胶接接头正拉强度和剪切测试装置的研制

作者研制出可用于金属胶接接头正拉和剪切强度测试的新装置，其结构简单、操作方便、成本低、精度高，适于生产现场的质量控制。     

胶接接头剪切和正拉强度试验方法的分析

分析了胶接接头现行剪切强度和正拉强度测试方法中存在的问题，指出由于应力集中及多种应力的综合作用导致测试值出现较大偏差，提出了胶接接头剪切强度和正拉强度测试方法的改进意见。     

石油发酵尼龙改性环氧胶粘剂的研究

石油发酵尼龙改性环氧胶粘剂是一种胶接强度高和抗冲击性能、耐湿热性能好的胶粘剂。本文研究了该胶粘剂的最佳配方和胶接工艺,测试了其耐湿热性能,讨论了各组份用量(尼龙、环氧树脂、双氰双胺固化剂)、尼龙与环氧树脂配比以及固化条件对该胶粘剂胶接强度的影响.     

一种木材粘合剂胶接强度新型试验装置的研制

设计了一种由基础框架、加载液压千斤顶、测力弹簧、读数百分表和试样夹具组成的木材粘合剂胶接强度试验装置。有限元数值分析与通用材料试验机的测试比较结果表明：该装置可满足JIS K6852标准的要求，且具有结构简单、体积小、测量可靠和便捷的特点。     

碳纤维复材结构网球器械接头的胶接强度性能表征

针对网球器械用碳纤维复合材料胶接连接,以超声机械振动方法胶接处理了网球器械用碳纤维复合材料,并测试分析了碳纤维复合材料胶接强度。结果表明,超声机械振动胶接工艺参数直接影响着网球器械用碳纤维复合材料的胶接强度,其振动时间为21s、振动压力为0.35 MPa、振动位置为27 mm、振幅为57μm时,网球器械用碳纤维复合材料胶接强度最高;相较于未超声机械振动对照组,基于正交实验优化的超声机械振动组的碳纤维复合材料胶接强度更高,且试样破坏后胶层截面位置缝隙非常小,胶接强度分散性较小,胶接性能更加稳定。     

多异氰酸酯涂覆处理对聚乙烯木塑复合材胶接接头耐水性能的影响

采用多异氰酸酯对聚乙烯木塑复合材料进行表面涂覆处理以改善其胶接性能。利用接触角测试、表面形貌观测以及胶接强度和吸水量测试研究了涂覆表面处理对聚乙烯木塑复合材料胶接接头耐水性能的影响。结果表明,涂覆处理后复合材料的胶接强度和接头耐水性明显提高。水浸后聚乙烯木塑复合材料的表面性质发生了改变,随着水浸时间的延长,表面粗糙度增加,表面接触角下降。长时间水浸下胶接接头的吸水量增加,胶接强度下降。水环境下聚乙烯木塑复合材料中木质纤维的吸水膨胀是造成胶接性能下降的主要原因。     

一种修补匣钵或棚板用的胶接剂

研制了一种修补匣钵或棚板用的胶接剂，本文对该胶接剂的干燥胶接强度及温度性能进行了分析。     

橡胶V带底胶联组挤出装置

该装置由炼胶机、供胶机、刀架、输送机、挤出机、冷却水槽、吹干机、速度控制装置、卷取装置联接组成。炼胶机安装于供胶机的前端，冷却水槽设置于吹干机的前端和吹干机联接；吹干机设置于速度控制装置的前端和速度控制装置联接；速度控制装置设置于红外线自动卷取装置的前端和红外线自动卷取装置联接；供胶机设置于炼胶机的后端和炼胶机联接；刀架设置于供胶机上和供胶机联接；输送机设置于供胶机和刀架的后端，     

高温硫化硅橡胶胶粘剂的研究

制备了一种有机硅胶粘剂,该胶粘剂主要由苯基硅橡胶与ＭＱ硅树脂组成,对影响该胶粘剂胶接强度的因素进行了研究。结果表明：该胶粘剂对铝有较好的胶接强度,其剪切强度与ＭＱ树脂的结构有很大关系,随ＭＱ树脂用量的增加而提高,催化剂的种类和用量对胶接强度也有影响。另外,该胶粘剂具有优良的耐高温老化性能以及对聚四氟乙烯较好的胶接性能。     

多异氰酸酯表面处理对木塑复合材胶接耐水性的影响

采用多异氰酸酯对聚乙烯木塑复合材料进行表面处理以改善其胶接性能。利用胶接强度和接触角测试以及SEM、FTIR、XPS等分析方法研究了表面处理对木塑复合材料胶接接头耐水性能的影响。试验结果表明,经打磨并采用多异氰酸酯表面处理后,复合材料的胶接强度和耐水性明显提高。水浸环境下,短期内异氰酸酯处理的木塑复合材料表面变化不大;长期水浸下复合材料的表面逐渐出现微裂纹,表面性质发生改变,胶接强度下降。聚乙烯木塑复合材料中木质纤维的吸水膨胀,是造成水环境下胶接强度下降的主要原因。     

Testing peel adhesion of flexible films: banknote substrates

A custom peel testing device has been developed to measure adhesion strength of flexible thin film layers. The device overcomes the inherent problems of traditional peel machines that are associated with inaccurate peel angle definition and complex sample clamping. To demonstrate its performance, we have compared peel adhesion of currently used paper-based and polymer-based banknotes. Polymer banknotes have shown higher peel strength, which may yield greater durability and ensure increased lifetime in intensive use during circulation.     

