The Interlaminar Bond Strength of Flexible Polymer-Metal Laminates

An alternative test method to the traditional 180° “T” peel test has been developed for the measurement of interlaminar bonding in three-ply (polyester/aluminium/polypropylene) flexible-packaging, laminate materials. The new test is thought to involve mixed mode I (opening) and mode II (shearing) failure, and takes into account the yielding of the polypropylene layer during testing. The method allows more direct comparisons between materials to be made, and allows the measurement of strong bonds, where a peel test would result in yield or fracture of the substrate arms before debonding.     

Interlaminar Bond Strength and Failure Mechanisms in Commercial Flexible Polymer-Metal Laminates

An alternative to the 180° “T” peel test (called simply the “T-peel test” in the USA) was developed by Cropper and Young for the measurement of interlaminar bonding in three-ply polypropylene-aluminium-polyester laminates used in food packaging applications. The effect of temperature on the interlaminar bond strength of three laminate systems has since been studied. In particular, the effect of temperature on both the failure mode and on the adhesive's appearance after testing has been determined. It is shown that as the temperature is raised about 23°C, the laminating adhesive begins to soften and the failure mode changes from almost exclusively adhesive failure at the polyurethane adhesive-aluminium interface to cohesive failure of the polyurethane adhesive itself. The change in the failure mode is accompanied by the appearance of a meniscus instability. The temperature at which the meniscus instability patterns become more prominent correspond to the temperature at which the maximum interlaminar bond strength is attained.

It is thought that this new test can be used to characterise the behaviour of laminating adhesives more fully, both in their change in appearance with temperature, and in their effectiveness in bonding layers together as temperatures are increased above ambient conditions.     

Interlaminar Bond Strength and Failure Mechanisms in Commercial Flexible Polymer-Metal Laminates

An alternative to the 180° “T” peel test (called simply the “T-peel test” in the USA) was developed by Cropper and Young for the measurement of interlaminar bonding in three-ply polypropylene-aluminium-polyester laminates used in food packaging applications. The effect of temperature on the interlaminar bond strength of three laminate systems has since been studied. In particular, the effect of temperature on both the failure mode and on the adhesive's appearance after testing has been determined. It is shown that as the temperature is raised about 23°C, the laminating adhesive begins to soften and the failure mode changes from almost exclusively adhesive failure at the polyurethane adhesive-aluminium interface to cohesive failure of the polyurethane adhesive itself. The change in the failure mode is accompanied by the appearance of a meniscus instability. The temperature at which the meniscus instability patterns become more prominent correspond to the temperature at which the maximum interlaminar bond strength is attained.

It is thought that this new test can be used to characterise the behaviour of laminating adhesives more fully, both in their change in appearance with temperature, and in their effectiveness in bonding layers together as temperatures are increased above ambient conditions.     

Optimization of Surface Treatment and Adhesive Selection for Bond Durability in Ti-15-3 Laminates

The promising mechanical performance of a baseline Hybrid Titanium Composite Laminate (HTCL) inspired an investigation into maximizing the strength and environmental performance of this new aerospace material. This research focused upon finding the strongest and most durably combination of three commercially-available titanium surface treatments (i.e., Pasa-Jell 107^TM, Boeing's Sol-Gel, and Turco 5578^R) and two polyimide adhesives (i.e., LaRC^TM-IAX and FM5^R) for use in HTCL. The tests employed the cracked-lap shear (CLS) specimen geometry for fatigue crack growth measurements and also for fracture toughness analyses of the bonded specimens. The CLS geometry models several bonded applications found in the aerospace industry, and it also represents the debonding characteristics of a cracked titanium foil in HTCL.

The environmental performance of these six material combinations has been evaluated after 5,000 hours of continuous exposure to either a Hot/Wet environment that subjected the bonded specimens to 160°F (71°C) with relative humidity in excess of 95%, or to a Hot/Dry environment of 350°F (177°C) with a relative humidity of less than 5%. These two exposure environments utilized in this study are the most aggressive long-term environments that the HTCL is projected to experience while in service.

Test results showed that the best combination of the titanium surface treatments and the polyimide adhesives in the FM^R adhesive used in conjunction with Boeing's Sol-Gel titanium surface treatment. Though the FM5^R/Sol-Gel system was the strongest of all combinations, its performance dropped to less than 50% of its original strength after exposure to the Hot/Dry environment. An important finding is that this bonded system did not significantly degrade after exposure to the Hot/Wet environment. The only other material combination that showed substantial bond strength was the FM5^R/Pasa-Jell 107 system, though its strength also dropped to less than 50% of its original strength after exposure to the Hot/Dry environment.     

