溶剂法醇解合成3,3,3-三氟丙基三甲氧基硅烷的研究

以3,3,3-三氟丙基三氯硅烷和甲醇为原料,采用溶剂法醇解合成3,3,3-三氟丙基三甲氧基硅烷,研究了原料配比、N2流量、滴加速度、反应温度及反应时间等因素对合成的影响,运用GC-MS、FT-IR等手段对反应过程和结果进行了综合分析,提出了最佳合成条件.     

3-氯丙基三甲氧基硅烷合成新方法的研究

为提高产率、降低成本,以3-氯丙烯和三甲氧基硅烷为原料、水合三氯化钌为催化剂进行3-氯丙基三甲氧基硅烷的一步合成反应,研究了反应温度、催化剂浓度、原料的加料方式、反应时间、原料的配比对产物收率的影响.结果表明,最佳的反应条件为反应温度80℃、钌催化剂质量分数63 μg/g、3-氯丙烯向三甲氧基硅烷中滴加方式、三甲氧基硅...     

制备HDI及IPTS的新方法

采用毒性较小的固体光气(BTC)代替光气与己二胺和γ-氨基丙基三乙氧基硅烷反应合成了1,6-己二异氰酸酯(HDI)以及γ-异氰酸酯丙基三乙氧基硅烷(IPTS),研究了原料配比、加料温度、反应温度以及反应时间等对实验产物的影响.实验表明,-NH-和固体光气的比例为3:1,加料温度为-20℃,反应温度为60℃,反应时间为3h时能够得到目标产物.用红外光谱和质谱对产物进行了表征,结果显示合成产物具有异氰酸酯的显著特征,纯度较高.因此采用BTC代替光气合成HDI和IPTS是一条切实可行的路线.     

高性能含硅、氟甲基丙烯酸酯共聚物的研究

制备了γ-甲基丙烯酰氧基丙基三(三甲基硅基)硅烷W D、γ-甲基丙烯酰氧基丙基三乙氧基硅烷及其与甲基丙烯酸异冰片酯、甲基丙烯酸异丁酯和含氟甲基丙烯酸酯的共聚物,通过IR、水接触角、吸水率、铅笔硬度和DSC等手段研究了共聚工艺、含氟单体、硅烷单体及催化交联剂对共聚物膜表面性能和力学性能的影响。延迟滴加有机硅单体尤其是W D和含氟单体可使低用量硅氟单体下的共聚物膜表面憎水性大大增强;催化交联剂可使共聚物的玻璃化温度从31.21℃提高到53.12℃,膜的铅笔硬度达到4H以上。     

二乙氧基硅烷与三乙氧基硅烷共聚物的合成及表征

利用盐酸为催化剂,以二甲基乙氧基硅烷、二苯基乙氧基硅烷、γ-(2,3-环氧丙氧)丙基三甲氧基硅烷及水进行水解缩聚反应,制备了具有反应活性的有机-无机杂化有机硅树脂共聚物。通过正交实验研究了催化剂浓度、原料配比、温度及水对树脂产率的影响,得出适宜的合成工艺条件为酸浓度为0.05mol/L、原料配比为1.5∶2.5∶6、温度为70℃、水量为0.1mol。采用红外光谱、核磁对最优配比产物结构进行了表征,表明树脂中具有可反应性基团,其主链为硅氧链。采用GPC分析,数均分子量为43040,分散系数为2.3,分布较宽。     

3-氨丙基三乙氧基硅烷对多壁碳纳米管的化学修饰研究

先用混酸体系(浓硫酸/浓硝酸体积比为3:1)对多壁碳纳米管进行了氧化处理,再利用氧化处理后多壁碳纳米管表面生成的羟基与3-氨丙基三乙氧基硅烷偶联剂(KH550)进行反应,制备了表面有机修饰的多壁碳纳米管。对比了未经改性的原始多壁碳纳米管、混酸处理过的多壁碳纳米管以及经过表面有机修饰的多壁碳纳米管在水中的分散性能。采用红外光谱、透射电镜、拉曼光谱等对化学修饰前后的各种多壁碳纳米管进行了表征和分析。结果表明,硅烷偶联剂KH550已成功地接到多壁碳纳米管上。硅烷化后的多壁碳纳米管保持碳纳米管的结构不变,在水中基本呈现分散状态并可稳定放置20天以上。     

