Rubber Alloy Research Articles

The Effect of Addition of Waste Materials on Nitrile Butadiene Rubber to the Mechanical Properties of Roller Rubber

This research aims to determine the effect of adding filler material in the form of waste material on Nitrile Butadiene Rubber (NBR) in making roller rubber to improve quality in terms of hardness and tensile strength. Each rubber roller compound is made from a mixture of NBR with rice husk, recycled rubber and wood charcoal. The process of making NBR and NBR with the addition of alloys is done with two roll open mixers at a certain temperature and time accompanied by the addition of certain additives. Furthermore, the compound is pressed using Hydrosan and then cut according to the standard test to be performed. The process ends by placing the material in an environment with a certain humidity level for 24 hours. Tests carried out include the test of hardness by using Shore A Durometer and Universal testing machines to test the strength of tensile strength. The test results show that the addition of recycled rubber can increase hardness by 30% when compared to NBR without the addition of filler. While the value of tensile strength for NBR and recycled rubber alloys is much higher.

Analysis on the lubrication characteristics of a few aqueous media that affect water lubricated rubber alloy bearing

The lubricating properties of water-lubricated rubber alloy bearings vary with different lubricating media. In this study, three types of media—pure water, saline, and sandy water—have been investigated using fluid-solid coupled numerical simulations and experimental methods. Lubricating properties, such as the water film pressure, rubber layer stress, and friction coefficient, are analyzed. The analysis shows that the water film pressure of the bearing generally increases and stabilizes with increasing rotational speed and eccentricity, but sandy water shows a greater increase compared with saline and pure water. The deformation and the stress of the carrying surface shows the same trend. In contrast, the friction coefficient decreases with increasing rotational speed and eccentricity in all of the different aqueous media, and it will gradually stabilize. Friction coefficient experiments and the analysis on wear status of the rubber were then carried out in the lubricating media mentioned. The analysis and tests show that sandy water has a great influence on the bearing lubrication properties. Therefore, it is an important factor for designing and using water-lubricated rubber alloy bearing.

Rheology of polypropylene/poly(ethylene-co-propylene) in-reactor alloy

The interfacial adhesion and molecular structure of an in-reactor polypropylene/ethylene propylene rubber alloy were studied with respect to the rheological behavior and final properties of the alloy. The polymer alloys have similar structural parameters but different impact properties. The samples were characterized by gel permeation chromatography, thermal analysis, rheological analysis and mechanical testing. Fractionation of samples showed that the quantities of components are the same. Gel permeation chromatography results showed that molecular weight distribution of all components were similar. Thermal analysis results showed that the crystal size of two samples was the same but the crystal contents were different. In studying the impact strength, it was revealed that a large difference exists between the two samples. The small amplitude oscillation rheometry indicates that the rheological parameters have a glaring difference in both samples that can be an evidence of interfacial adhesion in the in-reactor alloys having so many similar structural parameters.

Synthesis of spherical trans-1,4-polyisoprene/trans-1,4-poly(butadiene-co-isoprene) rubber alloys within reactor

Trans-polydiene rubber family as high-performance tire stock possessed excellent dynamic properties, including excellent anti fatigue, low rolling resistance, low heat buildup, good green strength, and low abrasion loss. Here, Reactor Granule Technology (RGT) was introduced into the field of synthetic rubber for the first time to produce trans-1.4-polyisoprene/trans-1,4-poly(butadiene-co-isoprene) rubber alloy, which showed significant improvement in rubber synthetic technologies and great development in abundance of trans-rubber family. A series of trans-polyisoprene alloys with excellent spherical morphology were successfully synthesized by using sequential multistage polymerization. The alloy was fractionated into four fractions by temperature-gradient fractionation, and the fractionation was analyzed by 1H NMR, 13C NMR, DSC and WAXD.

Numerical Analysis of Concave-Slab Type Water Lubricated Rubber Alloy Bearings’ Lubrication

By using ADINA’s fluid-structure interactions solver, 2-D numerical simulation for the lubrication performance of Concave-slab type water lubricated rubber alloy bearing was carried out under low rotating speed conditions. Then the pressure distribution, line load of the water lubricating film and the elastic deformation of slat-rubber lining were all obtained through the simulation.

