Peel Force Research Articles

Investigation of the vibration assistance on the bark peeling tool to reduce the force required for cinnamon (<em>Cinnamomum zeylanicum</em>) peeling

Cinnamon (Cinnamomum zeylanicum) is the predominant spice among other export crops in Sri Lanka. The bark peeling process of cinnamon requires high skilled labour and the force required is subordinate only to the bark rubbing step. Since the traditional tools used for peeling are inefficient, a study was conducted to explore possibilities of using a vibration-assisted peeling knife to reduce the required force for cinnamon peeling and to enhance productivity. Three types of eccentric rotating mass motors (RF-555, R260 and MABUCHI RF-M50WA) were fixed to induce mechanical vibrations to the peeling knife. Vibration generated from the selected motors was changed by means of frequency and acceleration through the supply voltage, and respective values were recorded by an accelerometer. Selected cinnamon sticks (diameter 3.5 cm and length 10 cm) were tested by peeling out of 5 mm width bark strip from the stick at each frequency – acceleration rate values. As a control test, sticks with similar diameter and length were peeled without the vibration assistance. The motor RF555- ERM, offered the highest advantage for the peeling force reduction (73.22% - 78.6%) when compared to the control test. The results showed that the potential of using ERM in vibration-assisted tools to reduce the bark peeling forces of cinnamon sticks.

Effect of the Crosslinking Agent Content on the Emulsion Polymerization Process and Adhesive Properties of Poly(N-Butyl Acrylate-Co-Methacrylic Acid)

A series of poly(n-butyl acrylate-co-methacrylic acid) with different contents of acrylic crosslinking agent (1,4-butanediol dimethacrylate, BDDA) latexes, named as poly(BA-co-MAA-co-BDDA), PBMABD, were synthesized via a two-stage sequential emulsion polymerization. During the polymerization, the particle sizes of the PBMABD latexes and conversions including instantaneous conversion and overall conversion of monomers were monitored online by dynamic light scattering (DLS) technology and gravimetric analysis in half-hour intervals, respectively. The overall conversions at the end of emulsion polymerization with different crosslinking agent contents were high, and the latex particles grew in a spherical shape without secondary particles during the growth process. The adhesive properties, including loop tack force, peel force and shear resistance, were evaluated systematically according to Fédération Internationale des Fabricants et Transformateurs d'Adhésifs et Thermocollants sur Papiers et Autres Supports (FINAT) test methods. When the content of the crosslinking agent was 0.5 wt%, a best equilibrium among the adhesive properties could be achieved. The adhesive properties of the PBMABD polymer were closely related to its viscoelastic behaviour and molecular structure, such as gel content and various molecular weight parameters.

Mechanical properties and microstructure evolution of dissimilar Mg and Al alloys welded using ultrasonic spot welding

Magnesium and aluminum alloys are used in the development of lightweight materials for the automobile industry. Ultrasonic metal welding is a solid-state bonding technology widely used in lightweight metal welding that has unique advantages for welding dissimilar Mg-Al alloys. In this work, the mechanical properties and interfacial reaction behavior of ultrasonically spot-welded joints of dissimilar Mg-Al alloys were studied using a universal tensile testing machine, scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). The results showed that the joint strength first increased and then decreased as the welding energy increased. At a welding energy of 980 J, the maximum peeling force of the joint was 0.107 kN, and the failure mode of the weld occurred via a ‘local Al alloy nugget pull-out’. At a welding energy of 1540 J, a continuous ∼20 μm thick intermetallic compound (IMC) layer composed of Al12Mg17 and Al3Mg2 phases formed at the welding interface, which deteriorated the mechanical properties of the joint. As the interfacial temperature increased along with the welding energy, mixed particles formed, and element diffusion accelerated at the interface, which promoted growth of the IMC layer. Dynamic recrystallization occurred near the weld interface under shear deformation as well as deformation heating, which refined the grain size and changed the texture.

