Solid Rubber Research Articles

Sound insulation properties of two-layer baffles used in vibroacoustic protection

The subject of the research presented in the article was the modelling of acoustic properties of two-layer baffles, used in vibroacoustic protection. Baffles of this type are used, among others, in the construction of walls of the sound insulating enclosures of machines and devices. The heterogeneous single baffles that were analysed were panels made of two sound insulation layers, solid rubber and a steel plate. A sound insulation calculation model for heterogeneous single two-layer baffles used in vibroacoustic protection has been proposed. The model has been verified in relation to the laboratory tests of rubber-steel baffles of various thickness. The results of calculations were also compared with the spectral characteristics of sound insulation obtained with the use of the mass law and commercial software. Using the proposed calculation model, simulation tests of the sound insulation effectiveness of rubber-steel and rubber-aluminium baffles were performed.

Correction to: Influences of dielectric and conductive fillers on dielectric and mechanical properties of solid silicone rubber composites

The article listed above was initially published with incorrect Table 1 and Table 2 values.

Influences of dielectric and conductive fillers on dielectric and mechanical properties of solid silicone rubber composites

Dielectric elastomers are materials being used for electromechanical transduction applications. Their electromechanical response depends on permittivity, Young’s modulus and electric breakdown strength. A factor that limits its application is high operating voltages that can be reduced through improvement in permittivity. One of the methods is by incorporating high permittivity fillers into polymer matrix to obtain dielectric–dielectric composites (DDC).These composites show high permittivity at the cost of reduced flexibility. An alternative solution is development of composites by incorporating organic or inorganic conductive fillers into polymer matrix. These composites show high permittivity with high dielectric loss and low breakdown strength. To overcome both the above limitations both dielectric and conductive fillers are incorporated into dielectric polymer matrix to obtain conductor–dielectric composites (CDC). In this study, high temperature vulcanized solid silicone rubber as matrix has been used to prepare DDC composites with barium titanate (BT) filler and CDC composites with both BT as dielectric and ketjenblack as conductive fillers, using Taguchi design of experiments. The effect of factors such as amount of fillers and curing agent, mixing time in roll mill and curing temperature on the dielectric and mechanical properties are reported. Lichtenecker model predicts the permittivity of the DDC composite more accurately. For the CDC composites permittivity increased by 390%, effective resistivity decreased by 80%, Young’s modulus increased by 368% and Shore A hardness increased by 90% as compared to those of reference matrix. Important interaction effects are observed among both the fillers that are uniformly dispersed without any aggregation.

Numerical prediction and experiment of impact on rubber hydro unit with multi-chambers using an effective dynamic co-simulation approach

ABSTRACTAn accurate evaluation on dynamic impact response for rubber–metal components with fluid has been very challenging over many years, especially using three-dimensional dynamic co-simulation via fluid-structural-interaction (FSI) in time domain. There are also very limited successful cases reported on dynamic impact evaluation in vehicle applications. Natural frequency region (NFR) approach, based on computational solid dynamics, recently proposed by the author, has successfully evaluated dynamic response of rubber anti-vibration components without fluid. This method is extended to fluid using co-simulation with computational fluid dynamics (CFD). This combined approach, i.e. NFR–FSI–CFD approach, is applied to an impact simulation on a joint unit including two solid rubber springs and one shock mount with two pistons embedded in internal fluid chambers. The result of the simulation is validated with the experimental data. Eight key aspects are identified and main steps to effectively perform dynamic co-simulation are suggested. This proposed approach is designed for industrial practice to simulate rubber hydro anti-vibration systems as the detailed deformation and strain/stress profiles of the components can be obtained. The real stiffness of the anti-vibration system can be calculated from the load-deflection curve generated and employed for vehicle system dynamics.

