聚碳硅烷的高温高压生成机理研究II蒸馏产物的结构分析

以液态聚硅烷(LPS)在450℃反应得到的聚碳硅烷(PCS)粗产品为原料,经溶解、过滤、热处理后减压蒸馏,收集蒸馏馏分并进行表征,由此推出不同摩尔质量的PCS的典型结构,进而推测出LPS转化为PCS分子的机理是:随着温度的升高,LPS中的Si—Si键发生断裂、重排,转化为Si—C键,生成低分子碳硅烷;随着温度的继续升高,碳硅烷分子间发生脱氢、脱甲烷缩合反应,摩尔质量逐渐长大,生成PCS。     

Annealing of polyacene‐based oligomer synthesized under high pressure

A polyacene‐based oligomer was synthesized by reaction of diphenyldiacetylene under high pressure (pressure: 0.1 GPa; temperature: 250°C; time: 5 h). Annealing of the polyacene‐based oligomer was carried out (temperature: 300–800°C; time: 5 h). Gas analysis, BET surface area measurement, Raman scattering, X‐ray diffraction, elemental analysis, ¹³C‐NMR, and conductivity measurements were performed to characterize the structure of the product. The oligomer was annealed with the appearance of mainly hydrogen. The H/C of the product decreased with increasing annealing temperature. The Raman band is observed at 1610 cm⁻¹ assigned to a doubly degenerate deformation vibration of the carbon hexagonal ring. The additional band observed at 1340 cm⁻¹ is attributed to the size effect. X‐ray diffraction indicated that the product had no sharp peak because of the disordered carbon structure. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 289–292, 1999     

高熔体强度聚丙烯树脂的结构与性能

采用差示扫描量热法、傅里叶变换红外光谱、毛细管流变、熔体拉伸等方法,从结晶性、黏弹性及物理机械性能等方面对高熔体强度聚丙烯(HMSPP)树脂进行结构表征与性能分析。结果表明:HMSPP树脂具备较高的弯曲模量,同时具备优异的抗熔垂能力和更宽的加工温度;拉伸黏度随拉伸速率的增大而增大,呈现出HMSPP应变硬化这一明显行为,使得熔体在热成型过程中具有均匀变形的自我调节能力,从而克服普通聚丙烯在热成型加工中的严重熔垂问题;含有较长接枝链段的HMSPP树脂在刚性、熔体强度、结晶性能等方面均优于普通聚丙烯。     

超高分子质量聚碳硅烷的合成与表征

从常压合成得到的中低分子量PCS出发进行热压合成制备超高分子质量的PCS,并对其结构和性能进行了表征。研究表明控制热压反应温度在460~470℃、预加压力1~2 MPa、反应6h时得到先驱体PCS的Mw为6 400~8 500;热压合成后制得的超高分子质量PCS的Si—H含量和支化度有所降低;通过控制热压反应时间可以较好的调控超高分子PCS的重均分子质量的大小。     

常压等离子体处理芳砜纶的结构与性能研究

分别采用氦气和氦气/氧气对芳砜纶进行常压等离子体处理。采用滴水吸收实验测定处理前后纤维表面的润湿性,利用扫描电子显微镜和X射线光电子能谱仪分析处理前后纤维表面形态和化学成分的变化。结果表明:经常压等离子体处理后芳砜纶表面粗糙度增加,纤维表面碳元素含量下降,羟基、羧基等含氧或氮的极性基团增加,芳砜纶纱线的润湿性能提高,纱线强度没有明显变化,氦气/氧气等离子体处理比氦气等离子体处理效果更好。     

高温高压下的绝缘胶接体系研究

叙述了在温度155~175℃,14 MPa压力下使用的绝缘胶接体系研究情况,实物电子线圈8中线与线间绝缘电阻值、线与屏蔽层间绝缘电阻值都大于10Ω,该体系已应用在石油测井仪。     

高刚性高耐热聚丙烯的结构与性能

采用核磁共振碳谱、差示扫描量热法、凝胶渗透色谱等研究了高刚性、高耐热聚丙烯专用树脂K1708、K1712的链结构和聚集态结构。结果表明．K1708、K1712分子链规整度好、相对分子质量分布较宽,与同类进口产品的结构与性能相近。     