Structural parameters in relation to the rheological behavior and properties of PP/EPR in‐reactor alloy synthesized by multi‐stage sequential polymerization

AbstractThe morphology and molecular structure of an in‐reactor polypropylene/ethylene propylene rubber alloy, synthesized by multi‐stage sequential polymerization, were studied with respect to the rheological behavior and final properties of the alloy. The polymer alloys, based on different structural morphologies, were characterized by SEM, GPC, 13C NMR, DSC, rheological analysis, and mechanical testing. The scanning electron microscopy of samples showed that the size of the dispersed phase particles is decreased as the switch frequency of copolymerization timing is increased. The GPC results showed that switch frequency slightly altered the molecular weight distribution of the copolymer although it had no effect on PP homopolymer. 13C NMR results were used for the evaluation of compatibility between the two phases with changes in switch frequency. DSC results showed that Tm and Tc were almost independent of switch frequency, even though the size of dispersed phase was decreased and the blend crystal content increased with ΔH of about 13%. The small amplitude oscillation rheometry showed that storage modulus and viscosity shifted to higher values when switch frequency increased. In studying the mechanical properties it was revealed that, especially the impact strength increased by about 62% when the size of the dispersed particles was decreased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Two-dimensional study of lubrication mechanism of water-lubricated rubber alloy bearing

Because of the high elasticity and low elastic modulus of rubber alloy, the accurate calculation of Elastohydrodynamic Lubrication (EHL) of water-lubricated rubber alloy bearing is complex. In this paper, the numerical analysis of lubrication mechanism of water-lubricated rubber alloy bearings is carried out by using multi-grid method. Curves of dimensionless film thickness and dimensionless pressure are drawn. The results indicate that on the dimensionless pressure curve second pressure peak does not exist and on the dimensionless film thickness curve the minimum film thickness appears on symmetrical axis without 'earlobe'. It is good for forming of EHL and friction-wear property is enhanced.

New generation of high-performance PVC alloys

Newly developed alloys of flexible poly(vinyl chloride) (PVC) and polyolefin elastomers have been shown to exhibit improved physical properties compared to those of conventional flexible PVC control compounds. In particular, the new alloys display enhanced electrical properties, better high temperature stability, greater low temperature flexibility, and superior gas barrier properties. In addition, this study demonstrated that PVC/polyolefin rubber alloys have potential utility in many applications where conventional flexible vinyl compounds do not meet certain end-use performance requirements.

Dynamic Vulcanization of Thermoplastic Copolyester Elastomer/Nitrile Rubber Alloys: II. Rheology, Morphology and Properties

The rheological, mechanical, morphological characteristics, and aging resistance in hot oil of thermoplastic elastomer based on multi-block thermoplastic copolyester elastomer (CPET)/nitrile rubber (NBR) have been in vestigated. The nitrile rubber is dynamically vulcanized during blending with thermoplastic copolyester elastomer. The etching technique was explored to conduct the SEM studies. The prepared thermoplastic elastomers possess ex cellent mechanical properties and good oil resistance.

Dynamic Vulcanization of Thermoplastic Copolyester Elastomer/Nitrile Rubber Alloys

New thermoplastic elastomers, copolyester (CPET)/nitrile rubber (NBR) alloys, were developed by using various dynamic vulcanization tech niques, such as internal mixing, open mill mixing, and twin screw extrusion, or their combinations. The effects of the various manufacturing techniques on rheological and mechanical properties were compared. The study showed that the dynamic vulcanization method by a twin screw extruder is most suitable for the manufacture of CPET/NBR elastomeric alloys.

Thermoplastic elastomers from NBR and polyvinyl chloride

AbstractThis paper will discuss recently developed technology that demonstrates the effectiveness of a thermoplastic polyvinyl chloride/nitrile rubber alloy versus commercially available thermoplastic elastomers and conventionally cured rubbers. Compounding variations, mixing and processing of thermoplastic elastomers such as low temperature properties, compression set, heat resistance, flex properties, and oil and fuel resistance will be examined. Compounding variations of the PVC/NBR allows will be explored to show how recipe changes can affect these important properties.