一种研究迁移现象的新方法--干涉法

提出了一种新的研究测试高聚物体系中小分子物质迁移的方法——干涉法。阐述了该方法的原理，建立了数学模型，并进行了误差分析。该方法切实可行，误差在合理范围之内。     

聚氯乙烯增塑剂的吸收行为

通常,认为增塑剂的吸收过程是由扩散机理引起的。在与高聚物的亲合力方面,增塑剂有一种介于溶剂与非溶剂之间的性质。譬如,如果一高聚物能无限量地吸收一种液体,并因此而被溶介,那末,该液体归进为这种高聚物的溶剂一类。相反,如果一种高聚物完全不能吸收该液体,则该液体称为非溶剂。而增塑剂是一种有限度的溶解高聚物的液体。     

数字全息法测量液相扩散系数实验研究

采用数字全息干涉法测量了25℃乙二醇-水物系的扩散系数。详细介绍了实验方法以及2种处理干涉图像获得扩散系数的方法,即横条纹法和弯条纹法。通过测量25℃时0.33 mol/L KCl溶液的扩散验证了实验的精确性。分别用2种方法获得了6个不同质量分数下的乙二醇-水物系的扩散系数,并与文献值进行了对比。结果表明,弯曲条纹法的平均相对偏差是1.3%,比水平条纹法的1.7%小,同时,弯曲条纹法的平均标准偏差更小,说明波动更小。     

手工高分子薄膜材料拉伸试验研究

文章主要分析了高聚物薄膜的拉伸过程,研究了在不同加载速率下低密度聚乙烯薄膜纵向拉伸强度和断裂伸长率的变化规律。实验结果表明:用自制的手动拉伸仪器拉伸高聚物薄膜时,可以清楚的看到其屈服过程,并能分辨出横向与纵向拉伸现象的差别,而用机器拉伸时,无法明显观察到高聚物薄膜拉伸的整个过程,手动拉伸有助于观察与教学。     

激光全息干涉法测量液相质扩散系数数字图像处理的研究

用He-Ne激光器、CCD和图像采集系统等仪器设备,搭建了数字激光全息干涉法测量液相质扩散系数的实验系统,并测试获得了浓度为0.33 mol/l KCl水溶液在298.15 K温度下的全息干涉图像,采用了图像增强、全息干涉条纹图再现及相位展开等数字图像处理过程的关键技术对全息干涉图进行处理,得到了相位展开后物光相位差,经换算后获得了该溶液的质扩散系数.为化工工程上研究替代制冷荆急需的质扩散系数测量提供了有效的方法.     

红外ATR光谱法与紫外光谱法研究高聚物老化

用红外ATR光谱法和紫外光谱法研究了聚丙烯酸酯类和丙烯酸丁酯—苯乙烯共聚物的老化过程。结果表明,这两种方法能有效地研究高聚物老化的动力学过程,在光、热、氧的作用下,高聚物的侧酯基和部分主链断裂,聚苯乙烯成分能延缓侧酯基的断裂。由试样经耐候试验机及氮分子激光两种老化处理的结果表明,后者导致高聚物的光降解速率比前者高9个数量级,因此,氮分子激光老化是一种研究高聚物光降解的好方法。     

溶解度参数及其应用

在涂料工业中,经常将涂料用的树脂溶解在适当溶剂中,並稀释到一定的粘度,以适合于施工应用。那么如何选择树脂的良溶剂呢?以前,人们或者凭借经验,或者根据极性相近便可互溶的原则来选择溶剂,这不免带有很大的盲目性。为了获得研究和加工应用的高聚物溶液(如涂料用树脂溶液等),必须对高聚物的溶解过程及其规律有一个清晰的了解。这是一个具有理论意义和实用价值的重要课题,然而却一直没有很好     

HYCAR组成对它与NC相容性的影响

利用静态溶剂吸附法测试含氮量为 12 .5 %的硝化棉和丙烯腈基团含量不同的丁腈橡胶的各种混合体系 Gibbs自由能。分析结果表明 :随着橡胶中丙烯腈比例增大 ,这两种高聚物共容区逐渐扩大 ,当橡胶中丙烯腈基团含量达到 40 %时二者完全相容。     

溶液聚合法合成油溶性减阻剂研究——减压蒸煮法脱除溶剂

采用减压蒸煮法脱除溶液聚合法合成油溶性聚α-烯烃减阻剂中的溶剂,对过程中溶剂脱除规律进行了考察。用GPC对减压蒸煮前后聚合物的相对分子质量分布进行了表征,用室内模拟环道评价装置测定了减压蒸煮前后聚合物的减阻效果。实验结果表明,原料溶剂质量百分数为70%的点,理论计算减阻率达到62%,溶剂脱除率94%,脱溶剂后减阻率达55%。GPC分析结果表明蒸煮过程对高聚物的高分子部分影响很小,环道测试表明减压蒸煮法能够脱除90%以上的溶剂,而减阻率仅减少约10%,具有工业化价值。     