Adhesion of underfill and components in flip chip encapsulation

The underfill material is a polymeric adhesive used in flip chip packaging. It encapsulates the solder joints by filling the gap between a silicon die and an organic substrate or board. Within a typical flip chip structure, there are interfaces between the various components, namely, substrate, solder mask, flux residue, underfill encapsulant and die passivation layer, etc. Maintaining a good adhesion condition, both as-made and after temperature/humidity aging, is vital for these interfaces because of the expected performance of the flip chip device, where the underfill material is employed to enhance the reliability of the flip chip interconnect. We have studied the adhesion strength between the various components for different process variables as measured with the lap shear and die shear test configurations. The effects of the assembly factors, i.e. solder mask, flux residue, underfill, and die passivation, etc., were evaluated and the adhesion strength was found to depend greatly on these factors. The die shear strength of a passivated die assembled onto an organic board coated with a solder mask was much higher after using a no-clean flux on the solder mask than for the assembly without such a no-clean flux. The influence of some accelerated aging tests on the adhesion durability was also investigated. A die passivation layer of benzocyclobutene exhibited better capability in retaining the die shear strength than a passivation layer of silicon nitride or polyimide, especially for the initial aging period. The knowledge obtained in this study should provide insights into the interfacial adhesion in the flip chip assembly structure.     

Investigation of Shape Transformations of Vesicles,Induced by Their Adhesion to Flat Substrates Characterized by Different Adhesion Strength

The adhesion of lipid vesicles to a rigid flat surface is investigated. We examine the influence of the membrane spontaneous curvature, adhesion strength, and the reduced volume on the stability and shape transformations of adhered vesicles. The minimal strength of the adhesion necessary to stabilize the shapes of adhered vesicles belonging to different shape classes is determined. It is shown that the budding of an adhered vesicle may be induced by the change of the adhesion strength. The importance of the free vesicle shape for its susceptibility to adhesion is discussed.     

Mechanical effects in peel adhesion test

—Mechanical effects in the peel strength of a thin film have been studied both experimentally and theoretically. It has been found that the adhesion strength measured by the peel test is a practical adhesion (an engineering strength per unit width) and does not represent the true interface adhesion strength. The measured value may represent a multiplication of the true interface adhesion and other work expended in the plastic deformation of the thin film. The contribution of the latter to the peel strength is found to be, sometimes, of the order of 100 times higher than the former. It is found that the major controlling factors in the peel strength are the thickness, Young's modulus, the yield strength, the strain hardening coefficient of the film, and the compliance of the substrate as well as the interface adhesion strength. Even though the true interface adhesion strength is the same, a higher peel strength is obtained if the film is thinner or more ductile under the test conditions reported in this paper. The same effect can be obtained if the substrate is thinner in the case where the substrate is a soft elastic material, or if the substrate is thicker in the case where the substrate is a rigid material.     

Self-assembled monolayer of designed and synthesized triazinedithiolsilane molecule as interfacial adhesion enhancer for integrated circuit

Self-assembled monolayer (SAM) with tunable surface chemistry and smooth surface provides an approach to adhesion improvement and suppressing deleterious chemical interactions. Here, we demonstrate the SAM comprising of designed and synthesized 6-(3-triethoxysilylpropyl)amino-1,3,5-triazine-2,4-dithiol molecule, which can enhance interfacial adhesion to inhibit copper diffusion used in device metallization. The formation of the triazinedithiolsilane SAM is confirmed by X-ray photoelectron spectroscopy. The adhesion strength between SAM-coated substrate and electroless deposition copper film was up to 13.8 MPa. The design strategy of triazinedithiolsilane molecule is expected to open up the possibilities for replacing traditional organosilane to be applied in microelectronic industry.     

Fractal analysis of surfaces roughened by grit blasting

Surfaces roughened by grit blasting influence the adhesion strength of plasma-sprayed ceramic coatings. The average surface roughness has been used to evaluate the surface topography of such surfaces. It is well known that the adhesion strength of ceramic coatings reaches a maximum value at a certain substrate surface roughness. However, this result cannot be understood based on only surface roughness. The blasted surface has fractal characteristics. There are two types of fractal surfaces, which are characterized by self-similarity and self-affinity. Using fractal analysis to evaluate the surface topography of substrates, the fractal dimension was measured for the roughened surfaces. The maximum fractal dimension was attained at a blasting angle of 75°, where the adhesion strength also reached approximately its maximum value. It is concluded that the fractal dimension is a more appropriate measure than the average surface roughness for evaluation of the adhesion strength of ceramic coatings.     