Enhanced Directional Adhesion Behavior of Mushroom-Shaped Microline Arrays

We report directional switchable adhesion behavior inspired by the locomotion mechanism of gecko lizard. The robust mushroom-like polydimethylsiloxane microline arrays are fabricated by using silicon based over-etching process and replica molding. The line gecko patterns attached to the glass substrate exhibit strong shear adhesion forces in parallel and perpendicular directions with respect to the line direction and high adhesion hysteresis property only in the parallel direction. We have explained the directional adhesion behavior of the line gecko pattern by comparing peeling propagation and normal adhesion phenomenon. Then, we have successfully demonstrated silicon wafer transportation with the line gecko pattern by using directional adhesion behavior of the pattern, which is high shear adhesion force and low peeling force in the parallel direction with respect to the line direction.

Swelling effects on localized adhesion of an elastic ribbon.

We investigate the adhesion mechanism between an elastic strip of vinylpolysiloxane bent in a racquet-like shape, and a thick elastomeric substrate with the aim to understand how local swelling modifies adhesion. Using a modified loop-tack adhesion test, we place a droplet of silicone oil in between the two materials, vary the dwell time and measure the force required to separate the two interfaces. The experiments are then compared with an analytical model that describes how the critical peel force is modified as the interfacial surface energy changes over time. Our study reveals that in certain circumstances swelling can enhance adhesion. More specifically, strong adhesion is obtained when most of the droplet is absorbed by the solid. By contrast, when the droplet remains at the interface a small adhesive force is measured.

Adhesion Strength and Rolling Properties of Descemet Membrane Endothelial Keratoplasty Grafts in a Rabbit Eye Model

ABSTRACT Purpose To investigate the optimal time for Descemet membrane endothelial keratoplasty (DMEK) graft peeling, and to analyze the rolling properties of endothelial denuded grafts in a rabbit eye model. Materials and Methods The vertical peeling force required to peel 1 mm wide Descemet membrane (DM) strips, was measured as the change in weight of the system during force application in a rabbit model. Twenty-one rabbit corneoscleral rims were stored in phosphate-buffered saline (PBS) at 4°C, and force analysis was performed at days 1, 5, or 21 after harvesting. After half of the strips of day 5 corneas were peeled and analyzed, the rims were moved to Optisol GS at 4°C, and the remaining strips were peeled off for force analysis at day 10. Separate DM grafts (n = 7) were analyzed by intraoperative optical coherence tomography (OCT) to determine the tissue rolling diameter before and after removal of endothelial cells by a swab. Unpaired t-test was used for statistical analysis. Results There was a decrease in DM peeling force (p = .008) between days 1 and 5 (556.04 ± 111.76 and 324.30 ± 96.4 mg, respectively), and no difference between days 5 and 21 (p = .53). Peeling force for day 5 corneas placed in Optisol was higher at day 10 (324.30 ± 96.4 to 669.92 ± 166.24 mg, p = .005). The average rolling diameter of DM grafts was similar before and after the removal of endothelial cells (257.9 ± 131.1 and 249.8 ± 126.6 μm, respectively). Conclusions DMEK Graft procurement could be potentially facilitated by lower DM-stromal adhesion strength at day five after obtaining corneoscleral rims, in a rabbit eye model. Time in the storage medium may influence adhesion strength. Endothelial cells do not appear to play a significant role in the rolling diameter of DM grafts.

Evaluation of coating rate and adhesive force for copper deposition on the surface of polypropylene

In spite of the metal-coated nonconductive materials have been widely used in many purposes, the coating rate and adhesive force of a metal to nonconductive material need to be evaluated. This study aims to investigate the effects of NaOH, CuSO4, HCHO and immersion time on coating rate and adhesive strength of CuO coatings on the polypropylene surface. The results showed that the coating rate of CuO deposition strongly affected by NaOH but weakly affected by CuSO4 in electroless solution. The addition of HCHO from 0.0136 to 0.0642 M in electroless solution can lead to the increased coating rate from 3.84 to 41.82 m/h; however, the increase of coating rate is almost constant when the concentration of HCHO reaches more than 0.0642 M. The increase of either CuSO4 concentration or immersion time leads to an increased peeling force of CuO coated on the surface of polypropylene. An optimum adhesive thickness on the bond strength of CuO with the surface of polypropylene can be obtained when the polypropylene sample was immersed in the electroless solution containing 0.0187 M CuSO4 for 34.10 min. The research findings contribute to advance understanding of many variables affected adhesion strength between CuO and polypropylene.

