有机硅密封胶硫化体系的研究进展

对有机硅密封胶的硫化体系进行了综述,划分出脱酮肟型、脱醇型、脱酸型、脱羟胺与脱酰胺型双体系以及其他类型密封剂硫化体系,介绍了不同硫化体系有机硅密封材料的应用及其对其性能的影响,并就交联反应、硫化促进剂的不足之处进行了展望。     

时间对缩合型RTV有机硅密封胶硬度的影响

跟踪检测了缩合型室温硫化(RTV)有机硅密封胶硫化后在标准条件、室内和室外暴露三种环境下24个月的硬度.结果发现,缩合型RTV有机硅密封胶的硬度在硫化12个月之内随时间的延长有增长趋势,室外暴露下增长最大,室内放置时增长次之,标准条件下放置时增长最小;有机硅密封胶的硬度值在硫化6～15个月内有明显变化,随着时间的推移,变化越来越小,一年以后基本趋于稳定;脱醇型双组分有机硅结构密封胶和酸性大板玻璃用有机硅密封胶的硬度增长最小,脱醇型单组分有机硅结构密封胶的硬度增长次之,酮肟型有机硅密封胶的硬度增长最大.     

无腐蚀脱酮肟型RTV-1有机硅密封胶的制备

为了降低脱酮肟型单组分室温硫化(RTV-1)有机硅密封胶对铜和聚碳酸酯(PC)基材的腐蚀性,在其中添加了活性硅酸镁吸附剂和酮肟清除剂。研究了活性纳米硅酸镁吸附剂和酮肟清除剂对脱酮肟RTV-1密封胶性能的影响。结果表明,密封胶中加入活性纳米硅酸镁吸附剂和酮肟清除剂能有效地吸收密封胶硫化过程中释放出的丁酮肟,抑制丁酮肟水解产生的碱性环境,大大减轻密封胶对铜基材和PC材料的腐蚀;同时能加速胶层的深层硫化速度,且对其表干时间和力学性能影响不大。     

硫化类型对RTV-2氟硅密封胶性能的影响

以自制的端羟基氟硅共聚物为基础聚合物,ZnO为填料,二月桂酸二丁基锡为催化剂,分别采用正硅酸乙酯、甲基三丁酮肟基硅烷(D31)、甲基三乙酰氧基硅烷(D17)为交联剂,制得脱醇型、脱酮肟型和脱醋酸型双组分室温硫化(RTV-2)氟硅密封胶。探讨了硫化类型对氟硅密封胶表干时间、耐热空气老化性能、耐油性能、热失重性能以及动态热机械性能的影响。结果表明:脱酮肟型氟硅密封胶具有良好的综合性能:玻璃化转变温度为-114℃;热质量损失率为10%时的温度达到482.2℃;经200℃×24 h老化后,拉伸强度降低4%,拉断伸长率降低7%。     

上海汉司脱丙酮型室温硫化(RTV)硅橡胶的应用特点

正单组分RTV(室温硫化)硅橡胶的硫化反应是通过其与空气中的水分发生反应而硫化成弹性体的。根据交联剂与端羟基聚二硅氧烷进行交联反应时生成副产物的种类,可将缩合型单组分RTV液体硅橡胶分为脱酮肟型、脱醇型、脱丙酮型、脱乙酸型、脱胺型和脱酰胺型等6种。脱酮肟型、脱醇型是较常见的品种:前者粘     

交联剂用量及添加方法对透明脱酮肟型单组分有机硅密封胶性能的影响

以α,ω-二羟基聚二甲基硅氧烷(107硅橡胶)、甲基硅油、白炭黑、混合酮肟型交联剂、偶联剂和催化剂等为原料制成单组分中性透明脱酮肟型有机硅密封胶。研究了交联剂用量及添加方法对中性透明脱酮肟型有机硅密封胶的透明度及物理性能的影响,同时对其储存稳定性和耐高温高湿后的性能进行了研究。当107硅橡胶为100份,混合交联剂选择6份时,得到的有机硅密封胶具有较快的表干时间,深度硫化速度,同时其硬度和强度适中,且老化后的性能变化不大,透明度也较优异,在实际应用中具有良好的适应性。     

白油对脱酸型有机硅密封胶性能的影响

以黏度80 000 mm2/s的107硅橡胶为基础聚合物、气相法白炭黑为填料、白油为增塑剂,添加醋酸型交联荆、催化剂、助荆,配成脱酸型单组分室温硫化有机硅密封胶.考察了白油用量对脱酸型有机硅密封胶性能的影响.结果表明,随着白油用量的增加,有机硅密封胶的渗油性、挤出性、表干时间、拉断伸长率增加,硬度、拉伸强度、模量下降;...     

