Peel Strength Tests Research Articles

Rapid treatment of polyimide film surfaces using high-density microwave plasma for enhancement of Cu layer adhesion

A high-density microwave plasma has been applied to the surface of polyimide (PI) films as a treatment to enhance the adhesion of sputter-deposited copper layers. A very short (∼5 s) exposure to Ar plasma enhanced the contact angle from 72° to ∼14°. X-ray photoelectron spectroscopy and atomic force microprobe measurements showed an increase in hydrophilic radicals (–OH, –C O) and surface roughness, respectively, following the plasma treatment. Peel strength tests of Cu layers deposited on plasma-treated polyimide films showed that the plasma treatment significantly enhanced Cu layer adhesion.

The durability of epoxy resin coating

The durability of epoxy resin coating was studied under environments with relative humidity (RH) of 98%–100%, at 55 °C for 900 h, at 65 °C for 700 h and at 75 °C for 400 h, respectively. Peel strength test, dynamical mechanical thermal analysis (DMTA), infrared spectroscopy (IR) and energy dispersive X-ray spectroscopy (EDX) were employed for measurements. Peel strength indicated the development of adhesive property of the coating, DMTA indicated the development of physical property, IR revealed the development of chemical structure, and EDX showed surface element change of the coating. All these results show a good timetemperature equivalence characteristic between humidity aging time and temperature.

Application of a Chemically Adsorbed Monolayer and Polypyrrole Thin Film for Increasing the Adhesion Force between the Resin Substrate and the Plated Copper Layer

AbstractA chemically adsorbed monolayer containing pyrrolyl group (Pyrrolyl-CAM) was prepared between a plated copper layer and a resin substrate for increasing the adhesion force without roughening a surface of the resin substrate. Although it was not enough to increase the adhesion force between the resin substrate and the copper layer by using only Pyrrolyl-CAM, the sufficient adhesion force was obtained by preparing a polypyrrole thin film between Pyrrolyl-CAM and the copper layer.Pyrrolyl-CAM and the polypyrrole thin film on the substrate were evaluated by an automat-ic contact angle meter and auger electron spectroscopy in order to analyze the condition of the films between the resin substrate and the copper layer.The peel strength test was carried out in order to evaluate the adhesion force. The best ad-hesion force was 0.98 [N/mm], and the target value of 0.60 [N/mm] was sufficiently achieved.

Effects of ultraviolet irradiation treatment on the surface properties and adhesion of moso bamboo (Phyllostachys pubescens)

The poor adhesion of bamboo coatings is a serious issue in the bamboo industry. To overcome this problem it is necessary to modify the actual surface of the bamboo before finishing. A study on the surface properties and adhesion of moso bamboo (Phyllostachys pubescens) were investigated with various UV irradiation conditions including irradiation time and dose using different UV lamps. Two types of wood coatings, i.e., solvent-borne nitrocellulose (NC) lacquer and waterborne polyurethane (PU) coating, were used in the study, and 180° peel strength and shear strength tests for measuring adhesion of films were conducted. The results revealed that the wettability and the carbonyl group concentration of the bamboo surface were increased. This was particularly apparent for an irradiation time less than 15 s with a mercury UV lamp (H-lamp), rated at an intensity of 100 W/cm kept at a distance of 15 cm. In all the treatments, the greenish appearance of moso bamboo was retained and the adhesion was improved. Especially, using solvent-borne NC lacquer finishing, the higher-dose (under a mercury UV lamp combined with metal halide lamp; H + M-lamps) irradiated bamboo had the best adhesion, while, for waterborne PU coating, the H-lamp irradiated one showed the best improvement. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Adhesion Modeling on Rough Low Linear Density Polyethylene

