Hysteresis Loss Ratio Research Articles

Exploring experimental and finite element analysis to examine nano zinc oxide as a replacement for rubber‐grade zinc oxide in passenger car tire bead filler compounds

AbstractThe investigation demonstrates the potential of nano zinc oxide as a substitute for conventional rubber grade zinc oxide in the bead filler compound of passenger car tires, aimed at reducing heat generation while preserving mechanical and reinforcement properties. Experimentation showed that introducing nano zinc oxide increased compound viscosity, indicating enhanced filler networking. Cure rates accelerated due to the higher surface area of nano zinc oxides, while the Payne effect indicated improved dispersion levels in experimental compounds. Notably, the variant with four parts per hundred rubber of nano zinc oxide exhibited mechanical properties akin to the control, alongside a 28% reduction in tan δ and improvements in hysteresis loss ratio and specific heat values. Morphological analysis confirmed superior dispersion in experimental compounds. Finite element analysis demonstrated decreased temperature generation and a reduced percentage contribution of the bead filler to overall heat energy in tires, leading to a 3% drop in rolling resistance. These findings suggest that nano zinc oxide can effectively replace conventional zinc oxide, enhancing fuel economy in tires, thereby offering a green initiative to reduce fuel consumption in passenger car radial tires through improved hysteresis at the bead area via bead filler compound modification.Highlights Nano zinc oxide replaces rubber grade zinc oxide reducing heat generation. Nano zinc oxide improves compound viscosity, enhancing filler networking. Variant with four parts per hundred rubber of nano zinc oxide matches control's mechanics, with 28% lower tan δ. Morphological analysis confirms dispersion, coupled with aggregation. Simulation shows lower temperature generation and 3% less rolling resistance.

Compressive Stress-Strain and Rebound Resilience Properties of Deproteinized Natural Rubber Latex Foam

Deproteinized natural rubber (DPNR) latex is a modified version of natural rubber (NR) latex that is hypoallergenic and odorless when used in products. However, due to the lack of studies in this field, there are relatively few DPNR latex foam products to date. Our laboratory has developed a novel manufacturing technique that involves a heat-enzymatic reaction followed by a concentration procedure to generate DPNR latex directly from freshly tapped latex and to manufacture a novel DPNR latex foam using the Dunlop batch foaming procedure. To investigate the mechanical properties of the foam, ball-rebound resilience studies and compression tests were conducted on DPNR latex, commercial grade polyurethane (PU) and polyurethane memory (PM) foams as a comparison. Compressive stress-strain study revealed that the hysteresis loss ratio of DPNR latex foam, PU foam, and PM foam is 0.19, 0.66, and 0.86, respectively. DPNR latex foam exhibits the lowest hysteresis loss ratio due to its elastic behavior thus able to store a high amount of energy when under compressed. On the other hand, the rebound resilience of DPNR latex foam, PU foam, and PM foam is 74%, 29%, and 9%, respectively, indicating that DPNR latex foam has the highest rebound resilience. The resilience property is correlated with the elasticity, dimensional stability and durability of foam materials. Thus, DPNR latex foam is suitable for heavy-duty cushion applications including seats for transportation industry.

Supercritical CO2Foaming of Lightweight Polyolefin Elastomer/trans-Polyoctylene Rubber Composite Foams with Extra-Soft and Anti-Shrinkage Performance

