Delamination of filler-incorporated automotive epoxy adhesives from different steel substrates upon exposure to distilled water and NaCl solutions under applied bending stresses

Delamination of four filler-incorporated automotive epoxy adhesives from five different steel substrates was studied using a three-point bending device. The bent specimens were exposed to distilled water and NaCl solutions with different concentrations from 1–5 weeks. It was found that the degree of adhesive delamination increased with the concentration of the NaCl solution, and with the magnitude of the applied bending stresses. The harder the adhesives, or the higher the content of the fillers in the adhesives, the lower was the degree of the adhesive delamination. In addition, the rank of the steel substrates in terms of their bonding resistance against adhesive delamination was determined. It is believed that the adhesion between the adhesives and the steel substrates is governed by the surface roughness of the steel substrates.     

Reactive calcium-phosphate-containing poly(ester-co-ether) methacrylate bone adhesives: setting, degradation and drug release considerations

This study has investigated novel bone adhesives consisting of fluid photo-polymerizable poly(lactide-co-propylene glycol-co-lactide)dimethacrylate (PGLA-DMA) mixed with systematically varying fillers of β-tricalcium phosphate (β-TCP) and monocalcium phosphate monohydrate (MCPM), for the delivery of an antibacterial drug chlorhexidine (CHX). All formulations were found to polymerize fully within 200 s after exposure to blue light. In addition, water sorption by the polymerized materials catalyzed varying filler conversion to dicalcium phosphate (DCP) (i.e. brushite and monetite). With greater DCP levels, faster degradation was observed. Moreover, increase in total filler content enhanced CHX release, associated with higher antibacterial activity. These findings thus suggest that such rapid-setting and degradable adhesives with controllable drug delivery property could have potential clinical value as bone adhesives with antibacterial activity.     

Effects of chemical treatments of hybrid fillers on the physical and thermal properties of wood plastic composites

Hybrid filler reinforced composites are considered as a high performance materials, but limited numbers of researches on hybridizations of wood fibers and mineral fillers were reported. Generally, high amount of filler content in composites can lead to the reduction of interfacial adhesion between matrix polymer and fillers, and it limits their applications. In this study, we measured the changes of tensile strength, water absorption, and thermal properties of composites after chemical treatments to wood fibers and mineral fillers. Coupling agent had its own optimum amount for wood fibers and talc to obtain the highest tensile strength. Talc addition showed little effect of the tensile strength with alkali treated wood fibers. Talc addition and silane treatment showed opposite effects on water absorption. Melting enthalpy was decreased by addition of the fillers because of the reduced amount of the crystallizable resin and because of the interference of the fillers for crystallization process.     

基于废弃包装纸的纳米纤维素制备及其对淀粉胶黏剂性能的影响

目的探索纸包装废弃物的高附加值利用途径。方法以废瓦楞纸箱、办公废纸和废包装纸板作为原料,采用硫酸法降解制备纳米纤维素;利用所制备的纳米纤维素作为添加剂,加入过氧化氢氧化淀粉胶黏剂中,研究了不同原料、不同添加量的纳米纤维素对淀粉胶黏剂性能的影响。结果纳米纤维素的添加改良了氧化淀粉胶黏剂,当纳米纤维素的添加量为1%时,可以使氧化淀粉胶黏剂获得最优良的性能,此时黏度、干燥速度以及粘接强度均达到最大值,黏度为0.217 Pa·s,4 h时的失水率为43.43%,最大粘接强度为1.243 MPa,3种性能分别提升了5.8%,6.78%,17.26%。结论得到了不同原料制备的纳米纤维素对氧化淀粉胶黏剂性能的影响结果,为废弃纸包装的循环再利用找到了一种方法。     

合成条件对单组分水性聚氨酯胶粘剂性能的影响

研究了合成条件对单组分水性聚氨酯胶粘剂性能的影响,并对聚氨酯乳液做了红外分析.结果表明,内加交联剂A和B与水性聚氨酯乳液发生了交联反应,从而提高了水性聚氨酯胶粘剂的粘接强度,两者混合使用效果较佳.聚酯聚醚多元醇复配能提高水性聚氨酯的综合性能,当羧基含量为1.2%(质量分数)、NCO/OH比值(摩尔比)为1.3时,水性聚氨酯胶粘剂粘接性能较好.适量加入小分子扩链剂双酚A或丁二醇,可提高水性聚氨酯胶粘剂的硬度和粘接强度,降低其吸水率.     