Study of physical characteristic of rubberized hot mix asphalt based on various dosage of natural rubber latex and solid rubber

Currently, the implementation of rubberized asphalt technology become the main concern of Government in natural rubber producing countries, especially Thailand, Indonesia, and Malaysia. The policy is intended to increase natural rubber domestic consumption and support national infrastructure project. Rubberized asphalt is made from the mixture of hot asphalt with polymer such as natural rubber either in the form of latex or compound. For field implementation, rubberized asphalt should be mixed with aggregate to form rubberized hot mix asphalt. The research was conducted to study the rubberized hot mix asphalt characteristic at laboratory scale. Types of natural rubber were used consist of cationic natural rubber latex (L2), 4 hours prevulcanized natural rubber latex (L3), and semi-efficient solid natural rubber compound (KP2). The base asphalt used asphalt penetration 60/70, while the aggregate was obtained from Subang District, West Java, Indonesia. The trials were run at three stages i.e. analysis of pure asphalt and aggregate properties, determination of mixing and compaction temperature, followed with characterization of rubberized hot mix asphalt physical properties by using Marshall and Wheel Tracking Machine. The dosage of natural rubber addition was varied at 3,5,7 and 9%. Hot mix asphalt without rubber addition was used as control. The result showed that the addition of natural rubber into the asphalt penetration 60/70 raised the Marshall stability of rubberized hot mix asphalt. The initial Marshall stability value was 986 kg for pure hot mix asphalt became 1097 kg for 7% of cationic natural rubber latex, 1103 kg for 5% of 4 hours prevulcanized natural latex, and 1110 kg for 7% of semi-efficient solid natural rubber compound. Thus, it could be concluded that the addition of 5-7% natural rubber improved the physical characteristic of rubberized hot mix asphalt as indicated by the increasing of Marshall stability value.

A novel method to prepare acrylonitrile-butadiene rubber/clay nanocomposites by compounding with clay gel

Despite that there have been many reports on the achievement of high-performance rubber/clay nanocomposites, the preparation strategies of these nanocomposites are still quite limited. In this study, a novel method named gel compounding method was utilized to prepare acrylonitrile-butadiene rubber (NBR)/clay nanocomposites via compounding solid rubber with clay gels. As illustrated by TEM and XRD, clay was uniformly dispersed in the NBR matrix as either exfoliated platelets or very thin layered silicate stacks, indicating the separated structure was formed in the NBR/clay nanocomposite prepared by this gel compounding method. Mechanical properties were significantly improved for the NBR/clay nanocomposites, which reached the tensile strength of 12.1 MPa with 10 phr clay, more than 250% higher than that of pure NBR.

Mechanical and durability performance evaluation of crumb rubber-modified epoxy polymer concrete overlays

The epoxy-based polymer concrete has been widely used for concrete repairing and overlays due to good mechanical properties and durability. To reduce environmental landfill problems with the accumulation of tire rubbers, scrap tire rubbers were added to epoxy polymer concrete in this investigation. The crumb rubber (with mesh size #50, 0.279 mm) were introduced into epoxy concrete with two different contents of 5% and 10% based on the epoxy monomer weight. The mechanical properties including direct tensile strength, compressive strength, splitting tensile strength and interface bond strength. Thermal- and moisture-related durability performance of rubberized epoxy concrete were measured and compared with the control samples. The compressive strength and splitting tensile strength were improved with the added 5% solid rubbers, and slightly reduced with 10% content. With a specially-designed testing method, the interface tensile bonding strength between the epoxy concrete overlay and concrete slab were measured as higher than 250 psi for both control and rubberized samples. The thermal conductivity of polymer concrete was reduced with the increase of rubber contents. In addition, very low water absorption rates (<0.5%) were measured with all types of epoxy concrete samples. The interface microstructure with SEM also indicated the good bonds between rubber particles and epoxy resins. The overall test results showed the enhanced performance of rubber-modified epoxy concrete which can facilitate the tire rubber recycling into epoxy polymer concrete for protecting the exist concrete pavement structures.

High-Performance PZT-Based Stretchable Piezoelectric Nanogenerator

Stretchable piezoelectric nanogenerators are highly desirable for power supply of flexible electronics. Piezoelectric composite material is the most effective strategy to render piezoelectric nanogenerators stretchable. However, the generated output performance is unsatisfactory due to the low piezoelectric phase proportion. Here we demonstrate a high-performance Pb(Zr0.52Ti0.48)O3 (PZT)-based stretchable piezoelectric nanogenerator (HSPG). The proposed HSPG exhibits excellent output performance with a power density of ∼81.25 μW/cm3, dozens of times higher than previously reported results. Mixing technique, instead of conventional stirring technology, is used to incorporate PZT particles into solid silicone rubber. The filler distribution homogeneity in matrix is thus remarkably improved, allowing higher filler composition. The PZT proportion in composite can be increased to 92 wt % with satisfactory stretchability of 30%. On the basis of the excellent electrical and mechanical properties, the proposed HS...

