碳纳米管导静电涂料导静电性能的影响因素

目前,导静电涂料的导电介质多以碳系和金属氧化物为主,不能兼顾涂料的防腐蚀与导电性能,对以碳纳米管(CNTs)作为导电介质和以环氧改性有机硅树脂作为导静电涂料基体树脂的研究均较少.利用环氧树脂改性有机硅低聚物合成了改性树脂,采用红外光谱对产物进行了表征,研究了碳纳米管含量、酸化处理、固化剂、分散剂含量对由CNTs制备的导静电涂料涂膜的导静电性能的影响.结果表明:CNTs含量对提高涂膜导静电性能有影响,CNTs含量为2.0％时导静电性能很好;CNTs酸化处理后涂膜的导静电性能得到明显提高;固化剂聚酰胺650含量为30.0％时,涂膜固化性能和导静电性能最优;分散剂能很好地提高CNTs分散性能,十二烷基苯磺酸钠/改性树脂(质量比)和十八醇/改性树脂(质量比)均在2.0％时达到其最佳效果.     

无毒型低表面能海洋防污涂料的研制

为研制符合环保要求的无毒防污涂料,通过氟碳树脂与丙烯酸树脂的物理共混改性,探讨了两种树脂的最佳配比参数;同时通过更改颜料体积浓度(PVC)参数进行试验对比,分析了涂料中颜填料不同组分的变动对涂膜表面能及耐腐蚀等性能的影响,并最终确定涂料配方,制备出了无毒型低表面能海洋防污涂料.     

氨基硅油改性丙烯酸树脂防污涂料的制备与性能

环境友好型有机硅改性丙烯酸树脂的合成及其用于海洋防污涂料的性能研究很有意义。以氨基硅油为原料,通过开环加成改性甲基丙烯酸缩水甘油酯(GMA),再与其他丙烯酸单体自由基聚合制备出氨基硅油改性丙烯酸树脂,借助FT-IR对其结构进行了表征,并以改性丙烯酸树脂为防污涂料成膜物制备了兼具自抛光特性/低表面能特性的防污涂料,考察了氨基硅油用量对涂料涂膜的附着力、柔韧性、接触角和表面能等的影响。结果表明:当氨基硅油用量为1%时,涂膜综合性能达到最佳,附着力、柔韧性达到一级,抗冲击强度≥50 kg·cm,硬度达到2 H,接触角为99.6°,表面能为23.3 m N/m;结合实海挂板试验显示,改性的防污涂料具有良好的防污性能。     

无溶剂纳米SiO2改性环氧涂料的制备及涂覆建筑护栏施工要素

为了克服现有环氧树脂增韧改性时韧性增强而环氧树脂本身优异性能降低的技术难题,并解决环氧树脂的高柔韧性和无溶剂化的矛盾,先以带环氧基团的硅烷偶联剂KH-560改性纳米SiO₂,之后与液体环氧树脂E-51进行化学接枝反应,制得改性环氧树脂,再加入活性稀释剂和低黏度固化剂制备无溶剂纳米改性环氧涂料并对其配方进行优化,获得了柔韧性和防腐蚀性能俱佳的改性环氧涂料。以改性环氧涂料为底漆,以丙烯酸聚氨酯涂料作为面漆,详细介绍了复合涂层体系在不锈钢建筑护栏防护时的施工工艺和作业方法。结果表明:改性纳米SiO₂用量为环氧树脂E-51的2%³%时,纳米改性环氧涂料的柔韧性和防腐蚀性能优良;活性稀释剂用量为纳米改性环氧树脂的30%⁴0%,固化剂选用酚醛树脂固化剂NX-5198,附着力促进剂选用环氧基硅烷KH-560,用量为纳米改性环氧树脂的3%时,得到的改性环氧涂料施工、涂膜性能优良。     

SiO2改性低表面能纳米结构无毒海洋防污涂料

以合成的有机硅改性丙烯酸树脂为主要成膜物质,在颜填料不变的基础上添加纳米SiO2,制成了低表面能纳米结构无毒海洋防污涂料,讨论了树脂用量和纳米SiO2对涂膜附着力及其与液体接触角的影响,分析了低表面能防污涂料的表面结构.结果表明,树脂用量为25%～30%时,涂膜的附着力为1级,涂膜与水的接触角为150°,涂膜表面为纳米-微米阶层状结构.     