高温高压锅炉在干熄焦工程中的应用

结合以往对各种干熄焦锅炉的标定数据以及在干熄焦锅炉选择过程中存在的制约因素,对干熄焦装置的生产能力、工程投资及企业现状等因素进行对比分析,为干熄焦锅炉炉型的选择提供了建议。同时针对高温高压自然循环干熄焦热力系统和中温中压联合循环干熄焦热力系统,在节能方面、锅炉效率、钢材消耗、系统电力消耗、发电量的差异以及锅炉的开工与运行方面的差异进行了对比分析,进而了解两种参数的热力系统在各方面的优缺点。     

Viscosity variations of coal-oil slurry under high temperature and high pressure during heating process

Heating coal-oil slurry (COSL) is an important step in direct coal liquefaction. Some physical and chemical properties of COSL including its viscosity will change during heating. A rotary viscometer was self-designed to measure the viscosity of COSL under high pressure and temperature. Three kinds of coal, which are Yanzhou coal (middle rank and caking), Shenhua coal (low rank and non-caking) and Shengli coal (brown coal), were mixed with anthracene oil to prepare the COSL. The COSL from Yanzhou, Shenhua and Shengli at the same experimental conditions showed different viscosity variations under high hydrogen pressure during heating. Yanzhou COSL had a higher viscosity peak, while Shenhua COSL had two small viscosity peaks and in the case of Shengli COSL, no viscosity peak was present under a high hydrogen pressure during the whole heating process. The coal nature is the important factor of viscosity variations of COSL. The higher the coal rank, the more caking coal is present, and the more obvious the viscosity variations of the COSL are.     

Laser ablation behavior of flake graphite and SiO2 particle-filled hyperbranched polycarbosilane matrix composite coatings

Composite coatings consisting of flake graphite and SiO₂ fillers in a hyperbranched polycarbosilane (HBPCS) matrix were designed and prepared to meet the requirements of laser protection. The laser ablation behavior of the composite coatings were investigated. Control experiments were designed to study the performance of SiO₂ during laser irradiation. The results show that the introduction of SiO₂ changes the anti-laser protective mechanism and can improve the anti-laser property of the coating. High power laser irradiation results in pyrolysis of HBPCS and the formation of SiC particles. Chemical reactions between SiO₂, graphite, and SiC play an important role in consuming energy, and provide an excellent cooling effect to the substrate, leading to decreased temperature. SiC particles formed on the surface of the laser ablation area act as a shield to prevent the laser from irradiating deeper layers of the coating. Due to the cooling effect and thermal stability of SiC, the proposed coating shows a good anti-laser property.     

高压常温制液氯工艺研究

讨论了高压常温法制备液氯的工艺，介绍了液化温度、原料氯气纯度等对工艺的影响及对液化温度、氯压机输出压力的控制方法。通过对比，认为一级压缩与二级压缩在能耗上无大的差别，高压常温法氯气液化工艺安全性较高。     

高压喷射泵故障的判断和影响

介绍赤天化股份公司二氧化碳汽提尿素装置高压喷射泵工作异常,高压系统压力偏高、循环系统放空较大等情况,对异常现象进行判断、分析原因,对故障的处理及效果。     

自增强HDPE棒材的结构及力学性能

通过扫描电子显微镜、差示扫描量热法、广角X射线衍射分析与力学性能测试,研究了自增强高密度聚乙烯(HDPE)棒材微观结构特点和力学性能。结果表明,自增强HDPE棒材呈现明显的皮芯结构,表皮的结晶度高达75．88％,芯部的组织和结构与普通注塑试样最相近;与普通HDPE试样相比,自增强HDPE棒材的微晶尺寸和结晶度大幅提高,晶面间距几乎未变化,内部存在大量的微纤结构。制备的自增强HDPE棒材的拉伸强度和弯曲强度分别为220．6 MPa和152．9 MPa,均为未增强试样的近10倍。     

高压结合热处理对大米理化性质的影响

以超高压结合热方法对大米粉进行处理,分析了压力(0.1~700 MPa)、温度(20~60℃)、时间(0~25 min)和加水量[w(H2O)=0~65%]对其主要理化性质的影响。结果表明:随着压力、温度、保压时间和加水量的持续增加,大米粉碘蓝值、溶解度和透明度分别呈现升-降-升-降、降-升-降和一直下降的趋势。凝胶膨胀率随压力变化无显著规律,但随时间、温度和加水量增加而显著降低。在压力和温度分别为600 MPa和45℃时,溶解度和凝胶膨胀率分别为5.46%和8.73 m L/g,都达到最大值,而碘蓝值最小,为0.41。大米粉淀粉糊化度随压力、保压时间、温度和加水量的增大而显著增大,结晶结构由A型向V型转化。碘蓝值与温度和保压时间均呈中等强度正相关关系,与加水量呈极显著正相关关系(p0.01),与压力相关性较小。透明度与压力呈显著负相关(p0.05),与保压时间、温度以及加水量均呈极显著负相关(p0.01),凝胶膨胀率和溶解度与透明度均呈正相关,与碘蓝值呈负相关(p0.01)。     