Lightweight polyolefin elastomer (POE) foams are of great interest in numerous fields. However, POE is difficult to foaming and obtaining the ideal cellular structures before cross-linking. Herein, low-molecular-weight trans-polyoctylene rubber (TOR) with lots of double bonds and low molecular weight was introduced into the POE matrix to improve their vulcanizing and foaming process. Then, a series of lightweight POE/TOR composite foams with adjustable cellular structures and outstanding performance were prepared by supercritical CO2 foaming. It was worth noting that the gel content and foaming temperature windows were greatly improved under the action of TOR, and a record-breaking density as low as 0.036 g/cm3 for POE-based composite foams was harvested. In addition, the as-prepared elastomer foams exhibited rapid shrinkage but slow recovery feature due to the diffusivity difference of gas and cross-linking nature of materials, and its recovery ratio could reach 91.3%. More interestingly, the conversion law of the corresponding density change between hard and soft materials was discovered, and extra-soft POE-based composite foams (like Shore C below 10) were obtained, which could be twisted, folded, compressed, stretched, bent, and rolled with ease. Furthermore, the residual strain and hysteresis loss ratio of as-prepared elastomer foams were as low as 1.56 and 12.95%, respectively. These distinct advantages together with the green foaming process make the composite elastomer foams very promising toward high-performance flexible cellular polymeric materials.

SPECIALTY NATURAL RUBBER LATEX FOAM: FOAMABILITY STUDY AND FABRICATION PROCESS

ABSTRACT Specialty natural rubber (SpNR) latex, namely, deproteinized natural rubber (DPNR) latex and epoxidized natural rubber (ENR) latex, has been produced to meet specific product's requirements. However, SpNR is normally used in the form of block rubber to manufacture dry rubber products such as tires and automotive parts. The applications of SpNR latex into latex foam products will be diversified. Findings indicate that foamability of SpNR latex is lower compared to normal latex (LATZ) but shows longer stability time after foamed. Findings also indicate that foam collapse and foam coagulate are two main challenges in the fabrication process of SpNR latex foam. Despite these challenges, SpNR latex foam can be fabricated at different density levels. During the foaming process, additional foaming agent is required to fabricate a SpNR latex foam, which is different from fabricating a normal NR latex foam, especially at low latex foam density. Consequently, a higher level of sodium silicofluoride, used as the gelling agent, is required to set the cell structure of the foam. Findings also indicate that foam density influenced the gelling time and volume shrinkage of the SpNR latex foam. An ideal compounding, foaming, and gelling formulation to fabricate SpNR latex foam via Dunlop batch foaming process has been developed. Morphological study showed that all latex foams are open-cell structure, with lower density foam exhibiting higher porosity and mean pore size. Comparison on hysteresis behavior between DPNR and ENR latex foam indicated that ENR latex foam exhibits higher hysteresis loss ratio compared to DPNR latex foam.

Effect of ball scribing on power loss separation of Fe-3%Si grain-oriented silicon steel

Power loss of Fe-3%Si grain-oriented silicon steel was measured after ball scribing with different spacing using a self-designed tool. Three different sections of power loss, including hysteresis loss, abnormal loss, and eddy current loss, were measured and calculated, respectively. The loss variation and ratio were analyzed based on the experimental data. At 1.0 T, hysteresis loss of tested steel with scribing spacing of 8 mm descends by 8.2% compared to samples without scribing, which is similar to the total loss variation, and abnormal loss descends by 16.8%. At 1.0 T, hysteresis loss ratio of the steel with scribing spacing of 16 mm ascends from 55.7% to 57.9%, and eddy current loss increases from 17.4% to 24.1%, while abnormal loss descends from 26.9% to 23.7%. The experimental results show that the reduction of power loss after scribing is mainly due to decreasing of hysteresis loss and abnormal loss.

Effects of silane coupling agents on tribological properties of bentonite/nitrile butadiene rubber composites