导电胶的研究进展

目的 综述电子封装中用于代替锡铅焊料的导电胶的研究进展,对导电胶未来研究方向进行展望,为导电胶的应用提供参考。方法 从导电胶的组成、导电机理、类型入手,重点介绍导电胶应用时的关键性能要求与测试方法,并总结近几年在提高导电性、稳定性及降低固化温度、成本等方面的研究进展。结果 对导电胶中基体树脂进行改性并选择合适的导电填料(形状、组成),可改善导电胶的固化条件,并提高导电胶的导电性能、黏结性能、耐久性,满足苛刻应用环境下对器件连接高可靠性的要求。结论 相比传统铅锡焊料焊接的方式,导电胶具有绿色环保、连接温度低、分辨率高等特点。因此导电胶适用于电子封装与智能包装领域。目前导电胶的研究方向主要为提高导电性、黏结强度以及黏结稳定性。但是在面对固化时间长、耐湿热性弱、成本较高等缺点时,仍需不断优化组成,以满足实际应用要求。     

Investigation and assessment of epoxy resin adhesives using Fourier-transform infrared spectrometry

Epoxy resin adhesives are very attractive for many industries, especially in the aerospace and automotive industries because they eliminate heavy connection elements, such as bolts and screws, and reduce the total weight. This study assesses developed epoxy resin adhesives using Fourier-transform infrared spectrometry. The curing reaction between Epikote 828 epoxy resin and Epikure polyamidoamine curing agent 3090, and the chemical structure of the additives (CAB-O-SIL TS-720) used for rheology control and six different types of fillers (calcite with particle diameters of 700 nm, 5 μm, and 10 μm, coated calcite with a particle diameter of 900 nm, and barite and calcite with a particle diameter of 5 μm) employed in the adhesives are investigated. The Fourier-transform infrared spectrometry results of the epoxy resin and curing agent demonstrate that 83.5 % epoxy conversion is achieved at a temperature of 25 °C. The chemical composition of the additives with six different types of fillers and 1 %, 3 %, and 5 % additions of CAB-O-SIL TS-720 prepared in both nujol mull and potassium bromide discs is characterized using Fourier-transform infrared spectrometry. The potassium bromide discs yield higher intensities owing to good packing of cubic particles of potassium bromide with nano particle size CAB-O-SIL TS-720 and all filler types.     

碳酸钙填料对不饱和聚酯树脂体积收缩的影响及其机制

研究了CaCO₃填料对不饱和聚酯树脂（UP）体积收缩性能的影响,通过SEM、DSC、TG和溶胀实验研究了其作用机制。填料的加入导致填料/UP复合体系的体积收缩率先上升,后下降;用偶联剂对填料进行表面处理后加入复合体系中发现,复合体系的体积收缩率变小。填料主要通过以下3个方面影响复合体系的体积收缩：填料取代了部分树脂,有利于体系的体积收缩率下降;复合体系固化后在填料及UP界面处形成空隙,有利于复合体系体积收缩率的降低;填料抑制苯乙烯的挥发,导致体系中不饱和聚酯固化密度增大,使体系体积收缩率上升。偶联剂的加入增加了填料与树脂的界面作用力,且可使苯乙烯的挥发量增加,导致其交联密度下降,使体积收缩率下降。     

镀铝膜/PE膜复合用水性复合胶的开发与应用研究

用5种聚合物多元醇为原料,合成出一系列水性聚氨酯(PU)复合胶,探讨了水性PU复合胶对CPP镀铝膜、PET镀铝膜、PE等复合薄膜剥离强度的影响,同时还分析了硬段含量、固体含量、外加溶剂对剥离强度和干燥速度的影响.结果表明,用聚酯多元醇合成的水性PU复合胶对镀铝膜具有较好的粘接性能,28%硬段含量和40%固体含量水性PU复合胶,使镀铝膜具有较好的剥离强度和外观,添加少量醇溶剂能加速水性复合胶水分蒸发,满足工业化快速生产的要求.     

Effect of different copper fillers on the electrical resistivity of conductive adhesives

The effects of different copper fillers with different morphology and particle size have been studied in terms of electrical resistivity and thermal stability on the electrically conductive adhesives. The copper fillers used in this study were prepared by wet chemical reduction, electrolytic and gas atomization method, respectively. The as cured ECAs filled with different type of Cu fillers showed significant difference in electrical resistivity. Cu filler with smaller particle size showed higher packing density and larger surface area, which would enhance formation of conductive channels and increased conductive network in the ECAs, leading to a lower electrical resistivity. In addition, thermal stability of the ECAs were investigated under high temperature exposure at 125 °C and high humidity aging at 85 °C/85% RH for 1,000 h. Results showed that ECAs with Cu fillers of relatively small particle size and rough particle surface have excellent thermal stability due to enhanced adhesion and contact area between Cu fillers and the polymer matrix. A very low resistivity at an order of magnitude of 10^?4 ?? cm could be maintained for these ECAs after 1,000 h at 125 and 85 °C/85% RH.     