Enhancing the yield of polycarbosilane synthesis via recycling of liquid by-product at atmospheric pressure

Polycarbosilane (PCS) is a typical ceramic precursor for the fabrication of SiC fibers and SiC matrix composites. However, it is still costly and not widely employed in industry, mainly due to its low yield by typical chemosynthesis methods.In this work, we reported for the first time a novel method to significantly increase the PCS yield from 51.3% to 62.8% by recycling the liquid by-products (LBP), which was mainly made up of low-molecular-weight PCS, as revealed by FT-IR, GPC, and NMR analysis. The results showed that recycling LBP did not alter the chemical structure of the PCS products, making it very promising for mass production and application of PCS at the industrial scale.     

A single crystal of polyethylene crystallized under high pressure

A single crystal of polyethylene about 2 μm thick has for the first time been obtained through high pressure crystallization and studied by X-ray diffraction and scanning electron microscopy. A band of a few μm thickness observed on the fractured surface of high pressure crystallized polyethylene is identified as a single crystal at least several tens of μm wide. Furthermore, a bulk composed of several bands stacked approximately parallel gives hexagonal symmetry in an X-ray oscillation photograph, the oscillation axis being parallel to the end surface of the bands. On the basis of these observations, it is concluded that a thick single crystal in the hexagonal phase splits into several bands on the transition from the hexagonal to the orthorhombic phase; 〈110〉 or 〈010〉 of each band in the orthorhombic phase corresponds to one of three possible a-axes in the hexagonal phase.     

PTT的结构及性能

介绍PTT的结构特征和有关的性能优势及其发展前景。指出PTT的甲基呈螺旋排列,分子链呈"Z"状,易于结晶但不发生晶型转变,使之具有较高的拉伸及回复性,较低的模量,适中的玻璃化温度,良好的抗化学性能及低吸水性等,因而加工条件简单,可纺性好,易于染色。     

高压水射流喷射枪具

介绍高压水射流喷射枪具构造特点及其应用经验.     

平衡磷酸盐处理在高温高压锅炉的应用

对磷酸盐处理和平衡磷酸盐处理两种方式进行对比试验,高温高压锅炉采用平衡磷酸盐处理方式后,运行稳定,水质改善,蒸汽品质提高,节省了给水二次加氨的用量,避免了磷酸盐隐藏现象,溶药次数和强度下降。     

Ammonia removal from effluent streams of wet oxidation under high pressure

The formation of ammonia is inevitable during industrial-scale wet oxidation of wastewater if nitrogen-containing compounds are present. This undesired side-reaction requires additional measures for disposal. Common routes are either the use of noble metal-containing catalysts in the first oxidation step or end-of-pipe treatment. Problems rise for example from the insufficient stability of solid catalysts against hydrothermal impact. As most of the wet oxidation processes run at elevated pressure and temperature, running the heterogeneously catalysed oxidation of ammonia in the gas phase in a downstream reactor could protect the catalysts mainly from leaching and offers an economic alternative by avoiding loss of unused oxygen after depressurisation. This work reports on the oxidation of ammonia with air in steam atmosphere using Cu,Cr-containing supported and bulk catalysts at 235–305 °C and 30–60 bar. A copper chromite catalyst gave best performance (86% conversion at 305 °C, 45 bar, contact time 1 s). The spinel-type phase CuCr₂O₄ seems to be the active phase and shows superior stability. The results indicate that phase behaviour of water strongly influences activity and lifetime of catalysts. Characterisation of the solids (BET, XRD, XPS, ICP) proved that deactivation is mainly caused by leaching of Cr(VI) species from catalysts when the reaction runs near to dew point of water and by loss of BET surface area of supported catalysts due to hydrothermal impact.A member of the EU-funded Coordination Action of Nanostructured Catalytic Oxide Research and Development in Europe (CONCORDE).