橡胶热老化的几种测试方法

介绍了几种评估橡胶耐热老化性能的方法以及用于表征橡胶耐热老化性能的表达式。     

硫化橡胶老化定量分析法

橡胶老化长久以来定性容易,定量难。文中详细论述了导致橡胶老化的几大因素,重点介绍了老化定量分析的几种方法(FT-IR、DSC、GPC、TG、ESR、NMR、XPS),从而能够比较准确地推断橡胶制品的使用寿命。     

二段硫化对聚丙烯酸酯橡胶结构与性能的影响

用Ｘ射线能量分散谱仪研究了活性氯型聚丙烯酸酯橡胶（ＡＣＭ）在二段硫化过程中氯元素和硫元素质量分数的变化及二段硫化条件对ＡＣＭ的物理性能、耐热老化性、耐热油老化性、压缩永久变形性的影响。结果表明：二段硫化过程中，橡胶中氯质量分数不断减小，硫质量分数先升后降，交联键中的多硫键转变为双硫键、单硫键或碳碳键，交联结构趋于稳定；二段硫化可改善体系的耐热性、耐热油性及耐压缩永久变形性。     

热空气老化对芳纶/橡胶复合体系粘合性的影响研究

研究了热空气老化对芳纶／橡胶复合体系粘合性的影响，通过对H抽出力一位移曲线特征值分析考察，发现芳纶经一定条件的空气等离子体处理再结合浸胶处理，与橡胶形成的粘合体系有较好的耐热空气老化能力和抵抗粘合破坏的能力，综合性能良好。     

氯醚橡胶/丁腈橡胶橡胶共混物性能的研究

研究了共聚型氯醚橡胶／丁腈橡胶共混比、促进剂ＮＡ－２２用量、补强剂及软化剂对共混物性能的影响。结果表明：随着氯醚橡胶用量的增加，共混物的耐低温性、耐热氧老化性、耐油性及耐ＣＣｌ＿４和ＣＨＣｌ＿３性能提高，但拉伸强度降低；当促进剂ＮＡ－２２和半补强炭黑的用量分别为１．５和６０份时，氯醚橡胶／丁腈橡胶（６０／４０）共混物的拉伸强度及撕裂强度出现峰值；使用液体丁腈橡胶作软化剂．使共混物的耐低温性、回弹值、撕裂强度、扯断伸长率及耐油性提高，但耐热氧老化性及耐ＣＣｌ＿４和ＣＨＣｌ＿３性能降低。     

粘土/橡胶纳米复合材料老化性能研究

研究粘土 /SBR及粘土 /NR纳米复合材料的耐热氧老化和耐臭氧老化性能 ,并考察粘土 /SBR纳米复合材料的热失重和气体阻隔性。结果表明 ,粘土 /SBR纳米复合材料的耐热氧老化和耐臭氧老化性能均优于炭黑 /SBR复合材料 ;粘土 /NR纳米复合材料的耐热氧老化性能略优于炭黑 /NR复合材料 ,耐臭氧老化性能与炭黑 /NR复合材料相差不大 ;均匀分散的纳米粘土可提高橡胶的热稳定性和气体阻隔性 ,减缓氧及臭氧在橡胶中的扩散 ,降低橡胶分子链受攻击的几率 ,有利于提高橡胶耐热氧老化和耐臭氧老化性能     

填料对天然橡胶/溴化丁基橡胶高阻尼橡胶性能稳定性的影响

研究填料对天然橡胶/溴化丁基橡胶高阻尼橡胶物理性能及阻尼性能稳定性的影响。结果表明:填料用量一定时,仅用炭黑N330填充的高阻尼橡胶物理性能最优,但耐热氧老化性能最差;采用云母粉替代部分炭黑N330制备的高阻尼橡胶物理性能略有下降,热氧老化后物理性能和阻尼性能变化率最小,耐热氧老化性能最佳;木质素替代部分炭黑N330填充的高阻尼橡胶耐热氧老化性能介于两者之间。     