The effect of solder wetting on nonconductive adhesive (NCA) trapping in NCA applied flip-chip bonding

Flip-chip bonding using a nonconductive adhesive (NCA) and the effect of solder wetting on NCA trapping were studied. Three different solder materials with different melting point were used for the bonding process: In–48Sn, Bi–42Sn, and Sn–3.5Ag. Additionally, the bonding process was performed at various temperatures. We measured the amount of NCA trapping as functions of the solder material and bonding temperature. The fillers and NCA were easily trapped between the solder and Cu pads. The amount of trapped fillers and NCA increased with softer solder materials. These trapped fillers and NCA could be reduced if the solder melted and reacted to Cu pads during the bonding process. However, if the solder melted after fully curing NCA, the trapped NCA was not reduced due to the low mobility of cured NCA. Therefore, in order to reduce NCA trapping, the solder should be melted before curing NCA. The electrical test results showed that the contact resistance increased with increasing amount of trapped fillers and NCA.     

环氧树脂改性水性聚氨酯的合成研究

采用甲苯二异氰酸酯(TDI-80)、聚醚二醇(N220)、二羟甲基丙酸(DMPA)、环氧树脂和丙烯酸羟丙酯(HPA),合成了环氧改性的双键封端水性聚氨酯乳液.乳液由于含有不饱和双键而具有感光性能,故此乳液可用作水性紫外光固化涂料或胶粘剂的预聚物.实验结果表明,随着环氧树脂用量的增大,涂膜的硬度、耐水性、耐溶剂性及力学性能增强,但乳液外观和稳定性变差,故适宜的环氧树脂添加量为4%～8%.通过傅立叶变换红外光谱、粒径分析仪、凝胶渗透色谱(GPC)和透射电镜(TEM)等对乳液进行了表征.粒径分析仪分析显示,加入环氧树脂后,水性聚氨酯(WPU)分散体粒径增大,粒径分布变宽.凝胶渗透色谱分析表明环氧树脂改性水性聚氨酯提高了聚氨酯的分子量.     

A Review of Thermoplastic Composites Vapour Permeability Models: Applicability for Barrier Dispersion Coatings

One of the purposes of thermoplastic composites films and barrier dispersion coatings is to minimize the permeation of gases. In both cases, fillers and other additives are added during the film preparation to improve barrier properties. A high level of understanding has resulted from the study of the interaction between filler and polymer phases of thermoplastic composites, and a number of models have been developed to predict the relative permeability of these materials. However, barrier dispersion coatings have not been modelled in this way. The aim of this review was to discuss similarities and differences of thermoplastic composites and barrier dispersion coatings that may influence the applicability of the models for barrier dispersion coatings applied to paper‐based materials. The models were developed as a function of the amount of fillers added in thermoplastic composites films and geometrical characteristics of the fillers such as size, thickness, shape and the distribution of fillers in the film. Two‐ and three‐dimensional models with oriented and random arrangement of fillers were presented. Due to the parallel orientation and the similar length and width of fillers used in barrier dispersion coatings, three‐dimensional models were more suitable to predict relative permeability. These models assumed plate‐ or circular‐shaped fillers with parallel orientation. In order to prove the models, experimental information was required. Very limited data for barrier dispersion coatings with varying the amount of fillers have been reported in the literature. For this reason, further experiments are required under varied combinations of aspect ratio and the volume fraction of fillers. Copyright © 2015 John Wiley & Sons, Ltd.     

Effect of silver nanostructures on the resistivity of electrically conductive adhesives composed of silver flakes

Silver flakes are the most widely applied conductive fillers in electrically conductive adhesives (ECAs) because of their high conductivity and stable chemical properties. It is expected that there are advanced ECAs with both high electrical conductance and good adhesive strength. The high filler loadings can improve the conductance of ECAs, whereas the adhesive strength is decreased. Silver nanostructures are incorporated for the purpose of electrical conductance and adhesive strength improvement of ECAs. A simple method has enabled the synthesis of silver nanostructures by reducing silver nitrate with ethylene glycol in the presence of poly(N-vinylpyrrolidone). They are added to ECAs by dispersing them in ethanol while it is used as the diluent to adjust the volatility of ECAs, preventing them from the aggregation. This proposed process offers the possibility to effectively use silver nanostructures for improving the conductivity of ECAs at the low content of conductive fillers while good adhesive strength may be obtained.     