Pengaturan Dosis Asap Cair Berbahan Baku Tempurung Kelapa Sebagai Bahan Penggumpal Lateks

In the processing of solid rubber, such as the manufacture of crumb rubber and rubber smoke sheet , o ne of the most important stages is the coagulation process using coagulant. The coagulation process is instrumental in determining for quality the rubber produced. Low quality of bokar is caused by farmers using coagulant which are not recommended. Because of that, it’s necessary to found the alternative coagulant that does not damage the quality and the price is relatively cheap. The purpose of this research is gets the best dosage of coconut shell liquid smoke for latex coagulation and to evaluate quality crepe rubber coagul um using coconut shell liquid smoke. The quality observed is dirt content, ash content, volatile matter, PRI, Mooney viscosity, and color index was implemented at PTPN VII , Way Berulu , Pesawaran District . The doses used were 0 , 1%, 1 , 5%, 2%, 2 , 5%, and 3%. The result showed that the most effective dose used in this research was 1% with quality approaching formic acid treatment. Keywords: coconut shell, formic acid, latex coagulant, liquid smoke

Factors influencing green strength of commercial natural rubber

Abstract The factors influencing the green strength of commercial solid rubbers were investigated in the present study through characterization of commercial natural rubber (NR). Various solid commercial rubbers such as standard Vietnam rubber (SVR10), standard Indonesia rubber (SIR10), India standard natural rubber (ISNR10), ribbed smoked sheets (RSS3), and FNR (commercial Sumitomo Rubber) were used as a source. Purification of the samples was carried out through acetone extraction and purified samples were characterized by nuclear magnetic resonance (NMR) and Fourier-Transform infrared spectroscopy. Degradation was found for SVR10, ISNR10, and SIR10 but not for RSS3 and FNR through the assignment of 13C-NMR signals. Acetone extraction was found to improve the green strength of commercial NR due to the removal of impurities. Linked fatty acids and proteins contributed to the upturn of stress at small strain. However, the network structure of degraded rubbers had an insignificant role in enhancing the green strength of commercial NR.

Measuring rubber friction using a Laboratory Abrasion Tester (LAT100) to predict car tire dry ABS braking

Abstract Evaluating tire grip on the road, an extremely complicated tribological system, is enormously energy and time consuming but essential for safety. To predict grip on the road, tires with four different tread compounds were tested on ABS braking distance on a dry test track. Corresponding solid rubber wheels were characterized on the Laboratory Abrasion Tester (LAT100) on four different electro-corundum discs of various grain sizes. With increasing speed the side force coefficient (SFC) decreases. A lower disc grain size induces a higher SFC. A correlation coefficient of 0.93 between the LAT100 data and road results for the four tread compounds has a high potential for predicting the car tire ABS braking distance.

PENGUJIAN PERKERASAN ASPAL PORUS DENGAN PENAMBAHAN TREAD BAN BEKAS PADA UJI MARSHALL

AbstractTread Used Tires is a term waste from the component of the sole of an outer tire of a vehicle made of solid rubber structure. The waste is solid, not brittle (resilient) and resistant to water. From some of the definitions of the nature so that Tread used tires can be used as a media to increase the asphalt pavement component in the preparation of the following research.From the research that has been done with volumetric and Marshall parameters, asphalt pavement without the addition of used tire tread shows the calculation of VMA 17.44%, VIM 5.14%, VFB 67.27%, Stability 1217kg, Flow 3 mm, and MQ 434 kg / mm. The addition of 10% tire tread shows the calculation of VMA 16.1%, VIM 3.4%, VFB 64.82%, Stability 1145kg, Flow 3mm, and MQ 398 kg / mm. In testing the AC-BC mixture with the addition of used tire tread using the Marshall method, it was shown that the tread of used tires was suitable as an additive in porous asphalt mixes, it was based on the general specifications of Bina Marga 2010 Division 6 on road pavement.

