Adhesion Of Rubber Research Articles

THE EFFECT OF COPAL RESIN AND TURPENTINE OIL AS TACKIFIER ON THE ADHESIVES QUALITY BASED OF LIQUID RUBBER COMPOUND

This research aims to develop adhesives from liquid rubber compounds with a variety of tackifiers, a combination of copal resin, and turpentine oil. It also aims to characterize the adhesives to determine the quality of the adhesives produced. The research comprised several stages, including the preparation of rubber additive dispersions and solutions, formulation of liquid rubber compounds and adhesives, fabrication of test pieces, and subsequent characterization. The liquid rubber compound is made by mixing concentrated latex with rubber additives, which include KOH as a stabilizer, stearic acid and ZnO as an activator, BHT as an antioxidant, CaCO3 as a filler, MBTS and TMTD as an accelerator, and sulfur as a vulcanizer. The adhesives are made by mixing liquid rubber compound with tackifier material with various combinations of copal resin/turpentine oil, namely F1 (0 gram/4 gram); F2 (1 gram/3 grams); F3 (2 grams/2 grams), F4 (3 grams/1 gram), and F5 (4 grams/0 grams). Adhesives characterization was carried out by testing pH, viscosity, adhesives strength, FTIR, XRD, and thermal analysis. The research results showed that the best conditions were obtained on F4 adhesives with an adhesives strength value of 1.7452 N/mm, viscosity of 1100 cP, and pH 4.6. In this condition, the resulting adhesives meet the requirements for adhesives in accordance with SNI 06-6049-1999 and SNI 12-7195-2006.

Static and dynamic analysis of silicone/polyurethane embedded GFRP composite for magnetorheological elastomer

The current study focuses on the static and dynamic properties of GFRP composites embedded with a silicone(Si)/polyurethane(PU) blend used in automobile vibration dampening. Epoxy resin, glass fiber, and Si/PU blends of various compositions were used to create the hybrid composite specimens. For the present study, five different Si/PU blend compositions were considered to make five Si/PU embedded GFRP composite laminates were fabricated by hand layup method. The fabricated laminateswere cut to the standard sizes using water jet machining for mechanical and vibration testing. All tests were carried out in accordance with ASTM standards. Free Vibration test of five elastomeric composite specimens was carried out by impulse hammer method under fixed-free boundary condition. The current study found that the hybrid composite specimen with 0% Si and 100% PU elastomer has higher tensile strength, impact energy, and natural frequency than the other Si/PU blend elastomeric composite specimens.The better interfacial adhesion of PU rubber helps to transfer stress across interfaces more effectively and thereby enhancing the overall mechanical integrity of the composite laminate.

Solvent and low temperature resistant natural polyphenolic adhesives

The development of robust and bioinspired adhesives with excellent performances including fast gel time, low cost, good adhesion strength and stability, and excellent solvent and temperature resistance against harsh environment is urgent for practical applications. In this paper, kinds of natural polyphenolic adhesives have been successfully fabricated via the multiple polyphenol-diisocyanate cross-linking (PDC) reactions between natural polyphenols (extracts) and diisocyanate molecules. Under heating, as-prepared adhesives could effectively adhere onto a wide range of substrates (i.e. PTFE, PET, PMMA, Al, Cu, paper, glass, wood) through hierarchical interactions. Moreover, these adhesives exhibited great adhesion stability against complex solvents and low-temperature environments, whose adhesion strength could remain unchanged after soaking solvents after 30 days, which was conducive to their potential applications in industry and chemical fields, including petroleum, wood, metal, glass, plastics, and rubber adhesion. We believed that this work would provide new strategies towards the preparation of robust adhesives with excellent resistant against various solvents and low temperature for many fields by using naturally occurring building blocks.

A Study of the Friction Characteristics of Rubber Thermo-Mechanical Coupling.

