oligomerization at high conversion with a mean residence time less than 2 minutes. All the polymer chains are actually functionalized by the chemical group issued from the transfer agent. Molecular weight distribution depends on the temperature as well as on the residence time. Received: 3 October 2001/Revised version: 18 February 2002/ Accepted: 7 M?rz 2002     

Control of the photorefractive effect using a low Tg sol-gel glass

Summary We prepared the photorefractive sol-gel glass based on organic-inorganic hybrid materials containing a charge transporting molecule, second-order nonlinear optical chromophore, photosensitizer, and plasticizer. Carbazole and 2-{ 4-[(2-hydroxyethyl) methylamino]benzylidene}malononitrile were reacted with 3-isocyanatopropyl triethoxysilane and the functionalized silanes were employed to fabricate the efficient photorefractive media including 2,4,7-trinitrofluorenone (TNF) to form a charge transfer complex. The simplest way to vary the composition in the matrix was to mix the desired amount of the functionalized alkoxysilane. The prepared sol-gel glass samples contained a large amount of nonlinear optical (NLO) chromophore compared to that of the charge transporting molecules. They showed a large net gain coefficient and high diffraction efficiency at certain conditions. Received:27 May 2002/Revised version:23 August 2002/Accepted:7 September 2002 Correspondence to Dong Hoon Choi E-mail: dhchoi@khu.ac.kr     

Synthesis and characterization of poly(ethylene terephthalate‐co‐isophthalate)s with low content of isophthalate units

The objective of this work was to study the effect of the introduction of low amounts of isophthalate units on the mechanical properties, crystallization rates, and thermal parameters of poly(ethylene terephthalate). For this reason a series of five random poly(ethylene terephthalate‐co‐isophthalate) copolymers, containing 0.5, 1, 1.5, 2, and 4 mol % isophthalic acid, were prepared by the melt polycondensation process. The intrinsic viscosity of copolymers ranged between 0.7 and 0.8 dL/g. The increase of isophthalate content resulted in a significant decrease of the crystallization rates, but in a small decline of tensile strength, Young's modulus, and elongation at break, whereas tensile strength at yield point remained almost unaffected. Also, a decrease in the melting point was recorded, whereas the glass‐transition temperature was only very slightly affected. The higher decrease for the aforementioned parameters was noted for the copolymer with 4 mol % isophthalate units content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1931–1941, 2002     

High‐pressure phase equilibria for a styrene/CO2/polystyrene ternary system

To reveal the possibility of supercritical (SC)‐CO₂‐assisted devolatilization of polystyrene, the equilibrium composition data for the CO₂ phase in a styrene/CO₂/polystyrene ternary system is determined by a semistatic experimental technique. The parameters in the lattice–fluid equation of state of Sanchez and Lacombe are determined for the investigated system. The distribution coefficients of styrene between the polymer and the supercritical fluid phases are investigated experimentally at 318 and 328 K over the pressure range of 12–20 MPa. The binary interaction parameter between styrene and CO₂ is obtained by regression of the vapor–liquid equilibrium data. The interaction parameter between CO₂ and polystyrene is calculated by using the sorption data from the literature, and the interaction parameter between styrene and polystyrene is optimized by using the measured data of this study. The investigation of the distribution coefficients indicates that styrene can be removed from polystyrene by SC‐CO₂ at near room temperature and moderately high pressures. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1938–1944, 2002     

A novel hyperbranched polyester functionalized with azo chromophore: synthesis and photoresponsive properties

Summary A hyperbranched polymer containing azo chromophores on the periphery has been synthesized from transesterification reaction between a hyperbranched polyester bearing peripheral hydroxyl groups and ethyl 4-{4'-[N, Ndi(hydroxyethyl)aminobutoxy]phenylazo}benzoate. The hyperbranched polyester was obtained by adding the AB₂ monomers step by step to a multifunctional core molecule. Narrow molecular weight distribution, with a polydispersity index as low as 1.1, was achieved by this method. The azobenzene- functionalized hyperbranched polymer as well as the corresponding azo monomer showed typical photoresponsive behavior of an azobenzene type molecule. The trans azobenzene units of the hyperbranched polymer could be reversibly switched by UV irradiation to the cis form that recovered slowly to the trans form in the dark. However, significantly less conversion from the trans isomer to the cis isomer was observed for the azobenzenefunctionalized hyperbranched polymer at the photostationary states under the irradiation of UV light, which could be attributed to the increased steric hindrance in the hyperbranched polymer. Received: 1 April 2002 /Revised version: 10 July 2002/ Accepted: 15 July 2002     

Mechanical properties of soft liner–poly(methyl methacrylate)‐based denture material

In this study, the mechanical properties of two different permanent soft lining materials and their bonding to poly(methyl methacrylate) (PMMA) were compared. Both of the soft liners were heat‐cured commercial materials. The polymerization was carried out by conventional methods suggested by manufacturer, and the curing was done at the temperature of boiling water for 5, 15, 25, and 35 min. The sample groups were tested in the computer‐aided tensile‐testing machine at a rate of 2 mm/min. The slow rate helps the collection of more and more reliable data. At this time, the stress–strain curves were used to calculate ultimate tensile strength, elastic modulus, resilience, and toughness. The measurements were carried for PMMA, Molloplast B, Flexor, and a combination of PMMA/soft liner. After introducing the soft lining material on PMMA of the same thickness, the new material structure was more elastic than the original PMMA. Flexor showed adhesive failure at studied curing periods, but Molloplast B gave larger tear strength values and cohesive rather than adhesive failure at the 25‐min and 35‐min curing times. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 467–474, 2002     

Condition monitoring of a thermally aged elastomer by 1H‐NMR T2 relaxation measurements of solvent‐swelled samples

The aging of polymers is often monitored by mechanical property measurements such as those of Young's modulus or tensile elongation at break; new methods are required, however, in situations where traditional mechanical methods cannot be employed. A hydroxy‐terminated polybutadiene/isophorone diisocyanate elastomer is commonly used as a propellant binder. The thermal degradation of the binder is believed to be an important parameter governing the performance of the propellant. Classical mechanical methods cannot be used to monitor the condition of this material when it has been aged in situ as a highly dispersed binder. In this study, the ¹H‐NMR spin‐spin relaxation times, T₂, of solvent‐swelled samples decreased substantially as thermally induced oxidation led to additional crosslinking. A time–temperature superposition analysis of the relaxation times was performed on samples that had been aged at temperatures ranging from 50 to 125°C. The acceleration factors derived from the relaxation measurements agreed with those reported earlier for tensile elongation at break and oxygen consumption. The dependence of T₂ on tensile elongation at break was independent of the temperature at which the sample was aged. A shortened version of the experiment, requiring only two spin‐echo delay times, is presented. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3636–3641, 2002