二甲基硅油用量对RTV硅橡胶性能的影响

以自制的不同类型室温硫化(RTV)硅橡胶为样品,考察了二甲基硅油用量对其拉伸强度、拉断伸长率、撕裂强度、剪切强度、电气强度、表干时间和硬度的影响。结果表明,随着二甲基硅油用量的增加,硅橡胶的拉伸强度、撕裂强度、剪切强度、硬度逐渐降低,而表干时间和拉断伸长率逐渐增加,电气强度基本保持稳定。此外,脱醇型RTV硅橡胶的拉断伸长率、表干时间受二甲基硅油用量的影响大于脱酮肟和脱酸型;而就拉伸强度、撕裂强度、剪切强度而言,二甲基硅油用量对脱酸型RTV硅橡胶的影响更大;二甲基硅油用量对RTV硅橡胶硬度的影响程度相当。     

户外火力发电厂用单组分室温硫化硅橡胶的研制

以α,ω-二羟基聚二甲基硅氧烷、甲基三丁酮肟基硅烷、乙烯基三丁酮肟基硅烷、气相法白炭黑、气相法二氧化钛(TiO2PF2)、有机锡催化剂等为原料,制得户外火力发电厂用单组分脱酮肟型室温硫化硅橡胶,考察了耐酸碱填料种类及用量、耐热剂用量对密封胶耐酸碱性和耐热性的影响.结果表明,以沉淀法硫酸钡作为填料制得的密封胶耐酸碱性能较...     

耐油性单组分酮肟型有机硅密封胶的研制

研究了脱酮肟型有机硅密封胶耐油性的影响因素,比较了不同交联剂、填料对密封胶耐油性的影响。     

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。     

几种乙炔加压设备性能的比较

阐述并比较了几种加压设备在乙炔加压清净过程中的性能和特点。     

三种煤样燃烧热的测定

本文通过三个厂家提供的三种煤样燃烧热的测定,由测定结果综合得出3号煤样燃烧最完全、燃烧热也最大,是三个煤样中最好的一种。     

Semi-empirical equation of state of metals. Equation of state of aluminum

A semi-empirical equation of state for metals is described. Its capabilities are demonstrated by the example of the equation of state for aluminum. New experimental data are presented on the location of the isentrope of aluminum for unloading from the state at p = 229.71 GPa on the shock adiabat to an aerogel (SiO₂) of density 0.08 g/cm³. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008.     

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。     

小议汽车涂装工艺设计对涂装成本的影响

论述了涂装工艺设计对涂装设备投资、涂装生产成本的影响。     

Measurement of the gradient of viscosity with composition of mixtures of non-ideal gases

A perturbation viscometer is a differential capillary viscometer that measures the logarithmic viscosity gradient of the viscosity-composition curve for gas mixtures. Measurements are made at different gas mixture compositions. Integration of the logarithmic viscosity gradients measured over the full composition range gives the mixture viscosity relative to the viscosity of one of the pure components of the gas mixture. This method is attractive because, for measurements of equal precision, integration of the gradients is potentially an order of magnitude more precise than measurement of the viscosities directly. It can also work at high and low temperatures and perhaps high pressures.The perturbation viscometer has been used to make measurements on ideal gas mixtures at ambient and elevated temperatures. The situation is more complicated when the gas mixtures are non-ideal. Extra effects due to density differences, molar volume change on mixing and differential thermal expansion may be measured in addition to the desired viscosity change producing systematic errors in the results. Thus, a more sophisticated apparatus is required. The standard perturbation viscometer has been modified to separate out the extra effects to permit measurement of the true change in viscosity. In addition, the theoretical operation of the modified apparatus has been revised to account for the design changes to permit calculation of the viscosity-composition profiles from the results.The apparatus has been tested using helium-HFC-125 mixtures and two new viscosity-composition profiles are presented for these mixtures at 23 and . Internal consistency tests have been used to confirm that the data produced are of high quality with an estimated uncertainty in the viscosity ratio data at of 0.9% and at of 1.5%.     

Calorimetric and Computational Study of Enthalpy of Formation of Diperoxide of Cyclohexanone

A thermochemical rather simple experimental technique is applied to determine the enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented with suitable theoretical calculations at the semiempirical and ab initio levels. A particular satisfactory agreement between both ways is found for the ab initio calculation at the 6–311G basis This set level. Some possible extensions of the present procedure are pointed out.     

塔设备改造选型的分析

就当前扩产增容中塔设备设计和改造时板式塔和填料塔的选型问题加以分析。在评述目前国内常用的几种塔板和新型填料之后，着重介绍一种新型塔板（导向梯形浮阀塔板）和一种新型填料（波环填料——乾隆帕克）。     

Effect of degree of deacetylation of chitin on the properties of chitin crystallites

In the present article, chitin from crab shell was systematically deacetylated using a NaOH treatment with control of the reaction time. The degree of deacetylation, monitored using solid-state NMR, revealed that the reaction was pseudo-first order. Based on this, swollen and NaOH-saturated particles are proposed as the reaction system. The weight loss of the partially saponified and neutralized samples after HCl hydrolysis increased linearly with the degree of deacetylation. The crystallinity of the samples was found to increase after acid hydrolysis. According to conductimetric titration, the surface charge density of the crystallites, after acid hydrolysis, was found to increase with base treatment time. The effect of surface charge on the formation of a chiral nematic phase, due to the rodlike nature of the crystallites, was explored. These results show that because the contribution of charged particles to the ionic strength was significant the double layer compression was affected, especially since the surface charge density was close to the Manning limit. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:373–380, 1997