Food adhesion is an important attribute that could have both positive and negative ramifications depending on the application. Yet, its quantification remains cumbersome and as a consequence adhesion models are scarce. The effect of surface roughness, free energy, and ozone treatment on adhesion of rough low linear density polyethylene films was investigated. Adhesion was measured by a 180 degrees peel strength test. The plastic films were roughened (surface roughness ratio, r, ranged from 1.00 to 1.15). Exposing the film to ozone treatment (0 to 300 s) modified its surface free energy, gamma(s) (32.4 to 37.9 mJ/m(2), respectively), and its polar component of the surface free energy, gamma(p)(s) (3.0 to 8.3 mJ/m(2), respectively). The films were coated with polyurethane capable of forming hydrogen bonds. Adhesion was found to be a function of the apparent contact angle of water, theta(ap[water]), surface roughness ratio, and surface free energy. The linear relationship between the apparent contact angle of water, theta(ap[water]), and gamma(p)(s) was incorporated in building an empirical model that quantifies peel strength as function of r and gamma(p)(s). The model showed good agreement with experimental data, especially for longer ozone exposures and rougher surfaces. The empirical model provides insight into the relationships between surface roughness, surface energy, and adhesion. Quantifying these effects could facilitate reducing biofilm forming on food equipment, antisticking treatments, or easy peel packages, or reducing food residues adhering to the food packages and consequently minimize oxidation, off flavors, and waste.

Effect of Heat Sealing Temperature on Mechanical Properties and Molecular Structure of Heat-sealed Polylactic Acid Film

Heat sealing is currently a standard method for manufacturing plastic bags of polylactic acid film, which has high clarity and strength. However, the heat sealing of polylactic acid is difficult because its strength declines at high temperatures. Processing conditions such as the heat sealing temperature and pressure can greatly affect the mechanical properties of the heat sealed part. In this study, the relationship between the heat sealing temperature and the mechanical properties of heat-sealed polylactic acid film were examined through peel strength tests and tensile testing of samples with circular notches. Differential scanning calorimetry (DSC) and FT-IR imaging were used to investigate the dependence of crystallinity and molecular-orientation ratio (MOR) on the heat sealing temperature. These studies showed that the optimum heat seal temperature was 128°C, with a very narrow temperature window. Thus, precise control of the heat sealing temperature is required for polylactic acid plastic bag manufacture.

Effects of hydrogen peroxide treatment on the surface properties and adhesion of ma bamboo (Dendrocalamus latiflorus)

The poor adhesion of bamboo coatings is a serious issue in the bamboo industry. To develop a pretreatment method that improves the adhesion of films and increases the economic value of bamboo products, a study of hydrogen peroxide treatment with solutions of various pH (pH 4–9) on bamboo surfaces was conducted. Five-year-old ma bamboo (Dendrocalamus latiflorus Munro), and nitrocellulose lacquer were used in the study. Surface properties of the bamboo such as contact angle and color were evaluated, and 180° peel strength and shear strength tests for measuring adhesion of films were conducted. The results showed that the wettability of water droplets and the carbonyl group concentration on the bamboo surface were increased significantly by alkaline (pH 8 and 9) hydrogen peroxide treatments. There was only minor color variation and the outer wax layer of bamboo was etched to form additional recesses after hydrogen peroxide treatment. It was also found that all hydrogen peroxide treatments improved the adhesion of bamboo coating; bamboo treated with hydrogen peroxide at pH 7 showed the greatest improvement. The enhanced adhesion was attributed to the mechanical interlocking of the film on the treated bamboo rather than to surface activation.

Hydrophilic interpenetrating polymer networks of poly(dimethyl siloxane) (PDMS) as biomaterial for cochlear implants

Poly(dimethyl siloxane) (PDMS) was bulk-modified to develop a new intra-cochlear electrode that can closely hug the inner wall of scala tympani (ST). The hydrophilicity of bulk and surface of PDMS was changed using a sequential method for preparation of interpenetrating polymer networks (IPNs). A series of IPNs, based on PDMS and poly(acrylic acid) (PAAc), was synthesized and characterized by means of attenuated total reflectance Fourier transform infrared spectroscopy, water contact-angle measurement, dynamic mechanical thermal analysis and peel strength tests. The performances of actual-sized fabricated electrodes were assessed inside a transparent model of ST, which was filled with saline. The cell behavior of L929 fibroblasts on materials was studied in vitro.