Enhanced thermal and mechanical properties of natural silkworm cocoon composites constructed by multi-silkworm larvae simultaneously

In this study, we developed a simple route to fabricate natural silkworm cocoon composites with dense fiber networks and low porosities. The thermal and mechanical properties of these modified cocoons are significantly improved. Especially, the tensile strength, elongation, toughness and the average peeling force of the cocoon constructed by three silkworm larvae simultaneously are found to be 1.7, 1.5, 2.1 and 2.1 times higher than those of the normal cocoon, respectively. These special cocoons with good mechanical properties could be applied to produce high-performance artificial cocoon composites, biomimetic and ballistic materials.

Experimental study on peeling performance of T-type brazing joints

As a promising heat transfer component of high temperature gas cooled reactor (HTGR), the performance of the plate-fin heat exchanger determines the energy efficiency and life of the HTGR. Although the plate-fin structure has lots of advantages such as high efficiency, compact structure, low manufacturing cost, its performance is greatly affected by the vacuum brazing technology and harsh conditions, e.g. high temperature and high pressure. In the practical application, “peeling” failures may occur in the brazing joint between the fin and the parting sheet. It becomes necessary to characterize the strength of the joints. However, the standard specimen cannot accurately describe the real stress distribution. In the present study, a T-type specimen is designed for the peel test of brazing joints. To reflect the influence of brazing seams and thickness of the base metal, five specimens are designed and tested under 25 °C, 450 °C, 550 °C and 650 °C with five different applied loads, respectively. Based on the bilinear hardening model, the peeling performance of all T-type joints are obtained according to the tested peeling force-displacement curves. Then the influences of base metal thickness, brazing seam, loading rate and test temperature on the peeling performance are analyzed. The results show that the maximum peel force, the average peeling force and the fracture energy all decrease as the results of increased base metal thickness. With the increase of the filler thickness, the average peeling force and the fracture energy of the brazing joints both decrease. The joints with 0.95 mm base metal thickness and two layers of brazing filler metal are recommended for the peeling test of the T-type specimen. The loading rate of the peel test has no significant effect on the average peeling force and the fracture energy.

Peeling mechanics of hyperelastic beams: Bending effect

In this work, a new adhesion model is proposed to analyze the peeling behavior of hyperelastic beams from a rigid flat substrate by utilizing a recently developed finite strain Euler beam model and the concept of adhesion energy. Both the large strain effect and bending effect are taken into account in the model. Hence, the model can be seen as a generalization of the extensible elastica-type adhesion model to the finite strain case, and it can also be taken as a generalization of the hyperelastic membrane-type adhesion model to the hyperelastic beam case. In the modeling process, the variational method is used to derive the equilibrium equation and associated boundary conditions, including one that physically means the local peeling (fracture) criterion. A first integral is found for hyperelastic beams and it is used to derive an equivalent global peeling criterion. Moreover, an analytical formula for the peeling force during steady peeling is also obtained. Furthermore, numerical solution procedures and results are presented to discuss the effects of large strain and bending deformation on the peeling behavior of the hyperelastic beam. The developed model will contribute to the modeling and understanding of the adhesion and fracture behaviors of soft structures and biomimetic adhesives.

Tough, adhesive and conductive polysaccharide hydrogels mediated by ferric solution

In general, chitosan should be dissolved in strong acidic media (such as acetic acid) before it could be applied as hydrogels. However, it was found that chitosan could also be dissolved in the ferric solution to form ferric-chitosan complex via coordination interaction. Subsequently, the ferric-chitosan complex was successfully introduced into the hydrogel system to obtain tough, adhesive and conductive chitosan-polyacrylamide double network (CS-PAAm DN) hydrogels. Surprisingly, CS-PAAm DN hydrogel could repeatedly adhere to various solid materials and biological tissues through physical interactions. The maximum peeling force was 256 N/m on the aluminum surface. Moreover, the hydrogel exhibited adequate mechanical performance (135 kPa, 2332%). And the introduction of ferric chloride could also endow the hydrogel with conductive performance. As a result, the strategy based on tough, adhesive and conductive polysaccharide hydrogels mediated by ferric solution would broaden the path to fabricate a new generation of soft materials for wide applications.