γ-缩水甘油醚氧丙基三甲氧基硅烷合成工艺研究

评价了氯铂酸-异丙醇、氯铂酸-四氢呋喃体系在烯丙基缩水甘油醚和三甲氧基硅烷硅氢加成反应中的催化性能;重点进行了氯铂酸-异丙醇体系催化合成γ-缩水甘油醚氧丙基三甲氧基硅烷的工艺研究.其最佳工艺条件是催化剂:三甲氧基硅烷:烯丙基缩水甘油醚为1.42×10-5:1:1(物质的量),反应温度约85℃,反应时间60min,产物收率约72.58%.用傅立叶红外光谱对化合物进行了表征.     

正硅酸乙酯改性的GPMS有机-无机材料研究

为了考察正硅酸乙酯(TEOS)对材料性能的影响，采用溶胶-凝胶法制备了TEOS改性的γ-环氧丙基醚丙基三甲氧基硅烷(GPMs)有机-无机杂化材料，并用浸渍法使其在玻璃基体上成膜，利用红外光谱、核磁共振谱和原子力显微镜对GPMS-TEOS杂化材料的结构进行了表征，采用差热分析仪、纳米硬度测试仪和扫描分光光度计等对其物化性能进行了测试．结果表明，制得的材料具有纳米级倍半硅氧烷结构，TEOS的含量对杂化体系性能有较大影响；当TEOS质量分数为15％～20％时，杂化体系的热稳定性、硬度和模量等性能最佳，并且具有良好的透光性。     

接枝聚合法制备PANI/CeO_2-APTMS复合材料及其电化学性能

对氧化铈(CeO_2)进行3-氨丙基三甲氧基硅烷(APTMS)修饰得到改性氧化铈(CeO_2-APTMS),并与苯胺(An)发生接枝聚合,制备出CeO_2-APTMS为载体,负载聚苯胺(PANI)的复合材料PANI/CeO_2-APTMS。采用红外光谱、X射线衍射、热重分析及旋转圆盘电化学测试技术,将PANI/CeO_2-APTMS复合材料同未经改性PANI/CeO_2复合材料、纯PANI电化学性能进行比较。结果表明,PANI/CeO_2-APTMS中PANI接枝效果最好,而且CeO_2-APTMS表面接枝PANI与纯PANI结构相同;经过APTMS修饰CeO_2与PANI之间通过价键接枝成PANI/CeO_2-APTMS的起始分解温度在242℃左右,且在200~600℃内的分解速率最慢,PANI/CeO_2-APTMS表现出很好的热稳定性;PANI/CeO_2-APTMS复合材料修饰电极在65g/L Zn~(2+),150 g/L H_2SO_4的硫酸锌体系中,通过循环伏安测试其具有良好峰对称性以及最高阳极峰电流,极化曲线测试对比3类修饰电极时发现在不同转速下PANI/CeO_2-APTMS/GC修饰电极的析氧电位值均偏低,体现出良好的稳定性及析氧电催化活性。     

聚环氧基苯基硅氧烷功能微球的合成研究

以苯基三甲氧基硅烷(PTMS)和γ-缩水甘油醚氧丙基三甲氧基硅烷(KH560)为原料,通过溶胶-凝胶法制备粒径介于1.13.8μm的聚环氧基苯基硅氧烷微球,研究了NH4OH浓度、油水比(O/W)、单体配比以及反应温度等条件对微球形态和组成的影响。结果显示将NH4OH的浓度控制在0.01~1.28wt%,投料油水比在1/2到1/30,KH560占总单体含量在0~20mol%之间,可以有效制得微球。随着PTMS/KH560、O/W比值的下降,以及NH4OH浓度的增加,微球粒径变小。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。