Surface modification of polyester to produce a bacterial cellulose-based vascular prosthetic device

The surface of medical grade polyesters was modified to impart hydrophilic character for attachment to bacterial synthesized cellulose to produce a vascular prosthetic device. The polyesters were treated with UV/ozone, air plasma, and nitrogen plasma for various lengths of time. The unmodified and modified surfaces were analyzed by X-ray photoelectron spectroscopy (XPS) and advancing contact angle measurements. The surfaces were then coated with bacterial produced cellulose to study adhesion properties through tensile testing (peel testing). UV/ozone and plasma treatment XPS results indicated an increase in the oxygen concentration in the form of C O(H) on the treated polyester surfaces. The treatment time to reach steady state in the case of air and nitrogen plasmas took the order of seconds, while 7 min and longer were required for UV/ozone treatment. Peel strength tests to measure adhesion of modified polyester to cellulose reached their maximum values when the C O(H) concentrations were at the highest level. It was also at this level that the contact angle measurements showed no further decrease.

Characterisation of heat-sealing part of laminated oriented nylon and polyethylene films

In order to clarify the relationship between heat-sealing conditions and the strength of the heat-sealed part, the crystalline structure of the heat-sealed part of the film was evaluated by differential scanning calorimetry (DSC) and Fourier transform infrared (FT IR) spectroscopy. The laminated films that include a biaxially oriented nylon (ONY) film and a cast linear low-density polyethylene (LLDPE) film with an appropriate adhesive were heat-sealed by using an impulse type heat-sealer. First the possibility of adhesion was examined by changing the processing conditions and the maximum temperature was measured. As for mechanical properties, a peel strength test was performed to evaluate the strength of the heat-sealed parts. However, the strength could not be evaluated by the peeling test alone, because the fracture shifted from the heat-sealed part to the edge of the heat seal accompanied by necking and yielding of the film. In order to solve this problem, a tensile specimen with a semicircular notch was proposed to evaluate the strength of the heat-sealed part. Tensile strength increased with increasing crystallinity of the LLDPE indicated by the melting peak in the DSC measurement and FT IR spectra. It was found that crystallinity profoundly affected the mechanical properties of the heat-sealed part.

The influence of surface treatment and luting cement on in vitro behavior of two-unit cantilever resin-bonded bridges

The purpose of this study was to find the optimal combination of surface pretreatment and luting cement for two-unit CoCr cantilever resin-bonded bridges. Tensile peel, load and torque strength tests were performed using flat ground bovine teeth as substrate, four different commercially available luting cements, and CoCr beams as simulated cantilever resin-bonded bridges. The CoCr beams were pretreated with sandblasting or Rocatec. Tensile peel, load and torque strengths were determined 72h after cementation. The effects of sandblasting and Rocatec pretreatments on the morphology of the CoCr surface was investigated with SEM and EDAX analysis. The average strengths of the three tests showed that Rely X ARC, Resiment and Panavia were the same and significantly lower than UniFix. Rocatec showed a significantly higher average bond strength than sandblasting considering all tests. The peel test, which showed the lowest failure values, is clinically the most relevant test. This test showed that only UniFix as luting cement with sandblasting as pretreatment generates a significantly higher bond strength compared with the other cements and pretreatments. Based on the results of this study the use of Unifix with sandblasting as metal surface pretreatment, is preferred for cementation of two-unit CoCr cantilever resin-bonded bridges.

低温プラズマを利用したＰＶＡ‐ヨード偏光フィルムの加湿耐久性の改善

The effect of low temperature O2 plasma on the adhesive ability and optical durability for polarized PVA film has been investigate. Low temperature O2 plasma treatment modified the PVA film with physically and chemically. The surface of PVA film was modified by O2 plasma treatment and analyzed using ESCA, peel strength test and AFM image. The adhesive strength of all plasma treated PVA films was stronger than those of untreated one. Especially, the AFM image of the O2 plasma treated PVA film showed the maximum peak after 7min. under 100 and 150W output power. The adhesive strength of the O2 plasma treated PVA films also showed the maximum peel strength. These results suggested that the O2 plasma had the advantage of adhesive ability improvement of PVA film. We obtained that O2 plasma treated PVA iodine polarized film shows better durability in the experimental condition.