In this work, effects of silane coupling agents on the tribological properties of bentonite/nitrile butadiene rubber (NBR) composites were investigated. The composites were fabricated with a facile method. Three silane coupling agents, (3‐mercaptopropyl)trimethoxysilane (MPTMS), bis[3‐(triethoxysilyl)propyl]tetrasulfide (TESPT) and [3‐(2‐aminoethylamino)propyl]triethoxysilane (AEAPTMS) were employed in our research. The short sulfur bonds formed between MPTMS and macromolecules in the matrices limited the extension of the contact interface between rubber matrices and glass plate, which contributed to the reduction in friction coefficient. With TESPT and AEAPTMS, the adhesion force of the composites was remarkably reinforced, further leading to the increase in friction coefficient. In the wear test, bentonite/silane/NBR composites showed better wear resistance compared to the specimens fabricated without silanes. By investigation on the morphological features of the worn surfaces, different wear mechanisms for composites with/without silane coupling agents were illustrated in detail. Generally, the effects of silanes to adhesion force, hysteresis loss ratio, and hardness all contributed to the friction coefficients of the composites. In wear test, the effects of the silanes on hysteresis force were prominent. Incorporated with MPTMS, the composite showed poor wear resistance due to its high hysteresis loss ratio. POLYM. COMPOS., 38:2347–2357, 2017. © 2015 Society of Plastics Engineers

High Strain-Rate Compressive Behavior of Bulk Structural Adhesives: Epoxy and Methacrylate Adhesives

The present paper describes the determination of high strain-rate compressive stress-strain loops for bulk specimens of two different epoxy and methacrylate structural adhesives on the standard split Hopkinson pressure bar with a tapered striker bar. The full compressive stress-strain data including unloading process are obtained over a wide range of strain rates from 10-3 to 103/s at room temperature. The effects of strain rate on the initial (secant) modulus, flow stress, dissipation energy and hysteresis loss ratio are studied. The experimental results show that both bulk structural adhesives exhibit highly strain-rate dependent viscoelastic behavior like polymeric materials.

High Strain-Rate Compressive Stress-Strain Loops for Structural Adhesive

The high strain-rate compressive stress-strain loops for bulk specimens of an epoxy structural adhesive are determined on the standard split Hopkinson pressure bar. The compressive stress-strain data including unloading curves are obtained over a wide range of strain rates from 10-3to 103/s. The effects of strain rate on the initial (secant) modulus, flow stress, dissipation energy and hysteresis loss ratio are discussed. The experimental results show that the bulk structural adhesive exhibits dynamic viscoelastic behavior like polymers.

Damping Properties of Eucommia ulmoides Gum and its Blends

The damping properties of Eucommia ulmoides gum (EU gum) and its rubber blends were systematically studied using hysteresis loss ratio and dynamic mechanical tests. The former method indicates that the hysteresis loss ratio of EU gum is much higher than that of other rubbers. Because the residual deformation of EU gum is very large, it cannot be directly used as an elastic damping material; it can only be used as a modifier of other rubbers to obtain elastic damping materials. The results show that EU gum can increase the hysteresis loss ratio of a number of rubbers. The latter method shows that EU gum can also increase E'' (loss modulus) of blended rubber; this is consistent with the results of the former method. A blend of EU gum/Nitrile -Butadiene rubber (NBR) is the best elastic damping material with the largest hysteresis loss ratio, E'', and low residual deformation (less than 20%). The contribution of EU gum to the damping property of blended rubber might be associated with the influence of the crystallinity of EU gum.

Relationship between mechanical properties and exfoliation degree of clay in polyurethane nanocomposites

AbstractExfoliated and intercalated polyurethane (PU) nanocomposites were prepared by in situ polymerization of polyol/organoclay mixture, chain extender and diisocyanate. Wide‐angle X‐ray diffraction and transmission electron microscopy confirmed an exfoliated structure for clay C30B and an intercalated structure for C20A in polyol and PU. The realization of exfoliated state for clay C30B in polyol during the mixing stage can provide an effective approach for controlling the exfoliation degrees by adjusting the content of intercalated and exfoliated organoclay C20A and C30B before polymerization. The effect of exfoliation degree on the mechanical and viscoelastic properties of PU was investigated. The addition of organoclay improved the tensile strength, modulus and elongation, but the hysteresis loss ratio and relaxation rate increased, and the relaxation time distribution became broad. The effect of organoclay on PU properties varied with the hard segment content. By increasing the exfoliation degree, the tensile strength and modulus increased, whereas the elongation decreased. The exfoliated PU nanocomposite had a lower relaxation rate and hysteresis loss ratio than the intercalated PU. Copyright © 2005 Society of Chemical Industry