Adhesion strength of plated Ni/Cu metallization in Si solar cells

Replacing silver paste contacts in silicon solar cells by electroplated nickel and copper (Ni/Cu) connections offer potential advantages of more exceptional grid lines, lower series resistance, and reduced costs in industrial silicon solar cell manufacturing. To achieve acceptance in the market for an electroplated Ni/Cu contacts sufficient contact adhesion has become the significant issue. In this work, a thin nickel layer was deposited on textured (001) silicon by an electroless plating method and form silicides by annealing treatment—this substrate designed as Ax–Si. Afterward, the Cu(15µ m)/Ni(240–1440 nm)/Ax–Si were prepared by electroplating techniques. The structures of Cu/Ni/Ax–Si characterized by scanning electron microscopy, transmission electron microscope and powder X-ray diffraction. Peel force tests were conducted using a universal testing machine. The peel force tests performed at an angle of 90° with a constant speed of 30 mm/min. Excellent adhesion force with 5.2 N/mm achieved.

Fatigue Damage Analysis of Composite Insulator Cor Rod/sheath Interface

A self-made fatigue testing machine was used to simulate the damage process of the insulator interface under working conditions and the damage degree is evaluated by the compressive shear test. The improved interface adhesion model reflects the interface debonding process under different fatigue loads by introducing the damage coefficient χ, migration coefficient α and the debonding coefficient μ. The relationship of fatigue loads and interface damage is established by the peeling force, the unit interface separation work and the peeling time. The test demonstrates that the interface damage near the bottom of the insulator is worse than that near the middle part. The result of this analysis will be beneficial in easily finding damaged places of the insulator, and so as to reduce the power breakdown.

Unsteady peeling accompanied by oscillations of adhesive tape from a soft adherend.

Peel angle dependence of the peel force was investigated using cross-linked polydimethylsiloxane (PDMS) covered with a pressure-sensitive adhesive tape. In our previous report, the peeling behavior at peel angles below 90° was discussed. The study revealed that an unsteady peeling occurs due to the extreme effects of the shear force on the adhered portion of the tape before the peeling starts. In this paper, we studied the peeling behavior and unsteady peeling accompanied by oscillations at peel angles higher than 90°, which is different from unsteady peeling at peel angles lower than 90°. The appearance of unsteady peeling accompanied by oscillations depended on the experimental conditions and material properties. Specifically, unsteady peeling was observed when the peel velocity, peel angle, and the thickness of PDMS were increased. Additionally, a decrease in the degree of cross-linking in PDMS also resulted in unsteady peeling. The periodic length of the oscillation was obtained from the peel force curves, which depended on the thickness and elasticity of the adherend. This unsteady peeling resulted from the large deformation of the adherend and the buckling of the tape due to the shear and compressive forces. In this paper, the mechanism of unsteady peeling was discussed on the basis of the classical models of mechanics.

Adhesive and Cohesive Peel Force Measurement of Human Airway Mucus.

In health, the high-speed airflow associated with cough represents a vital backup mechanism for clearing accumulated mucus from our airways. However, alterations in the mucus layer in cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) leads to the mucus layer adhered to the airway surfaces, representing the nidus of chronic lung infection. To understand what is different about diseased mucus and why cough clearance is defective, there is a need for techniques to quantify the strength of the interactions limiting the ability of airflow to strip mucus from the airway surface (i.e., adhesive strength) or tear mucus apart (i.e., cohesive strength). To overcome the issues with measuring these properties in a soft (i.e., low elastic modulus) mucus layer, we present here novel peel-testing technologies capable of quantifying the mucus adhesive strength on cultured airway cells and cohesive strength of excised mucus samples. While this protocol focuses on measurements of airway mucus, this approach can easily be adapted to measuring adhesive/cohesive properties of other soft biological materials.

Performance and testing of adhesive bandage tape

The adhesive plaster or bandage is used to cover non-serious wound or cut in the skin. It is formed by a basic layer of plain fabric coated with the adhesive material. There are several factors that affect the performance of the produced adhesive bandage. One of the frequent reported problems is the strong engagement with the skin that causes severe pain to the patient when it is removed from the skin. The peel test is used to determine the force required to remove the bandage from the skin, tissue or other adhesive tape. The aim of research is to study the factors that affect the performance of adhesive bandage—starting from the raw fabric used and some of the manufacturing machine settings (speed, slit knife height). An attachment was made to test the peeling force of adhesive tape on an ordinary tensile testing device. Results show that the storage of the adhesive bandage tape is the most significant factor that affects the mechanical properties of the adhesive tape.