Study of bond strengths of a water-borne polyurethane (PU) adhesive for shoe-soling materials

The feasibility of the use of water-borne adhesives in shoe manufacture was demonstrated about 10–15 years ago but their use is still limited to a few shoe manufacturers in the developed countries. This study reinforces the effectiveness of water-borne adhesives for sole bonds. The peel strength test is carried out using different types of upper and soling materials. In all cases, a water-borne polyurethane (PU) adhesive is used and the results obtained indicate that the bond strengths are adequate for everyday footwear. The application method and equipment are also found to be almost identical to that of a traditional solvent-borne adhesive. Thus the use of water-borne adhesive may be an alternative approach for sole bonds and this can also eliminate the potential hazards associated with organic solvents.

Adhesion of an aromatic thermosetting copolyester with copper foils

AbstractCopper foils have been widely used in microelectronic devices. Adequate adhesion between copper foils to various substrates, such as Si, SiO2, polyimide, is crucial to high performance of these devices. The adhesion between a new high temperature adhesive, aromatic thermosetting copolyester (ATSP), and various copper foils, namely, zinc(Zn)‐coated copper foil, copper foil and nickel (Ni)‐coated copper foil was characterized by a 90° peel strength test. It was found that the peel strength of Zn‐coated copper foil to ATSP was 1050 N/m, which was more than three times higher than copper foil and five times that of Ni‐coated copper foil. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and X‐ray photoelectron spectroscopy (XPS) studies indicated that this higher adhesion results from the stronger mechanical interlocking due to the rougher surface of Zn‐coated copper foil, and from chemical reactions at the interface which occur during the curing process of ATSP on the Zn‐coated copper surface. In contract to the adhesive failure at the ATSP/Cu and ATSP/Ni interfaces, the failure mechanism of ATSP/Zn is both cohesive and adhesive. Copyright © 2004 John Wiley & Sons, Ltd.

Segmented detachable structure of cochlear-implant electrodes for close-hugging engagement with the modiolus.

Surface and bulk modification techniques of polydimethylsiloxane (PDMS) polymers were used to develop a new intracochlear electrode that can closely hug the inner wall of scala tympani. Laser-induced surface grafting of poly (2-hydroxyethyl methacrylate) (PHEMA) and sequential method for preparation of interpenetrating polymer networks (IPNs) of PDMS/PHEMA were, respectively, used for surface and bulk modifications. The hydrogel content and water-uptake capability of the modified samples were optimized by Taguchi method for experimental design. The modified PDMS samples were examined by performing attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, water contact-angle measurement, and peel strength tests. The performances of actual-sized fabricated electrodes were assessed inside a transparent model of scala tympani, which was filled with saline. After a swelling process, the hydrophilic branch begins to elongate and detach from hydrophobic branch and pushes it toward the inner wall.

Adhesion between modified and unmodified poly(dimethylsiloxane) layers for a biomedical application

Surface and bulk modification techniques of poly(dimethylsiloxane) (PDMS) polymers were used to develop a new intra-cochlear electrode for close hugging of inner wall of scala tympani. Laser-induced surface grafting of poly(2-hydroxyethyl methacrylate) (PHEMA) and sequential method for preparation of interpenetrating polymer networks of PDMS/PHEMA were, respectively, used for surface and bulk modifications. The modified PDMS samples were studied by performing attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, contact angle measurement, and peel strength tests. The role of adhesion between modified and unmodified PDMS layers on the performances of two-layer structures was studied with peel strength test. The actual-sized fabricated electrodes were assessed inside a transparent model of scala tympani that was filled with saline.

Air channel testing of thermally bonded PVC geomembrane seams

Polyvinyl chloride (PVC) possesses excellent thermal welding characteristics, such as a wide thermal seaming range and the absence of a need for surface preparation such as grinding. The focus of this study was to utilise these welding characteristics to develop a procedure for air channel testing of dual track thermal seams and recommend that destructive testing of PVC geomembranes be reduced and possibly discontinued. This is possible because of the development of a relationship between thermally welded seam burst strength and seam peel strength for a given sheet temperature. To develop this relationship, test welds were created using hot air and wedge welders at two different geomembrane temperatures, two different geomembrane thicknesses, three welding speeds, and three welding temperatures. The 72 seams created were evaluated by conducting ASTM D 6392 peel strength tests at room temperature (22.8°C) and a burst test developed herein at three different sheet temperatures. This paper presents the test results, which illustrate the importance of welding temperature and speed. The test results are also used to develop a relationship between seam peel strength and burst pressure, which can then be used to conduct field burst tests to ensure the specified seam peel strength(s) are satisfied along the entire seam length instead of over the limited seam length used in destructive tests.