双组分黏合剂对聚脲层间黏结强度影响因素的研究

探讨了基材表面粗糙度、层间黏合剂养护龄期、环境温度和湿度对聚脲层间黏结强度的影响规律.实验结果表明：打磨处理后聚脲层间的黏结强度普遍提高;层间黏合剂养护龄期在2～4 h之间,黏结强度较高,在4.2～4.8 N/mmm范围内;随着环境温度的升高,黏结强度增大,高温下达到4.8 N/mm;环境湿度小时可获得较高的黏结强度.     

连续GF增强PP层合片材破坏形式及层间剪切强度研究

采用热压工艺制备连续玻璃纤维(GF)增强聚丙烯(PP)混编纱层合片材及GF呈0°和0°/90°铺放的连续GF增强PP层合片材。通过对3种GF增强PP层合片材进行力学性能测试,结果表明,3种GF增强PP层合片材的拉伸、弯曲强度随着层数的增加基本呈现先升高后降低的趋势。由于层合片材的层间剪切强度存在差异,因而使得3种层合片材产生不同的拉伸及弯曲破坏形式。通过插入PP薄层及PP-g-MAH薄层可改善层合片材的层间剪切性能,但插入PP薄层会降低层合片材的拉伸及弯曲性能,而插入PP-g-MAH薄层有助于提高层合片材的拉伸及弯曲性能。     

超高分子质量聚乙烯纤维黏结强度增强方法研究

为提高超高分子质量聚乙烯(UHMWPE)纤维复合材料中纤维与树脂基体之间的界面黏结强度,提出通过不同质量分数的硅烷偶联剂KH-570处理纳米SiO_2对UHMWPE纤维进行表面改性。对改性处理后的纤维与乙烯基酯树脂进行黏结强度试验,发现硅烷偶联剂处理纳米SiO_2能有效提高纤维的界面黏结强度,同时使纤维保持一定的断裂强度。     

Studies on Effective Bond Strength of Kendu Fruit Adhesive

Certain investigations on the effective bond strength of gum adhesive extracted from kendu (Diospyros cordifolia Roxb) fruit have been studied with respect to different interfaces such as general-purpose wood-wood, teakwood-teakwood, plywood-plywood, glass-glass, PMMA-wood, PVC-PVC. LDPE-LDPE, HDPE-HDPE, and PMMA-PMMA. The effects of different parameters such as curing temperature, curing time, thickness of specimens, and presolvent treatments on the bond strength of kendu fruit adhesive (KFA) are investigated. The bond strengths of KFA under different hazardous environments such as boiling water, saline water, and kerosene oil, acidic as well as alkaline solutions for the teakwood-teakwood interface have also been examined. A comparative account of studies of the effective bond strength of KFA with three different commercial synthetic adhesives such as Varnicol, Quickfx, and Araldite is reported. The KFA shows a superior bond strength for general-purpose wood-wood adhesion. Its bond strength is also comparable with synthetic adhesives for certain plastic-plastic as well as teakwood-teakwood adhesions. The retention of effective bond strength of KFA in various hazardous atmosphere remarkably encourages an industrial-grade adhesive formulation through proper R&D investigations. Adequate modifications and informations are required for an improved adhesive formulation from this natural adhesive to meet the industrial standard.     

Microtensile Bond Strength of Self-Adhesive Resin-Based Dental Cement to Bleached Enamel

This study investigated the effectiveness of bleaching agents on the micro tensile bond strength (µTBS) of self-adhesive luting cement and enamel. A total of 126 samples were prepared from the labial surfaces of permanent human maxillary central incisors and assigned into three groups with 42 samples each as: control, enamel bleached with 10% hydrogen peroxide (HP), and enamel bleached with 10% carbamide peroxide (CP). Rely X Unicem® (3 M, ESPE) was used as self-adhesive resin cement. The total testing period for bleaching was selected as 14 days and the bleaching agents were applied 8 hours a day. The statistical one-way ANOVA model and Tukey HSD multiple comparison test (α = .01) were used to assess the differences. The control group demonstrated the highest value (18.245 MPa) while HP and CP showed the much lower values of 11.150 and 14.222 MPa, respectively. Bleaching agents affect the µTBS negatively. Failure analysis of the fracture surfaces demonstrated that almost all samples showed adhesive failures at the cement-enamel interface.     