An improved laboratory reattachment method for the rapid assessment of adult barnacle adhesion strength to fouling-release marine coatings

Modifications have been made to the previously described adult barnacle laboratory reattachment method to enhance and improve the overall utility of this technique for rapidly assessing the efficacy of novel fouling-release marine coating technologies. These modifications include the use of an immobilization template to secure barnacles onto the coating surfaces during the underwater reattachment process, the development of a semi-automated push-off device to enable consistent and reproducible force gauge measurements and the implementation of a software tool to measure the diameter of barnacle base plates for adhesion strength calculations. A series of experimental siloxane?Cpolyurethane and control coatings were evaluated with both the original and improved laboratory reattachment methodologies. Significantly higher adhesion strengths were obtained on these coatings using the improved reattachment method. Furthermore, only the improved reattachment method was able to discern significant differences in the performance of the siloxane?Cpolyurethane coatings based on differences in compositional components. In this regard, the siloxane?Cpolyurethane coatings containing the poly-caprolactone end groups attached to the poly(dimethylsiloxane) (PDMS) backbone exhibited significantly higher reattached barnacle adhesion strengths than the aminopropyl-terminated PDMS containing coatings. It was also shown that the utilization of barnacles with 5?C6?mm base plate diameters, rather than 7?C8?mm diameters, significantly enhanced the strength or tenacity of adhesion to the surface of the control coatings. The results of the improved laboratory reattachment evaluation of experimental siloxane?Cpolyurethane and control coatings were in good agreement with barnacle adhesion measurements obtained for the same coatings with static ocean immersion testing in the field.     

Design of a vane mixer with controlled extensional/shear strength ratio and its application for carbon fiber/polyamide 6 composites

In this work, a novel melt mixing method and its corresponding mixing device are developed. The extensional/shear strength ratio of the device can be controlled by adjusting its eccentricity. The structure and working principle of the device are introduced in detail. Carbon fiber (CF)/polyamide 6 (PA6) composites are prepared via this novel mixing device. The influences of eccentricity and mixing time on the morphology, CF length, thermal, mechanical, and electrical properties of CF/PA6 composites are studied. Scanning electron microscopy results show that CFs uniformly disperse in the matrix and interfacial adhesion between CFs and PA6 is improved. It is observed that CF length and its distributions can be optimized by changing eccentricity. The maximum average fiber length is about 351 μm. Differential scanning calorimetry results exhibit that the X_c increases 6.5% when eccentricity is 2 mm. Mechanical test results show tensile strength and modulus increase first and then decrease with the increasing eccentricities or mixing time. Electrical property measurement shows an obvious increase when eccentricity is 2 mm due to good fiber dispersion and long fiber retention length. The experimental results indicate that the novel mixing method and its corresponding apparatus provide an environment-friendly and effective way to prepare polymer-based composites.     

Adhesion between individual components and mechanical properties of natural rubber-polypropylene thermoplastic elastomeric blends

Adhesion between individual components and the mechanical properties of natural rubber (NR)-polypropylene (PP) thermoplastic elastomeric blends with reference to adhesion have been studied. The adhesion strength between the component phases was varied by incorporating a third component, namely ethylene propylene diene rubber (EPDM) or chlorinated polyethylene (CPE), and their effects on the mechanical properties were also studied. It was observed that the level of adhesion between NR and PP is improved by incorporating 20 parts of EPDM or CPE in NR. The mechanical properties of the blends are also improved for a particular composition. The enhancement in the strength properties and modulus of an NR:X:PP (where X is the third component) (70:10:30 or 70:20:30) blend is apparent when a correction due to the hard-phase contribution of the blend is made by taking the ratio of the strength of the composite to the strength of the hard phase or modulus of the blends. When the three-component blends were compared with a 90:30 blend of NR-PP, the role of adhesion played by EPDM or CPE in improving the strength and modulus could be demonstrated. In fact, there is a direct qualitative relationship between the adhesion and the mechanical properties in such composites. The stronger the adhesion, the greater the tensile strength and modulus. The higher adhesion strength is further reflected from the morphology of various blends. Separation of the phases during swelling and subsequent drying is restricted in the systems exhibiting higher adhesion strength between the components.     

Strength of adhesion of primer coat with additives to nickel-chromium alloy in making cermet dental crown

The effect of tin oxide and calcium phosphate on the strength of adhesion of material for an artificial tooth primer coat to the metallic crown is considered. An alternative method for fast determination of the strength of adhesion of metal to ceramics using a Micro Scratch Tester instrument is based on depositing a scratch on a finished coating with a diamond indenter. It is found that the hydroxyapatite additive ensures the optimum adhesion. __________ Translated from Steklo i Keramika, No. 6, pp. 23–25, June, 2006.