Air channel testing of thermally bonded PVC geomembrane seams

Polyvinyl chloride (PVC) possesses excellent thermal welding characteristics, such as a wide thermal seaming range and the absence of a need for surface preparation such as grinding. The focus of this study was to utilise these welding characteristics to develop a procedure for air channel testing of dual track thermal seams and recommend that destructive testing of PVC geomembranes be reduced and possibly discontinued. This is possible because of the development of a relationship between thermally welded seam burst strength and seam peel strength for a given sheet temperature. To develop this relationship, test welds were created using hot air and wedge welders at two different geomembrane temperatures, two different geomembrane thicknesses, three welding speeds, and three welding temperatures. The 72 seams created were evaluated by conducting ASTM D 6392 peel strength tests at room temperature (22.8°C) and a burst test developed herein at three different sheet temperatures. This paper presents the test results, which illustrate the importance of welding temperature and speed. The test results are also used to develop a relationship between seam peel strength and burst pressure, which can then be used to conduct field burst tests to ensure the specified seam peel strength(s) are satisfied along the entire seam length instead of over the limited seam length used in destructive tests.

The effect of sputtered interface metallic layers on reinforced core laminate making build-up structures

In conventional printed circuit board manufacturing, pressure and heat are used to attach the copper layer to the laminate. To achieve narrow lines the additive method is used instead. To produce the seed metal, a palladium bath is quite often used. This method is used in conventional PCB production. In our paper we suggest a new method of arriving at a very thin and even surface by sputtering. The sputtering process is done in a simple chamber with an argon atmosphere. The process is rapid (only few tens of seconds) and inexpensive, since the produced layer is very thin. This sputtered metal acts as an adhesion layer, and copper can be grown on this layer either through electrolysis or by electroless means. In the adhesion test, the sputtered and copper-coated specimens were subjected to a peel strength test. It has been noted that the adhesion of sputtered metal to the epoxies differs greatly depending on the metal used. The effects of heating after sputtering have also been identified. It has also been noted that the treatment of the surface has a significant effect on adhesion. In this paper we describe the sputtering method, the results of the peel strength tests and the treatments, which act on the adhesion of the metal to the base laminates.

Application of medium frequency atmospheric plasma on continuous aluminum wire cleaning for magnet wire manufacturing

Recently, the study on the application of atmospheric plasma treatment has gradually increased because it requires high cost vacuum systems, and the flexibility of application to a continuous process. This paper reports on the new application of medium frequency atmospheric plasma to the continuous surface cleaning of aluminum wire for magnet wire manufacturing. Magnet wire is widely used for transformers and motors. It is composed of a metallic conductor of copper or aluminum, and various types of enamel coated layers as insulator. Copper has been mainly used as a conductor of magnet wire. The use of aluminum conductor has gradually increased, replacing the copper and thus, reducing the wire weight. In order to be used as a conductor of magnet wire, the copper or aluminum wire should be drawn to a proper size. After that, the drawn wire is coated with enamel varnish, and is finally annealed at a temperature of approximately 400°C. In this process, in order to obtain enough bonding strength between conductor and enamel, the drawn wire should have a clean surface without lubrication oil residuals from the wire drawing process. As the lubrication oil for aluminum wire drawing is highly viscous and insoluble in water, tri-chloroethane (1,1,1-TCE), one of the most powerful cleaning agents has been most widely used. However, the manufacture and use of 1,1,1-TCE is restricted by law due to its environmental impact on the ozone layer. This study was performed to solve the environmental problems of conventional chemical cleaning agents such as 1,1,1-TCE by applying a medium frequency atmospheric plasma treatment. Medium frequency and high voltage power supplier (20 kHz, 7∼1.5 kV) was used as a plasma power source, and a tube type electrode was prepared for continuous wire cleaning process. For the evaluation of cleaning effect, not only naked eye inspection, but also surface tension test and peel strength tests were performed. The results were quite good. The wire, which was exposed to corona discharge in the tubular electrode for 0.3–1.2 s, had better surface cleanness than that of wires treated with 1,1,1-TCE. This cleaning effect comes from the reactive oxygen ions generated in the plasma.