减缩剂改性新老混凝土修补界面层的细观结构与粘结强度

针对既有界面剂在新老混凝土修补中的缺点,以国产减缩剂对水泥砂浆界面剂进行改性,配制不同界面剂,分别对花岗岩石板和老砂浆界面进行修补,测试粘结强度,并观察细观结构。对比试验表明,减缩剂可有效改善界面层的宏观性能与细观结构,界面粘结强度显著提高。     

The Improvement of Bond Strength Properties and Surface Characteristics of Resinous Woods

Apitong (Dipterocarpus spp.) and Caribbean pine (Pinus caribaea Morelet) contain high amounts of extractives that contribute to poor bonding. To reduce, if not to eliminate, the effects of these extraneous substances, surfaces of small wood blocks were Soxhlet-extracted for 8 hours by different solvents. Wettability of the wood surfaces was then measured by droplet and dynamic methods using water and dilute NaOH as liquids. Tensile shear strengths of extracted wood bonded with aqueous vinyl polymer isocyanate (API), resorcinol formaldehyde (RF) and polyvinyl acetate (PVAc) resin adhesives were also measured. Results revealed that although Caribbean pine had much higher resin content than Apitong, the former had better wettability than the latter. Solvent extraction of the adherend with either hexane or ethanol-benzene (1:2) for 8 hours was not enough to improve its wettability but enough to improve its gluability. However, successive extraction with hexane, methanol and ethanol benzene rendered the wood satisfactorily wettable. Generally, a direct relationship between wettability and bond strength could not be observed. In a separate experiment to improve bonding strengths, test specimens were either overheated or autoclaved for 4 minutes at 125°C during the pressing period. Autoclave treatment was found to be useful in increasing the bond strengths of API, RF, PVAc and urea formaldehyde (UF)-bonded Apitong and Caribbean pine.     

覆铜箔层压板用新型铜箔胶粘剂配方的研究

本文制备了铜箔胶粘剂中所用的几种树脂,如封端和未封端的两种异氰酸酯预聚体,三种改性的三聚氰胺甲醛树脂和聚醚树脂。通过一系列研究确定了胶粘剂的理想配方,并通过红外光谱、热失重和差热分析法对其铜箔胶粘剂的反应过程和热稳定性进行了探讨.     

The Improvement of Bond Strength Properties and Surface Characteristics of Resinous Woods

Apitong (Dipterocarpus spp.) and Caribbean pine (Pinus caribaea Morelet) contain high amounts of extractives that contribute to poor bonding. To reduce, if not to eliminate, the effects of these extraneous substances, surfaces of small wood blocks were Soxhlet-extracted for 8 hours by different solvents. Wettability of the wood surfaces was then measured by droplet and dynamic methods using water and dilute NaOH as liquids. Tensile shear strengths of extracted wood bonded with aqueous vinyl polymer isocyanate (API), resorcinol formaldehyde (RF) and polyvinyl acetate (PVAc) resin adhesives were also measured. Results revealed that although Caribbean pine had much higher resin content than Apitong, the former had better wettability than the latter. Solvent extraction of the adherend with either hexane or ethanol-benzene (1:2) for 8 hours was not enough to improve its wettability but enough to improve its gluability. However, successive extraction with hexane, methanol and ethanol benzene rendered the wood satisfactorily wettable. Generally, a direct relationship between wettability and bond strength could not be observed. In a separate experiment to improve bonding strengths, test specimens were either overheated or autoclaved for 4 minutes at 125°C during the pressing period. Autoclave treatment was found to be useful in increasing the bond strengths of API, RF, PVAc and urea formaldehyde (UF)-bonded Apitong and Caribbean pine.     

Effect of Microwave Treatment on the Shear Bond Strength of Denture Tooth/Acrylic Resin

This study investigated the effect of microwave treatment on the shear bond strength of the denture tooth to acrylic resin adhesion, when the glossy ridge laps were unmodified, abraded, grooved, or etched by monomer. Eighty specimens (n = 10) were polymerized in a hot bath at 74°C for 9 hours, and deflasked after flask cooling. Specimens were soaked in 150 mL of distilled water and submitted to microwave treatment in a domestic microwave oven calibrated at 650 W for 3 minutes. Control specimens were not microwave treated. The shear bond strength test was performed in an Instron machine with a cross-speed of 1mm/minute. The ultimate fracture load value was transformed into shear bond strength as a function of the bonding area. Collected data were submitted to ANOVA and Tukey's test (α = .05). Treatment by microwave energy significantly decreased (p < .05%) the shear bond strength values in all ridge lap conditions used for the denture tooth/resin adhesion.     