Experimental Study on the Peeling Characteristics of Wax on the Surface of Flexible Composite Pipe and Plastic Alloy Tube

In this paper, the wax deposition stripping experiment on the surface of flexible composite tube and the surface of plastic alloy tube was carried out by using medical paraffin. Under different temperature and different thickness of wax, the peeling force of wax on the surface of flexible composite pipe and the surface of plastic alloy pipe lining was discussed. The experimental conclusions of this study are specific guidance for wax cleaning technology in nonmetallic pipes and device design.

Analysis of mortars used in the rehabilitation of wall coating

Two types of lime-based mortars were used in the rehabilitation of wall coverings, and the need to study their mechanical behavior and durability arose.About the mechanical behavior were analyzed flexural strength, compressive strength and the peeling stress at the "pull-off" test.As to durability, particularly in view of the rising damp and infiltration, this study was performed by capillary water absorption test and immersion due to water absorption at 48 (atmospheric pressure) for the determination of water content, focusing on its state of degradation, in order to mitigate the risks of choice.In this study, the results obtained in the tests of a traditional lime mortar with a 1: 3 volume trace with the samples of a prefabricated mortar of hydrated lime were compared, and in both mortars obtained values close to those recommended.However, the traditional hydraulic lime mortar has a peel force resistance well above the prefabricated mortar, and the recommended amount in domestic articles.

Spring Contact Model of Tape Peeling: A Combination of the Peel-Zone Approach and the Kendall Approach

Energy-based and force-based approaches are two basic ways to establish an adhesion model. For the adhesion of tape-like thin films, the Kendall equation considers the overall energy balance but inherently contains little information of the peel zone geometry and stress distribution. The peel zone model provides an empirical approximate of the peel front from the approach of a force description and coincides well with experimental results for a wide range of peel angles. However, the peel-zone model itself has not been unified with the Kendall equation yet. We propose a two-layer spring contact tape peeling model which considers the balance between the stretching force of the backing layer and the adhesive force transferred through the adhesive layer. The model provides an analytic shape description of the curved bifurcation region of the peel front. An approximate analytic solution of the peel force reduces to the Kendall equation by considering a Kendall-like energy conservation critical criterion, which further supports the proposed model. Further analysis of the relationship between the length of the peel zone and the adhesive force provides insight into the validity of the peel zone model. The proposed model provides a new insight in the tape peeling process and mathematically builds a potential bridge between the Kendall model and the peel-zone model.

Changes in Vitreoretinal Adhesion With Age and Region in Human and Sheep Eyes.

While several studies have qualitatively investigated age- and region-dependent adhesion between the vitreous and retina, no studies have directly measured the vitreoretinal strength of adhesion. In this study, we developed a rotational peel device and associated methodology to measure the maximum and steady-state peel forces between the vitreous and the retina. Vitreoretinal adhesion in the equator and posterior pole were measured in human eyes from donors ranging 30 to 79 years of age, and in sheep eyes from premature, neonatal, young lamb, and young adult sheep. In human eyes, maximum peel force in the equator (7.24 ± 4.13 mN) was greater than in the posterior pole (4.08 ± 2.03 mN). This trend was especially evident for younger eyes from donors 30 to 39 years of age. After 60 years of age, there was a significant decrease in the maximum equatorial (4.69 ± 2.52 mN, p = 0.016) and posterior pole adhesion (2.95 ± 1.25 mN, p = 0.037). In immature sheep eyes, maximum adhesion was 7.60 ± 3.06 mN, and did not significantly differ between the equator and posterior pole until young adulthood. At this age, the maximum adhesion in the equator nearly doubled (16.67 ± 7.45 mN) that of the posterior pole, similar to the young adult human eyes. Light microscopy images suggest more disruption of the inner limiting membrane (ILM) in immature sheep eyes compared to adult sheep eyes. Interestingly, in human eyes, ILM disruption was significantly greater in the posterior pole (p < 0.05) and in people over 60 years of age (p < 0.02). These findings supplement the current discussion surrounding age-related posterior vitreous detachment, and the risk factors and physiological progressions associated with this condition. In addition, these data further our understanding of the biomechanical mechanisms of vitreoretinal adhesion, and can be used to develop age- appropriate computational models simulating retinal detachment, hemorrhaging, or retinal trauma.