用状态方程改进的高聚物中溶剂扩散系数预测模型

将Simha-Somcynsky状态方程引入Vrentas-Duda自由体积理论模型,提出改进的高聚物-溶剂体系扩散系数模型,计算常压下橡胶态高聚物中有机溶剂扩散系数对浓度和温度的依存关系.利用高聚物结构单元的范德华体积导出高聚物自由体积分数表达式,通过Simha-Somcynsky方程求取高聚物体积以及对溶剂分子扩散有效的自由体积,避免原模型中繁琐的高聚物粘弹性实验测定和回归高聚物自由体积参数,提高了自由体积理论的预测能力.使用改进的模型预测了苯、甲苯、乙苯和三氯甲烷在聚苯乙烯、聚异丁烯和聚醋酸乙烯酯中的自扩散系数和互扩散系数,计算结果表明改进的自由体积模型具有较高的预测精度.     

混凝土梁加固后的新旧混凝土界面力学性能变化

以破旧建筑物纤维增强复合材料加固法为例,基于界面粘附强度的理论分析,配合剥离试验来求出加固界面破坏时的界面破坏能G.通过采用有限元方法计算出不同剥离角度的GⅠ、GⅡ的比值,然后进一步利用研制的双L型梁试验,来测量加固界面剥离的临界剥离力,从而验证剥离试验的结果.研究结果显示,剥离试验中造成混凝土与纤维增强复合材料贴片界面破坏的剥离力P,随着剥离角度α的增加而越来越小.但是由理论公式所推算出来的界面破坏能G,其变化并无固定的趋势,因此G值与P和α并非为简单的线性关系.另外双L型梁试验所得到的临界剥离力,会随着施力的位置改变而变化,同时临界剥离力P也随着施力点与支承距离的增加而减少,这与有限元程序计算的结果大致类似,本文研究对衡量老旧建筑物的加固设计效果提供了重要的参考.     

AFM Study on the Interactions Across Interfaces Containing Attached Polymer Chains

Summary: Interactions between surfaces with attached polymers are very common in both biological and engineering fields. These types of interactions are critical in processes such as coagulation and flocculation in mineral processing, biological recognition in metabolic processes and stress transference in polymer composites, among others. Although many mechanisms have been proposed to explain phenomena occurring at the interfaces on a molecular level, few experimental procedures can give direct information about them. In this work, interactions occurring at interfaces containing attached polymer chains, such as the ones that are present in polymer composites, were studied by using AFM. In order to identify the effect of the structure of the interface on phenomena such as stress transference and energy dissipation, polymers with different molar mass, areal density and chemical architecture were synthesized and attached to substrates and AFM cantilevers. Force‐distance curves, obtained by AFM, provided some fundamental information about the mechanisms involved when polymers attached to different surfaces interact. Results showed that chains grafted on different surfaces can interact via entanglements and intersegmental bonding. Based upon the application of the AFM modified technique, interfaces containing polymers, such as in polymer composites, can be designed and optimized through the manipulation of its structure to achieve new roles in the performance of systems.

     

基于模糊图像的气液旋风分离器液滴粒度、浓度、速度在线测量

为了对气液旋风分离器进出口液滴粒径、浓度、速度进行测量,研制了一套基于模糊图像测量原理的图像法颗粒粒径、浓度、速度的在线测量系统。具体介绍了测量原理和该系统构成。基于模糊图像处理方法可以得到视场中颗粒粒度与速度信息,结合镜头景深还可以得到流场颗粒浓度。测量系统由图像采集系统、位移控制系统与图像处理系统组成。该系统已被成功安装在某气液旋风分离器实验台上,现场测量结果表明,该系统与光散射颗粒测量方法相比,避免了反演过程,可以得到更高的粒度分辨率,且可以实现实时在线多参数测量,具有较大的优势。     

A comparison of soot nanostructure obtained using two high resolution transmission electron microscopy image analysis algorithms

The present work addresses the validation process of an in-house developed image analysis tool to extract fringe length, tortuosity, and separation from high resolution transmission electron microscopy images of carbonaceous materials. In order to validate the algorithm, we compare fringe properties that are extracted from high resolution transmission electron microscopy (HRTEM) images through (1) the in-house developed tool (new algorithm) and (2) a tool that has been validated and published (previous algorithm). X-ray diffraction and Raman spectroscopy are used to crosscheck the results for fringe length and fringe separation extracted from the HRTEM images. The algorithm of extracting fringe tortuosity is validated by the images of two disordered soot samples, and a heat-pretreated, highly-ordered sample. Tortuosity results are compared with the results of fringe separation. These comparisons validate the algorithm for extracting fringe tortuosity and confirm that tortuosity is an indicator of the degree of disorder within the carbon framework. Statistical results for each property extracted from the HRTEM images by the newly developed image analysis tool are presented in the form of a histogram and characteristic values (mean and median). The characteristic values quantitatively distinguish between the different carbon nanostructures of various soot samples.     