纳米补强剂对MVQ/AEM共混胶性能的影响

采用机械共混方法,在乙烯丙烯酸酯橡胶中加入甲基乙烯基硅橡胶共混,研究了纳米白炭黑和纳米炭黑品种及两者并用对MVQ/AEM共混胶的硫化特性、物理机械性能、耐热老化性能、耐油性能、高温压缩永久变形性及动态力学性能的影响。结果表明,当采用纳米沉淀法白炭黑和纳米气相法白炭黑并用补强体系时,共混胶具有较好的物理机械性能和耐热老化性能。     

炭黑对橡胶耐热老化性能的影响

研究炭黑对橡胶耐热老化性能的影响。结果表明:在炭黑结构相同的条件下,随着炭黑粒径增大,胶料的门尼粘度减小,强伸性能降低,耐热老化性能提高;通过并用耐热老化性能好的炭黑可以改善胶料的耐热老化性能。     

金属(氢)氧化物对氟醚橡胶耐热老化性能的影响

考察了金属（氢）氧化物对氟醚橡胶耐热老化性能的影响,并从理论上进行了探讨。热重分析结果表明,在氟醚橡胶的热老化过程中没有明显的氧化裂解发生,但氧对其热老化有一定的促进作用;金属（氢）氧化物可以促进氟醚橡胶的硫化,并可使其生成热稳定性更高的交联结构,有利于提高氟醚橡胶的耐热老化性能,特别是长时间耐热老化性能     

水泥水化热测定方法综述

水泥水化热是中、低热水泥和核电工程用水泥的一项关键的技术指标。全球范围内测定水泥水化热的方法有溶解法、直接法/半绝热法、等温传导量热法三种。本文总结了中、美、欧相关方法标准,对其测试原理、仪器设备、试验过程等方面进行了比对,并对其在领域的应用做了简单的概括。     

乙烯酮(双乙烯酮)下游产品废水的治理技术

乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。     

气化给煤系统故障分析

气化给煤装置自投运以来,出现了气化煤仓堵煤、称重给煤机输送皮带因跑偏而损伤以及清扫装置故障频繁等问题,多次造成气化系统减负荷运行。通过对出现的各种问题进行分析,找到了产生这些问题的原因,并有针对性地采用配煤和改进清扫链等措施,使出现的问题得到了极大的改善。     

Stability of granules of solid solutions of poly-pehnyleneterephthalamide

Conclusions Studies of starting solutions of PPTA in sulfuric acid and of granules obtained under pressrue at low temperature, and of granules stored in a hermetic package, have been carried out by the methods of differential thermal analysis, turbidity spectrum and viscometry.On granulation of a solidified PPTA solution, short-term storage of the granules in a hermetic package, or short contanct of the granulated mass with air, no appreciable change in melting point or of the intrinsic viscosity of the system takes place.Long storage of a granulated solution, even in hermetic packages, can lead to a considerable decrease in the melting point of the crystal solvates, caused by an increase in defectiveness of crystal structure under the effect of moisture.Translated from Khimicheskie Volokna, No. 3, pp. 25–26, May–June, 1986.     

Analysis of products of high-temperature pyrolysis of various hydrocarbons

Ethane, ethylene, acetylene, propane and neopentane have been pyrolyzed at 1173 K, and methane at 1372 K in a flow system, and the volatile pyrolysis products analyzed. Eleven aromatic hydrocarbons, containing 14 or fewer carbon atoms, accounted for 98 + % of the liquid products recovered in each case. Benzene was the main product, followed by naphthalene. No compounds with branched chains or multiple substituents were present, and compounds containing even numbers of carbons comprised 93–99% of each mixture. Acetylene was a major component of the gaseous effluent from each of the initial hydrocarbons. The effect of temperature on the composition of the gaseous effluent during pyrolysis of methane, ethane and ethylene was determined. Carbon film deposition from methane commenced at about 1273 K; from ethane at 1015 K and from ethylene at 1100 K, in each instance coinciding with the appearance of acetylene in the effluent. As the temperature was raised, at first the increase in the rate of carbon deposition closely followed the increase in the concentration of acetylene in the effluent. It is proposed that acetylene may be a common factor in the pyrolysis of aliphatic hydrocarbons, perhaps acting as the precursor of both surface carbon and aromatic hydrocarbons by a process of head-to-tail linkage of two-carbon units at active surface sites to form chains that then undergo dehydrogenation to carbon or cyclization and desorption as aromatic species.     