The friction performance of tread rubber is related to the safety of the vehicle during driving, especially in terms of shifting speeds, cornering, and changing environmental factors. The experimental design used in this paper employed a self-developed automatic multi-working-condition friction tester to investigate the correlation between the friction coefficient of three tread formulations and various factors, including speed, pressure, temperature, side deflection angle, and lateral camber. This experimental study demonstrates that the coefficient of friction decreases with increasing load and increases with increasing sliding velocities due to changes in adhesion friction. Due to the increasing and decreasing changes in rubber adhesion and hysteresis friction caused by temperature, the coefficient of friction shows a tendency to increase and then decrease with the increase in temperature; thus, temperature has an important effect on the coefficient of friction. Based on the basic theory of friction and experimental research, the Dorsch friction model was modified in terms of temperature, and the analytical relationship between the rubber friction coefficient and the combined variables of contact pressure, slip velocity, and temperature was established, which is more in line with the actual situation of rubber friction. The model predictions were compared with the experimental results, and the error accuracy was controlled within 5%. This verifies the accuracy of the model and provides a theoretical basis for the study of rubber friction.

Evaluation of styrene butadiene rubber asphalt modification mechanism and adhesion effect based on molecular simulation

Recycled rubber materials represent an environmentally sustainable option as asphalt modifiers. This research delves into the modification effects of Styrene Butadiene Rubber (SBR) asphalt at varying SBR content levels, employing a blend of molecular simulation techniques and laboratory experimentation. A comprehensive molecular model of SBR-modified asphalt is established, and molecular dynamics simulations are executed to scrutinize the thermodynamic attributes, dipole moments, mechanical characteristics, and adhesion properties inherent to SBR asphalt. The outcomes of this inquiry reveal that SBR exhibits notable compatibility with a majority of asphalt molecules, as evidenced by their dipole moments. The introduction of SBR into the asphalt matrix results in the adsorption of a substantial quantity of lightweight components, fostering the formation of a cross-linked network that bolsters the asphalt's resilience against external deformation forces. Furthermore, in terms of adhesion work, asphalt demonstrates heightened affinity with alkaline aggregates, and SBR serves to augment van der Waals interactions at the asphalt-aggregate interface, thereby amplifying interfacial bonding strength. However, when the content of SBR reaches 30%, some SBR molecules will be aggregated in the asphalt, which will lead to phase separation and affect the stability of the colloid. Therefore, it is recommended that the content of SBR should be limited to about 20% in practical engineering applications. In this work, the modification mechanism of SBR was analyzed at the molecular scale and verified experimentally, and the results provide a theoretical basis for the rational use of recycled SBR powder in asphalt applications.

HET-CAM test in evaluation of irritating action of adhesives used in shoe making industry

The global tendency of the contemporary scientific studies is using alternative biologic models as substitutes of experimental animals. HET-CAM (The Hen's Egg Test on the Chorioallantoie Membrane Assay) is an alternative to in vivo tests involving experimental animals. This test is actively used in different biomedical studies. The aim of our work was to study the irritating potential of adhesives used in shoe making industry in experimental setting using the alternative HET-CAM method. Polyurethane, polychloroprene, rubber and styrene-butadiene adhesives that are widely used in shoe-making industry were studied . HET-CAM test was used for the evaluation of the irritating action of the aforementioned adhesives. All adhesives were applied directly onto the chorioallantoic membrane of chick embryos with reactions and changes (hemorrhages, vascular lysis and coagulation) observed and registered in 30, 120 and 300 seconds after the application of the adhesive. Irritating potential of the adhesives was evaluated according to a calculated irritating index. The most pronounced signs of irritating action were caused by polyurethane adhesives, namely hemorrhages and coagulation (30 sec) – two-component adhesive and hemor­rhages (30 sec) and coagulation (120-300 sec) – one-component adhesive. Vascular reactions from application of sty­rene-butadiene adhesives manifested predominantly with lysis and hemorrhages (30 sec), in some samples these reactions were observed at a later time-point (120-300 sec). Irritating action of rubber adhesives manifested mostly with hemor­rhages (30 sec), additionally one observation showed some lysis (120 sec). Polychloroprene adhesive caused hemorrhages (30-120 sec) and also lysis (30 sec) in one of the samples. According to the irritating index, polyurethane (one- and two-component) and styrene-butadiene adhesives were estimated to be strong irritants, while rubber and poly­chloroprene ones of moderate irritating action. НЕТ-САМ test can be used as a component in the evaluation of evidence of irritating action of shoe adhesives.