填料对阻尼隔声材料的水中插入损失的影响

本文研究了空心玻璃微珠、粉煤灰 (煤胞 )、发泡聚合物等填料对阻尼隔声橡胶材料水中插入损失的影响 ,发现橡胶中加入隔声填料可以明显提高水中插入损失。其中玻璃微珠插入损失最大 ,其次是粉煤灰 ,再次为发泡聚合物 ,而前三者等量混合物略差。玻璃微珠用量以 3 0份为宜 ,水中插入损失随用量增加而降低 ,在3kHz、1 0kHz、2 0kHz三个频段 ,用量 3 0份至 5 0份时 ,插入损失降低幅度较大 ,5 0份以后降低幅度变缓 ,其他频率也有类似情况     

水溶液聚合法制备高吸水树脂及NaCl对聚合反应的加速 …

采用ｉｎ－ｓｔｉｕ水溶液聚合法合成聚丙烯酸钠高吸水树脂,研究了引发剂用量、交联剂用量、反应温度和ＮａＣｌ用量对树脂吸水性能的影响,得出吸水率（Ｑ）与交联剂用量（Ｃｃ,交联剂相对单体的尔分率）之间存在Ｑ＝１．９９Ｃｃ＾－０．７６６关系。ＮａＣｌ对聚合反应具有加速作用,使反应时间大幅度缩短,但树脂的不率未受明显影响。     

Thermal and mechanical behaviour of flexible polyurethane foams modified with graphite and phosphorous fillers

Flexible polyurethane foams (FPF) are polymer materials that have high flammability. Fyrol PNX (FPNX) and expandable graphite (EG), have been used to modify the properties of these materials. The aim of this study was to assess the possibility of improving the thermal stability and flame retardancy of FPF by the addition of FPNX and EG fillers. The prepared foams were characterised by their apparent density, hardness, flexibility, irreversible strain and linear flammability, as well as thermogravimetric analysis (TGA), dynamic mechanical analysis, Fourier transform infrared spectroscopy (FT-IR) and pyrolysis combustion flow calorimetry (PCFC) measurements. The apparent density, hardness, flexibility and irreversible strain results showed that the addition of graphite and phosphorous fillers to the FPF makes slight changes to the mechanical properties, which remain within the acceptable norms. It was also observed that reducing the amount of Fyrol PNX and replacing it with the same amount of EG allowed similar values of linear flammability to be obtained with a simultaneous increase in thermal stability, as shown in the TGA study and the PCFC test. Moreover, it was found that the modification of flexible polyurethane foam by the addition of a mixture of FPNX and EG fillers allows the best properties of this type of materials to be obtained. This result indicates that this type of modification could be an effective way to improve the thermal stability of FPF.     

Evaluation of reinforced strength and remineralized potential of resins with nanocrystallites and silica modified filler surfaces

Surface-modified dicalcium phosphate anhydrous particles that were treated with an ion-rich solution and a silane-coupling agent were evaluated as fillers for resin composites. The physiochemical properties of these composites were characterized. The properties of the specimens as reinforcements, which were modified using various surface conditions and 30% and 50% filler to composite mass ratios (30% and 50%) were measured before and after they were immersed in water for 24 h. All groups were of the same strength and showed no significant changes after immersion. However, the groups showed a significant increase in the modulus after 24 h of immersion. The filler surfaces with nanocrystallites had the highest modulus, whereas the fillers treated with silanization had the lowest ion concentration in the solution and highest remineralization ability after immersion. The strength and brittleness were increased by the modified fillers with nanocrystallites on the surfaces and by the increased amount of fillers in the resin composites. Filler surfaces that were modified with silica hindered interfacial interactions and consequently had better flexibility and less brittleness during the light-curing process. Surface modifications of reinforced particles using nanocrystallites and silica films have superior potential applications in restorative medicine.     

混合多元醇对无溶剂聚氨酯覆膜胶性能的影响

以聚己二酸-1,4-丁二醇酯(PBA)、植物油多元醇、异弗尔酮二异氰酸酯(IPDI)和小分子多元醇为主要原料,制备了一种双组分无溶剂型聚氨酯胶粘剂。研究了双组分的配比R′和混合多元醇组分对聚氨酯胶粘剂固化速率、固化后胶膜的热稳定性和吸水率的影响,并测试了覆膜样品的T剥离强度。结果表明:当双组分配比R′=1.3时,胶粘剂综合性能最佳;添加小分子多元醇并不能提高胶粘剂的固化速率和耐热性,但能显著改善胶粘剂的粘结性能,并且选择性添加适量的小分子二醇,还能增强其耐水性。     

有机硅改性聚氨酯胶粘剂的研究

目的合成一种抗水性良好的无溶剂聚氨酯胶粘剂。方法采用聚酯多元醇(PBA)、异佛尔酮二异氰酸酯(IPDI)、蓖麻油和羟基硅油为原料,合成出一系列有机硅改性聚氨酯胶粘剂,并用红外光谱分析仪、热重分析仪对反应产物进行分析。同时考察不同羟基硅油的添加量对胶粘剂固化时间、固化膜吸水性、粘结性能等的影响。结果适量添加羟基硅油可以有效提高胶粘剂的粘接强度、耐热性和耐水性,但是羟基硅油添加量过多会延长预聚体的合成时间。结论羟基硅油添加的质量分数为3%～4%时最佳。