142例新生儿溶血病血清学检测结果分析

目的对本地区142名新生儿溶血病患者进行血清学检测,评价直接抗人球蛋白试验、游离抗体试验和抗体释放试验在该病诊断中的价值。方法对2005年1月~2007年6月各医院送检的高胆红素血症新生儿血液标本进行"三项试验"。结果142名新生儿溶血病患者中,血型分布规律为:B>A>AB>O,54.22%为B型,43.66%为A型,二者差异有显著意义。直抗试验阳性率为76.76%,释放试验阳性率为100%,游离试验阳性率为50.70%。释放试验阳性的A型患者中,抗-AB检出率为47.17%,B型患者中的检出率为53.03%,二者差异无显著意义。结论释放试验敏感度最高,是判定新生儿溶血病最有力的证据,在本地区,B型新生儿可能更易患新生儿溶血病。     

Effect of degree of deacetylation of chitosan on the kinetics of ultrasonic degradation of chitosan

The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003     

Model of Cellular Instability of Flames of Ternary Mixtures

A simple phenomenological diffusive-thermal model of cellular instability of premixed flames of ternary mixtures is developed and presented. The model shows that preferential diffusion can alter stoichiometry of the mixture, i.e., the ratio of the fuel and oxidizer concentrations, and also its effective dilution by an inert. Key parameters of the model are estimated using numerical modeling of burning velocities. Laminar burning velocities are calculated for hydrogen-oxygen-nitrogen, methane-oxygen-nitrogen, and propane-oxygen-nitrogen mixtures. Conditions for the appearance of cellular instability in ternary mixtures are determined and compared with experiments. In good agreement with experimental observations, the diffusive-thermal instability is predicted in hydrogen flames with equivalence ratios φ ≲ 1.45, in lean methane flames with φ ≲ 1.02, and in rich propane flames with φ ≳ 1.03. The magnitude of the change in the local flame velocity due to preferential diffusion is evaluated. It is demonstrated that nitrogen diffuses faster than oxygen in hydrogen-air and methane-air flames, while oxygen diffuses faster than nitrogen in flames of propane and other heavier hydrocarbons. In mixtures of air with propane or heavier hydrocarbons, the transition between stable and unstable regimes is predicted in mixtures that are leaner than the mixture corresponding to the peak of the burning velocity curve, in agreement with experimental observations. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 5, pp. 14–22, September–October, 2005.     

化学化工数据局外点检测方法研究进展

局外点检测对于注重试验和数据采集的化学化工领域,其重要性不可忽视。结合化学化工的数据特点,对局外点检测方法的理论基础、应用需求、研究思路、技术关键和发展进程进行了综合分析。分别针对线性和非线性参变对象,概要介绍了当前适用的检测方法,包括各类判别标准、直接和间接方式、单个和多个局外点检测、经典和现代方法以及它们的优缺点和最新进展。最后展望了局外点检测方法的前景和发展方向。     

浅谈安全中的“以人为本”

在安全生产系统中,人的素质是占主导地位的,人的行为贯穿生产过程的每一个环节。企业安全要以人为核心,树立人本观念。安全管理必须重视人的因素,提高人的素质,从精神上、物质上关心人尊重人,以有效的手段约束和激励人,加大安全投入、落实有效措施,保障个人的利益,使大家找到归属感,保护员工身体健康和生命安全,最终形成安全管理＂命运共同体＂,推动企业发展和提高。