An eco‐friendly and high shear strength adhesive from catechol‐modified polyethyleneimine

AbstractConventional adhesives often emit volatile organic compounds (VOCs), which have a negative impact on human health. In this paper, an environmentally‐friendly supramolecular adhesive PD which has high adhesive and low VOCs emission is prepared by the reaction between polyethyleneimine (PEI) and 3,4‐dihydroxybenzaldehyde (DBA). PD containing abundant catechol groups exhibit excellent adhesion to wood substrates and is able to reach a maximum shear strength of 5.20 ± 0.39 MPa. One factor is attributed to multiple reactions between PEI, and DBA and oxidation of DBA. These reactions construct a complex three‐dimensional cross‐linked structure which is very helpful to improve the bonding performance of the adhesive. Another reason refers to the fact that a large number of catechol groups in PD can form a lot of hydrogen bonds with the amino group in PEI and the hydroxyl group in the wood substrate. These hydrogen bonds play an important role in enhancing shear strength. PD adhesives have a stronger bond strength than commercial chloroprene rubber (CR, Pattex‐PXL) and polyvinyl acetate adhesives (PVAc, JUJU‐8708) and have lower emissions of VOCs. As an environmentally‐friendly adhesive for wood‐based substrates, this adhesive may have potential applications in the wood processing industry.

Simulation of fluid driven crack propagation along metal/elastomer interface - Application to the numerical analysis of the rubber cord adhesion inflation test

The Rubber Cord Adhesion Inflation Test (RCAIT) has been proposed as an alternative technique to more standard pull out protocols such as H, T or pull out tests for characterizing the adhesion between cord/cable reinforcement and rubber. During this test, a fluid is injected in between a wire and a rubber cylindrical envelope to provoke the interface separation once a critical pressure is reached. A simple energy balance analysis is used to evaluate the critical strain energy release rate, GC, which drives the crack propagation from measurable quantities. However, some assumptions should be assessed to ensure reliable GC evaluation. Then, a predictive finite elements simulation of the RCAIT is proposed to simulate the fluid driven crack nucleation and propagation process along the rubber cord interface. These results are compared with the ones obtained from the RCAIT simplified analysis.

Silanization of functionalized PET fabric to improve PET-nitrile rubber (NBR) adhesion; effects of functionalization type and silane concentration

Surface modification could increase affinity of PET fibers to polymer matrix by changing the interfacial physical interactions to covalent bonds. In this research, surface modification of a superfine polyethylene terephthalate (PET) fabric was performed by bis(triethoxysilylpropyl)tetrasulfide (TESPT). The surface grafting was performed at different silane concentrations (i.e. 1, 5 and 10X). Before silanization, the fabrics were functionalized using photochemical method (i.e. irradiation of UV light in presence of glutaric acid peroxide (GAP)) and also hydrolysis by Sodium hydroxide (NaOH). Due to functionalization, carboxyl and hydroxyl groups were formed on the PET surface that made it ready to condense with hydrolyzed silane molecules. The fabrics were characterized using FTIR, TGA, FE-SEM, XPS analysis for evaluation of grafting performances. XPS analysis confirmed the presence of new peaks of Si and S after surface modification with TESPT. Comparing the results of TESPT-grafted functionalized PETs, it was found that the silane grafting content on PET surface is dependent not only to the silane concentration but also to the functionalization method. Finally, the influences of silane grafting on the functionalized PET fabrics to NBR adhesion were evaluated using H-pull and T-peel tests. The results showed that silane grafted-carboxylated PET fabric illustrated more adhesion to NBR than silane grafted-hydroxylated PET (i.e. 33 and 12% improvement in the pullout strength and T-peel adhesion, respectively).