Application of fringe field capacitance sensor for the study of water permeation in organic coatings

Water permeation in organic coatings can be monitored by measuring the capacitance change in coatings. A new method of measuring water content in organic coatings using a miniature fringe field capacitance (FFC) sensor is described in this paper. The FFC sensor comprises two planar interdigitated electrodes on a dielectric substrate which is connected to a measuring circuit. Coating capacitance is measured by measuring the sensor capacitance when it is in contact with the surface of the coating. Sensor capacitance is theoretically calculated based on IDC capacitor theory for various sensor geometrical parameters at different water ingression levels in the coating. The computed sensor capacitance is validated with experimental values of five miniature sensors which are fabricated by lithography. The calibrated FFC sensor is used to monitor the water permeation profile in the coating, and the results are compared with that of electrochemical impedance spectroscopy technique. The technique provides scope for developing a portable, hand-held, and noninvasive technique to measure water permeation in organic coatings in the field.     

Quantitative evaluation of active based adhesion in Aggregate-Asphalt by digital image analysis

Moisture damage has become one of serious distresses to reduce stability of pavement structure and service life. One of the most essential reasons for moisture damage is insufficient adhesion between asphalt and aggregate. Most conventional methods for evaluating adhesive characteristic are subjective and empirical and adhesion results are seriously affected by tester's operation habit and judgment. Meanwhile, active adhesion mechanism was not considered in most conventional methods. This study designed an active adhesion based test method, named active adhesion evaluation method (AAEM), to make up for the lack of research on active adhesion and eliminate the subjective operation in boiling process. Boiling water test was performed on basalt and steel slag aggregates for comparison with AAEM. Digital image processing was used for quantitative detection of adhesive characteristic. Results show that digital image processing can accurately and effectively measure asphalt coating ratio. Mixing time of 90?s, and asphalt content of 2.5% were finally selected as the optimum AAEM test parameters. The variance and standard deviation of coating ratios of AAEM are much smaller than that of boiling water, whether it is steel slag or basalt, indicating that the AAEM is indeed an effective method for measuring coating ratios of aggregates. The distinction of coating ratios for basalt and steel slag can be amplified by AAEM compared with boiling method.     

应用数字图象分析处理聚丙烯及其共混物球晶的生长和形态

本文主要介绍了数字图象处理技术在聚丙烯及其共混体系球晶径向增长速率测定和形态研究方面的应用.这种方法与以往方法相比,最大的特点就是它的可靠性、重现性及操作上的简便,因而成为一种新的测量球晶径向增长速率的方法.本文主要研究了PP及PP/PS、PP/PBT共混体系.研究结果表明,数字图象处理技术在聚合物结晶研究方面是一种非常有价值的工具.     

Electrical Properties and Defect Structure of Zirconia: II, Tetragonal Phase and Inversion

The defect structure of tetragonal zirconia was investigated by measuring the temperature and oxygen partial pressure dependence of the electrical conductivity and the electronic transference number. Tetragonal zirconia was a mixed electronic and ionic conductor under all conditions studied. The n -type electronic conductivity observed at high temperatures and low oxygen partial pressures was interpreted on the basis of a defect model involving fully ionized oxygen vacancies. The conductivity change associated with the monoclinic ⇒ tetragonal phase transformation was isothermal, but the rate of change was a function of the thermal history and the method of preparation of the sample.     

NMR characterization of penetrants in high permeability polymers

Spectra of xenon-129 sorbed into two high permeability polymers are reported. The polymers are the copolymer of tetrafluoroethylene and 2,2-bis(trifluoromethyl)-4,5-difluoro-1,3-dioxole as well as poly(1-trimethylsilyl-1-propyne). At room temperature, the xenon-129 shifts are smaller than in conventional glassy polymers. The smaller xenon-129 shift indicates the presence of larger sorption sites in high permeability polymers relative to conventional polymers. The temperature dependence of solubility in these polymers is drastically different from the behavior in conventional polymers. There is a rapid exponential increase in solubility in high permeability polymers as temperature decreases corresponding to a large negative enthalpy change on sorption and it is this increase in solubility which leads to a large increase in shift with decreasing temperature. Pulse field gradient (PFG) determinations of the self-diffusion constant are made for xenon, propane, pentane and a decafluoropentane in the copolymer. Rapid diffusion is observed as well as a dependence of the apparent diffusion constant on the time scale of the PFG experiment. The translational mobility of smaller simpler moieties depends less on the time scale or equivalently, the length scale of observation in the PFG NMR experiment. For larger, more complex species, the interconnectedness of high free volume domains plays a role in reducing the apparent diffusion constant as the time of measurement increases.