碳纤维体系导电涂料的制备工艺

研制了一种以丙烯酸酯类树脂为基料的改性碳纤维体系导电涂料.用单因素方法确定改性碳纤维/树脂质量比,偶联剂的种类、用量以及添加方式、涂料的固化工艺等方面对涂料电性能的影响关系,然后用正交实验进一步优化各因素对涂膜导电性能的影响,确定了制备碳纤维体系导电涂料的最佳工艺条件为:改性碳纤维/树脂质量比为0,7,钛酸酯偶联剂TMC-102采用预处理用量为1%(wt,下同)和直接加入用量为1.5%相结合,制得的导电涂料综合性能较好;固化温度为50℃下固化20min,涂膜厚度为150μm时,其表面电阻率达到1.02Ω/sq.     

PU/PA核壳乳液/水分散异氰酸酯交联成膜机理及其性能研究

制备了双组份水性聚氨酯木器涂料,探讨了羟基组分聚丙烯酸酯(PA)含量和固化剂用量对涂膜强度以及耐溶剂性、硬度和抗冲击性能等影响,并根据粒径分析和透射电子显微镜(TEM)等测试方法研究了羟基聚氨酯-丙烯酸酯复合乳液(PUA)和固化剂的反应情况及树脂结构。结果表明,PA含量为15%,固化剂加入量为5%时得到稳定性、涂膜硬度、韧性、耐溶剂性较优的水性聚氨酯木器涂料。     

环氧改性丙烯酸系亲水涂料的研究

对环氧改性丙烯酸系亲水涂料的制备和性能进行了研究.采用水溶液聚合法合成了亲水性丙烯酸树脂,讨论了亲水性单体用量及配比、聚合物的pH值对涂膜亲水性和耐水性的影响,研究了交联剂、改性树脂、乳化剂对涂膜综合性能的影响,并从理论上进行了分析、确定了各成分的配比.试验结果表明,涂膜的亲水性和耐水性能达到较好的均衡,改性后涂层的耐蚀性和附着力得到提高.     

不同氟含量的苯丙树脂及防污涂料的性能研究

采用具有低表面能特性的有机氟单体对苯丙树脂进行改性合成,探讨了氟单体用量及软硬单体比例对树脂性能的影响,用接触角检测仪对涂膜表面与水的接触角进行了测量,并对涂膜的附着力、冲击强度等各项常规性能进行了综合检测,同时进行了实海挂板试验。结果表明,当氟单体含量为17.3%、软硬单体比值为0.46时,树脂性能较好,对应的防污涂料防污性能也最佳。此时涂料涂膜与水的接触角是145.5°,附着力等级1级,在50cm垂直高度下重锤冲击无裂纹。     

有机氟改性丙烯酸树脂的合成及研究

使用不同的有机氟单体对丙烯酸树脂进行改性,合成了具有低表面能性质的有机氟改性丙烯酸树脂;对树脂进行了红外和分子量检测,并测试了涂膜的附着力、抗冲击力、接触角等各项性能;研究了不同的氟单体种类、氟单体用量以及合成工艺对树脂性能的影响。结果表明,氟单体对丙烯酸树脂进行低表面能改性效果明显,其中含有叔碳原子和甲基结构,分子中含有12个F的G04单体效果最为理想;采用滴加氟单体工艺能够显著增大树脂的接触角;当氟单体G04用量在16.7%时,树脂与水的接触角最大可达104.5°。     

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)。