Enhancing the interfacial adhesion of PET and silicone rubber by plasma-assisted coupling agent treatment

The poor interfacial adhesion between silicone rubber and polyethylene glycol terephthalate (PET) affects the safety and durability of fabric-rubber products in service. In this study, a low-cost and simple atmospheric plasma surface treatment device is used to treat the surface of polyester fabric continuously, followed by coating KH570 onto the fabric surface. The adhesion strength of fabric-rubber interface is successfully enhanced by this method. The peel strength of the specimens treated with this bonding process reaches 3.92 N/mm and 5.73 N/mm in the warp and weft directions, respectively, which are 5.16 and 7.44 times of untreated fabric samples, superior to commercially-available silicone rubber adhesive. In addition, the bonding mechanism of the interface is characterized by Fourier transform infrared spectra (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and water contact angle test. This study provides a practical and environmentally friendly method for fabricating fabric silicone rubber materials with high interfacial performances.

Synthesis of a siloxane oligomer containing methyl acryloxy group for promoting the adhesion of addition-type silicone rubber to copper plate

An adhesion promoter containing methyl acryloxy group was synthesized according to a non-hydrolysis sol-gel method with methyl phenyl silicone oil containing hydroxyl terminal group, methyl vinyl dimethoxy silane, and γ–methyl acryloxy propyl methyl dimethoxy silane (KH572) as raw materials and then applied in an addition-type silicone rubber. The structure of the product was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectrum (1H NMR). In addition, scanning electron microscope (SEM), mechanical testing machine and video-based optical contact angle measuring instrument were used to test its performance. We found that the adhesion promoter largely improved the bonding performance of the addition-type silicone rubber and showed the better compatibility with liquid silicone resins. When the amount of the adhesion promoter was 2.0 phr, the shear strength between silicone rubber and copper plate reached 1.33 MPa. The optical performance test results indicated that the light transmittance of silicone rubber was slightly changed when the addition amount of the adhesion promoter was no more than 2.0 phr, and this met the encapsulation requirements of electronic packaging adhesives. The contact angle test results indicated that the adhesion promoter reduced the static contact angle between the liquid silicone rubber and copper plate surface and improved the wettability. In addition, oxidation experiments, thermal resistance experiments, SEM tests and XPS surface analysis preliminarily proved that the adhesion promoter could significantly enhance the adhesion via chemical bonds formed with both the cured silicone rubber and the surface of copper plate substrate.

Characterisation and adhesion properties of UV-cured natural rubber-based adhesives

The adhesion properties of rubber adhesives based on SMR-L, ENR-25 and ENR-50 elastomers cured by ultraviolet (UV) light radiation were examined. Various parameters were studied, namely the effects of UV radiation dosages and coating thickness on adhesion properties such as tackiness, peel strength, and shear resistance. Prior to curing, the viscosity of uncured adhesives was analysed in order to understand the effect of adding benzoyl peroxide cross-linker. The reduction of double bonds due to UV-curing was confirmed by FTIR analysis. These adhesives were properly cured after 15 passes (repetitive irradiation on moving conveyor belt) inside UV-curing machine, as proven by both pendulum hardness and gel content tests. Results indicated that for all rubber-based adhesives, 120 μm coated samples showed higher peel strengths than their 60 μm counterparts. ENR-25 based adhesives showed better peel strength as compared to the others, while SMR-L based adhesives possessed higher tackiness and shear resistance than those of ENR-25 and ENR-50 based adhesives.

Tough tetrazine-functionalized styrene–butadiene rubber with self-adhesion through zinc–nitrogen coordination

This paper reports a feasible system for the direct adhesion of cross-linked rubbers, by incorporating tetrazine ligands into a styrene–butadiene rubber followed by the addition of zinc dimethacrylate with the aim of forming reversible cross-links.