Influence of Novel Electron Beam Modified Surface Treated Dual Phase Filler on Rheometric and Mechanical Properties of Styrene Butadiene Rubber Vulcanizates

Abstract Rheometric and mechanical properties, hysteresis and swelling behavior of the Styrene-Butadiene Rubber vulcanizates (SBR) filled with unmodified and novel electron beam modified surface treated dual phase fillers were investigated. Scorch time increases for these modified filler loaded vulcanizates due to introduction of quinone type oxygen on the surface. Electron beam modification of dual phase filler in the absence of trimethylol propanetriacrylate (TMPTA) or triethoxysilylpropyltetrasulphide (Si-69) significantly improves the modulus of the SBR vulcanizates, whereas the values of tensile strength and elongation at break drop. However, presence of TMPTA or silane slightly increases the modulus with significant improvement in tensile strength. This effect is more pronounced at higher loading of these modified fillers in SBR vulcanizates. These variations in modulus and tensile strength are explained by the equilibrium swelling data, Kraus plot and a new mathematical model interpreting the polymer-filler interaction. Hysteresis loss ratio of SBR vulcanizates loaded with irradiated fillers in absence and presence of TMPTA or silane increases due to highly aggregated structure of the filler.

High Strain Hysteresis Loss of Rubber Vulcanizates under Pure Shear and Constrained Extension and Influence of Filler

Abstract An experimental analysis of hysteresis loss, hysteresis loss ratio and input energy of natural rubber (NR) and styrene-butadiene rubber (SBR) vulcanizates having variations of loading of carbon black, precipitated silica and clay has been carried out under uniaxial, pure shear and constrained extension modes over a range of extension ratios (1.0 to 2.2 and 1.2 to 4.0 in X and Y directions, respectively), number of cycles (1 to 8) and temperatures (25 to 125 °C). Hysteresis loss, hysteresis loss ratio and input energy increase with an increase in filler loading, extension ratio (in both directions) and reinforcement. These parameters decrease with an increase of temperature and number of stretch cycle. Hysteresis loss, loss ratio and input energy under constrained extension are higher than those under pure shear and uniaxial modes. NR and SBR vulcanizates show similar behavior. Universal expressions relating energy input at any extension ratio, W1, to the hysteresis loss (Hy) as well as hysteresis loss ratio (Hy)r under uniaxial, pure shear and constrained extensions have been developed.

Effect of holding time on high strain hysteresis loss of carbon black filled rubber vulcanizates

AbstractHysteresis loss has been measured at constant stress and constant strain, at various holding times under tensile deformation of natural rubber (NR) and styrene‐butadiene rubber (SBR) vulcanizates filled with various loadings of carbon black filler. The effects of temperatures (25°C to 150°C), strain rates (3.78 × 10−5 sec−1 to 210 × 10−3 sec−1) and strain levels (20% to 300%) have been studied. Hysteresis loss and hysteresis loss ratio increase with an increase in strain rate, filler loading, strain level and holding time. It decreases with an increase of temperature. However, higher hysteresis loss and hysteresis loss ratio are observed at constant stress than at constant strain. NR and SBR vulcanizates show similar behavior. Evidence has been produced for the existence of a distinct relaxation process that occurs within first 120 second of holding time at room temperature. This process becomes less important as the strain or the temperature is increased. However, at high temperature another distinct relaxation process has been observed. The activation energy has been found to be 66.3 kJ/mole for the rates at the higher holding time, while it has been found to be 17.3 kJ/mole for the rates at the lower holding time using the data of hysteresis loss at first cycle of 40 phr black filled NR vulcanizates.