连续GF增强PP层合板铺放成型工艺参数研究

以自制的连续玻璃纤维增强聚丙烯预浸带为原料,通过铺放成型工艺制备层合板材。采用正交试验,研究了铺放成型过程中4个主要工艺参数——压力辊压力、热风枪工作温度、压力辊内导热油温度、铺放平台底板温度对层合板材的层间剪切强度(ILSS)和空隙率的影响。结果表明,压力辊压力对层合板ILSS影响最大,对空隙率的影响次于热风枪工作温度;热风枪工作温度对空隙率影响最大,对ILSS的影响次于压力辊压力;其它两个工艺参数对ILSS和空隙率的影响均较小。在可操作的范围内,适当提高压力辊压力、热风枪工作温度和压力辊内导热油温度以及选择适中的铺放平台底板温度有利于降低板材的空隙率,提高板材的ILSS。在压力辊压力0.15 MPa、热风枪工作温度229℃、压力辊内导热油温度100℃、铺放平台底板温度95℃的最优工艺条件下,板材的ILSS达到21.54 MPa,空隙率为1.23%。     

Specific Interactions, Initial and Equilibrium Bond Strength in Polymer/Polymer Assemblies

This paper reports on bonding characteristics of assemblies using as substrates poly(vinyl chloride) (PVC), acrylonitrile-butadiene-styrene (ABS) and polypropylene (PP), and as melt adhesives an ethylene-vinyl acetate (EVA) copolymer, a polyurethane (PUr), and low density polyethylene (LDPE). Peel strength measurements on freshly assembled joints were compared with results for samples aged under inert and humid conditions. Significant time-dependent variations of bond strength were observed in all cases, but the direction of change varied among the assemblies. Those involving only dispersion-force materials displayed losses of bond strength, attributable to the gradual accumulation of cohesively weak layers at the substrate/adhesive interface. In assemblies involving materials able to interact by non-dispersion (acid/base) forces, as indicated by inverse gas chromatographic data, a variety of responses was obtained. These have been rationalized by the ability of the EVA and PUr adhesives to reorient when in contact with an appropriate polymer substrate. Reorientation, leading to bond strength increments, was associated with substrate/adhesive pairs (e.g., PVC/EVA and ABS/PUr), in which significant acid/base interaction could take place.     

芳纶纤维增强树脂基复合材料的界面粘结性能研究

为了改善芳纶纤维增强树脂基复合材料的界面粘结性能,从树脂基体入手,依据相似相容原理和芳纶的结构特点,合成出新型热固性树脂(AFR–T)用作芳纶复合材料的基体,以未经表面处理的芳纶作增强材料,采用热压成型法制备了AFR–T/芳纶纤维复合材料,并通过测定溶度参数、接触角、线膨胀系数、层间剪切强度(ILSS)和横向拉伸强度等方法研究了复合材料的界面粘结性能。结果表明,AFR–T树脂浇注体与芳纶的溶度参数相近,AFR–T树脂溶液在芳纶纸表面的接触角为36.9°,小于环氧树脂(EP)溶液与芳纶纸的接触角(53.2°),说明AFR–T树脂对芳纶的浸润性优于EP;AFR–T/芳纶纤维复合材料的ILSS和横向拉伸强度为73.0 MPa和25.3 MPa,分别比EP/芳纶纤维复合材料提高了25.9%和32.5%,这表明AFR–T树脂与芳纶纤维之间的浸润性和界面粘结性能较好。     

用X射线仪热分析仪研究影响磷酸氧化铜胶的粘接强度因素

用X射线粉末衍射仪和综合热分析仪对不同固化用具、不同固化温度的YW -Ⅰ磷酸氧化铜无机胶进行较系统分析、研究 ,找出了影响粘接强度的因素。     

NA—5聚氨酯胶粘剂对金属粘接强度的影响

以ＮＡ－５型氨酯胶粘剂作为金属五ＰＵ弹性胶料之间的胶粘剂，制作钢／ＰＵ橡胶／铝静件。研究了影响制件粘接强度的主要因素，给出了ＮＡ－５最佳粘接工艺。     

不同金属表面处理对高分子材料与金属连接强度影响

分别利用喷砂、氢氧化钠阳极氧化和激光毛化3种方法对钛合金板进行了表面处理,通过提高其表面粗糙度,来达到提高相应金属–高分子连接件连接强度的目的。其中激光毛化处理能有效提高相应连接件的拉伸性能,而氢氧化钠阳极氧化处理可以有效提高连接件的剥离强度。综合这两种处理方法所制备的金属–高分子连接件的连接强度得到明显提高,拉伸强度为322 MPa,断裂伸长率为5.1%,剥离强度为4.70 N/cm。