ПРИМЕНЕНИЕ АГРЕГАТНЫХ ТЯГОВЫХ ПРИВОДОВ ДЛЯ ЛОКОМОТИВОВ С ПОВЫШЕННЫМИ ТЯГОВЫМИ СВОЙСТВАМИ

In order to implement the increased traction power of locomotives, rational solutions of traction drives with an aggregate layout are considered as a more technologically advanced alternative to integrated traction drives of foreign companies. As a result of the know-why analysis, the following was established: the use of an integrated circuit is induced by the objective of developing a drive for locomotives with different track gauge; the transition to an aggregate layout requires an increase in the axial dimension of a traction drive, the creation of an elastic-compensating coupling, operable at a rotational speed of up to 4000 min-1, and an increase in the number of bearings in the drive. It is grounded that it is possible to increase the dimensions of the locomotive’s 1520 mm gauge drive to equip it with a coupling joint of a maximum diameter of 570 mm and an axial dimension of 200 mm, as well as the technical possibility of creating a workable elastic-compensating coupling joint with rubber elastic elements in these dimensions according to the conditions of adhesion of rubber with metal. The structural layouts of an aggregate traction drive are proposed, allowing to reduce the number of bearings in it, as well as an aggregate traction drive with elastic support on the axle, which makes it possible to use such a drive for passenger locomotives with the wheels of 1220-1250 mm diameter.

Binary Promoter Improving the Moderate-Temperature Adhesion of Addition-Cured Liquid Silicone Rubber for Thermally Conductive Potting.

The strong adhesion of thermally conductive silicone encapsulants on highly integrated electronic devices can avoid external damages and lead to an improved long-term reliability, which is critical for their commercial application. However, due to their low surface energy and chemical reactivity, the self-adhesive ability of silicone encapsulants to substrates need to be explored further. Here, we developed epoxy and alkoxy groups-bifunctionalized tetramethylcyclotetrasiloxane (D4H-MSEP) and boron-modified polydimethylsiloxane (PDMS-B), which were synthesized and utilized as synergistic adhesion promoters to provide two-component addition-cured liquid silicone rubber (LSR) with a good self-adhesion ability for applications in electronic packaging at moderate temperatures. The chemical structures of D4H-MSEP and PDMS-B were characterized by Fourier transform infrared spectroscopy. The mass percentage of PDMS-B to D4H-MSEP, the adhesion promoters content and the curing temperature on the adhesion strength of LSR towards substrates were systematically investigated. In detail, the LSR with 2.0 wt% D4H-MSEP and 0.6 wt% PDMS-B exhibited a lap-shear strength of 1.12 MPa towards Al plates when curing at 80 °C, and the cohesive failure was also observed. The LSR presented a thermal conductivity of 1.59 W m−1 K−1 and good fluidity, which provided a sufficient heat dissipation ability and fluidity for potting applications with 85.7 wt% loading of spherical α-Al2O3. Importantly, 85 °C and 85% relative humidity durability testing demonstrated LSR with a good encapsulation capacity in long-term processes. This strategy endows LSR with a good self-adhesive ability at moderate temperatures, making it a promising material requiring long-term reliability in the encapsulation of temperature-sensitive electronic devices.

Adhesion of liquid silicone rubber (LSR) polypropylene (PP) composites after storage tests

The objective of this study is the production of liquid silicone rubber (LSR) polypropylene (PP) composites. To create adhesion between LSR and thermoplastics, self-adhesive LSR types are available on the market. However, these materials are not effective for commodity thermoplastics, such as PP and no adhesion can be achieved between these two components. Therefore, the PP surface was activated by means of silicatization (flame treatment). Subsequently, the LSR was applied on the activated PP by an overmolding injection molding process. After sample production a further focus was on post-treatment processes on the adhesive bond. Therefore, the entire composites were temperature stored. Peel tests according to the VDI guideline 2019 were carried out to examine the influence of the temperature storage on the peel resistance. Furthermore, the single components were examined separately by means of thermal, mechanical, and morphological tests to detect influences on the adhesion properties after storage.