High‐strain hysteresis of rubber vulcanizates over a range of compositions, rates, and temperatures

Hysteresis loss of natural rubber (NR) and styrene–butadiene rubber (SBR) vulcanizates having variations of loading of carbon black, silica, clay, resin, and curatives has been measured over a wide range of strain rates and temperatures as well as under swollen conditions. Hysteresis loss increases with an increase in strain rate, filler loading, resin loading (at high rates), crosslink density, and strain level. Hysteresis decreases with an increase in temperature, particle diameter of filler, and resin loading at high testing temperature. All the data of hysteresis loss of filled NR and SBR compounds have been found to be superimposable on single master curves with the help of the WLF shift factor. The master curves can be divided into three regions. The slope of the intermediate region, Δlog(hysteresis)/Δlog(RaT) has been found to be 0.1 for almost all the vulcanizates. Similar master plots have been obtained when the hysteresis loss has been measured at higher cycles and higher extensions and also by using the data of the hysteresis loss ratio. The hysteresis loss ratio of all the vulcanizates follows a similar trend, except for the highly crosslinked system, which shows a lower value. Carbon black contributes significantly to the hysteresis loss even when the energy dissipation is minimized by swelling. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1429–1439, 1997

High-strain hysteresis of rubber vulcanizates over a range of compositions, rates, and temperatures

Hysteresis loss of natural rubber (NR) and styrene–butadiene rubber (SBR) vulcanizates having variations of loading of carbon black, silica, clay, resin, and curatives has been measured over a wide range of strain rates and temperatures as well as under swollen conditions. Hysteresis loss increases with an increase in strain rate, filler loading, resin loading (at high rates), crosslink density, and strain level. Hysteresis decreases with an increase in temperature, particle diameter of filler, and resin loading at high testing temperature. All the data of hysteresis loss of filled NR and SBR compounds have been found to be superimposable on single master curves with the help of the WLF shift factor. The master curves can be divided into three regions. The slope of the intermediate region, Δlog(hysteresis)/Δlog(RaT) has been found to be 0.1 for almost all the vulcanizates. Similar master plots have been obtained when the hysteresis loss has been measured at higher cycles and higher extensions and also by using the data of the hysteresis loss ratio. The hysteresis loss ratio of all the vulcanizates follows a similar trend, except for the highly crosslinked system, which shows a lower value. Carbon black contributes significantly to the hysteresis loss even when the energy dissipation is minimized by swelling. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1429–1439, 1997

Magnetization reversal mechanism in CoCr media for perpendicular recording

It has recently been shown [1] that hysteresis loss as a ftulction of the direction of the applied field can be used as a criteria to determine the reversal mechanism in CoCr films. In this paper we present hysteresis loss ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Wh/Wh\perp</tex> ) and orientation ratio (OR) as function of the amplitude and direction of the applied field for low and high <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Hc\perp/Hk</tex> sputtered CoCr films. The reversal behaviour depends strongly on the amplitude and direction of the field. The presence of all initial layer has an important influence on the type of reversal. The rotational mechanism governs the switching in high <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Hc\perp/Hk</tex> films while the domain-wall reversal acts in the low coercivity film.

TEXTURE PROFILE PARAMETERS OF COOKED FRANKFURTER EMULSIONS AS INFLUENCED BY COOKING TREATMENT2

Texture profile parameters of frankfurters were found to be generally related to cooking temperatures, except for degree of elasticity, hysteresis loss, and work ratio. Cohesiveness, elasticity, gumminess, and chewiness all were polynomial functions of cooking temperature and were smallest at 70‐75° C where physico‐chemical changes in proteins important to texture development appeared to be occurring. Hardness, compression energy of first bite, brittleness, apparent moduli of elasticity, stress at 20% compression and strain energy of compression per unit volume were all linearly related to the cooking temperature. Texture profile parameters were higher for samples with higher protein and lower moisture contents at all cooking temperatures.