Effect of Carbon Nanofibers on Physical, Adhesion and Rheological Properties of Liquid Epoxidized Natural Rubber Modified Asphalt

This study aimed to evaluate the effects of carbon nanofibers (CNFs) on the performance of liquid epoxidized natural rubber (LENR)-modified asphalt. The physical, adhesion and rheological properties were determined by several tests such as penetration, elastic recovery, ring and ball softening point, Brookfield rotational viscometer, AFM and dynamic shear rheometer. LENR was used at concentrations of 3, 6, and 9%, while CNFs were used at contents of 0.3, 0.4, and 0.5% by weight of asphalt. Conventional test results showed that the increases in LENR and LENR/CNFs composite contents in binder leads to an increase in the hardness and consistency and a reduction in the temperature susceptibility of base asphalt. Adhesion results revealed that the addition of CNFs significantly increases the adhesion and bonding properties of base and rubberized binders. Rheological properties analysis exhibited that LENR improved the viscoelastic properties and permanent deformation resistance of asphalt at different temperatures and frequencies. On the other hand, it was found that the addition of CNFs significantly improves the stiffness, elasticity, and hardness of LENR-modified binders. The 6% LENR and 0.4% CNFs were found to be the optimum to enhance the physical, adhesion, and rheological properties of asphalt in this study. Thus, it can be stated that the addition of CNFs is promising to improve the performance of rubberized binders for high temperature applications.

Influence of Modified Epoxy Dian Resin on Properties of Nitrile-Butadiene Rubber (NBR).

Due to the increasingly higher requirements for rubber vulcanizates, following the example of previous research on the effect of resin addition on mechanical properties and adhesion of rubbers, the following studies investigated the relationship between the addition of adipic acid-modified epoxy dian resin (ED-24 AK) to butadiene-acrylonitrile rubber (NBR). It can be seen that the addition of ED-24 AK, compared to the reference additive ED-20 (Epidian 5), additionally increase crosslinking density of the system, changes its mechanical and tribological properties, and exerts a positive effect on adhesion of the rubber vulcanizates to glass fiber. ED-20 and ED-24 AK resins do not enter the structure of the vulcanized rubber but act as the additives. ED-20 acts without changes in its structure, and ED-24 AK is a partially crosslinked additive. Modification, especially with ED-24 AK, makes mechanical strength of NBR increased even up to 240% in comparison to virgin rubber vulcanizate. This is responsible for lower friction of the vulcanizates. The decrease in the friction force of NBR due to the modified dian resin addition can reach up to 40%. Adhesion of the modified NBR to glass fibers increases due to its modification with the epoxy resins, however this time the ED-24 is more efficient than ED-24 AK reaching ca. 50% increase comparing to ca. 20% improvement, respectively. The best performance of the resins Generally, the best modification results were obtained when the addition of resins did not exceed 5 phr.

Effects of Curing Temperature and Adhesion Promoters on Adhesion of Addition-cure Liquid Silicone Rubber

Effects of Curing Temperature and Adhesion Promoters on Adhesion of Addition-cure Liquid Silicone Rubber

The effect of Magnesium resinate complex on the peel strength of polychloroprene-based rubber adhesive

ABSTRACT Magnesium resinate complex as one of the main components of the formulation of rubber adhesives based on polychloroprene, plays a major role in the adhesion strength of this type of adhesive. In the present research, first the optimum conditions for the formation of magnesium resinate complex was obtained by choosing different solvents and also different amounts of water as catalyst. To this aim, different samples of magnesium resinate complex were formed by the reaction between para-t-butyl phenol resin with magnesium oxide in the presence of water catalyst. Using DSC, FTIR and EDX it was found that toluene is better and more suitable solvent for the formation of magnesium resinate complex. Also, the optimum amount of water as catalyst for the formation of Magnesium resinate complex was determined about 0.66 wt% in solid content. The results of peel strength tests (180º peel) indicated that the adhesive that its Magnesium resinate was formed in toluene in the presence of 0.66 wt% of water as catalyst, had the highest strength. The peel strength of this formulation was determined about 8.57 N/mm and 9.62 N/mm after 4 days and 7 days storage at room conditions, respectively.