All-in-one filler-elastomer-based high-performance stretchable piezoelectric nanogenerator for kinetic energy harvesting and self-powered motion monitoring

Flexible nanogenerators with advantages of conformal structure and easy assembly have become an appealing research field for wearable electronics recently. Here, an all-in-one filler-elastomer-based high-performance stretchable piezoelectric nanogenerator (SPENG) is reported. By mechanically shearing and uniformly dispersing high weight compositions of PZT particles and Ag-coated glass microspheres fillers into the identical solid state silicone rubber matrixes, the piezoelectric layer and electrode layers are prepared, respectively, and the SPENG can be fabricated in an all-in-one structure with tight adhesion and reliable durability, which is very important to the tension sensing and energy harvesting for the limb motion with large strain and variable degree of freedom. The stretchable energy harvester exhibits excellent output performances (Voc≈20 V, Isc≈0.55μA, 3.93μW/cm3) and can respond to different external stimulations (such as stretched, clustered, folded, twisted, etc.). The SPENG can be not only mounted on a joint to efficiently capture and convert random body kinetic energy into electricity as a power supply for portable electronics, but also used as the self-powered tension and gesture sensors to monitor dynamic motions. This work has demonstrated a great progress in stretchable electronics and energy harvesting technology, which may have important prospects in artificial intelligence and individualized medical care.

Thermo-mechanical coupling analysis of transient temperature and rolling resistance for solid rubber tire: Numerical simulation and experimental verification

The achievement of low rolling resistance and long-term durability of tires on various vehicles is of great challenge. Tire performances heavily depend on rubber properties; however, the thermo-mechanical coupling characteristics of rubber composites are complicated rendering the design of high-performance tires time-consuming and costly. In our research, the transient temperature and rolling resistance of a solid rubber tire were performed based on the thermo-mechanical coupling approach and nonlinear viscoelastic theory by using finite element method. Particular attention was paid to the strain cycles as the tire rolling on the road presents non-sinusoidal deformation. First, a static three dimensional tire-road contact analysis was conducted to obtain the principal strain cycles. Second, the 100th-order Fourier sine series was used to approximate the strain amplitude. Third, the heat generation rate proportional to the product of the loss modulus and the square of strain amplitude was calculated. The loss modulus was updated as a function of strain amplitude, temperature and frequency. Loss modulus softening effect was also considered. A practical method was proposed to compute the rolling resistance and transient temperature distributions by establishing a 2-D axisymmetric model. A rubber rolling tester was used to verify the numerical results. The comparison between numerical data and test data reveals that the proposed analytical method is a reliable approach to predict rolling resistance and transient temperature distribution for rubber tires. At last, the dependence of rolling resistance and heat build-up on thermal conductivity and loss factor were investigated by the parametric numerical experiments.

The Person Behind the Inventor of the Heart-Lung Machine: John H. Gibbon Jr, MD (1903-1973).

The Person Behind the Inventor of the Heart-Lung Machine: John H. Gibbon Jr, MD (1903-1973).

Viscoelastic and mechanical properties of large- and small-particle natural rubber before and after vulcanization

Insights into viscoelastic and mechanical properties of large- and small-particle natural rubber (NR) were gained for developing new rubber products. NR latex was first subjected to centrifuging to separate large rubber particles (LRP) and small rubber particles (SRP). The LRP and SRP solid rubbers were prepared to investigate their molecular weight characteristics and mechanical and viscoelastic properties. Before vulcanization, the LRP rubber was found to be better in both tensile strength and elasticity, as a result of natural branch-point networks formed by aggregation of phospholipid groups at the terminating end (α end) of the LRP rubber chains. After vulcanization, the SRP vulcanizate was, on the other hand, found to perform better in all respects. This could be explained by the accelerating effect from the proteins bound to the initiating end (ω end) of the SRP rubber chains in the crosslinking process during vulcanization.

Resistance of Laminated Veneer Lumber (LVL) Produced from Rubberwood, Radiata Pine and Larch Against Subterranean Termites And White Rot Fungi

Laminated veneer lumbers (LVLs) were fabricated using rubber wood, radiate pine and larch wood. Solid rubber wood was used to serve as control for comparison purpose. All of the wood samples were exposed to subterranean termites and white rot fungi for durability evaluation. The results showed that rubber wood LVL had the highest resistance against both deterioration agents in comparison to control, confirming that the resistance of non-durable wood species could be improved by converting them into LVL.

A model based method to determine rubber friction data based on rubber sample measurements

Abstract Rubber friction characteristics, which specify the sliding friction coefficient as a function of sliding speed, contact pressure etc., are required for tire models and have a substantial influence on their results. Classically, friction characteristics are determined based on sliding body measurements. In this paper, a new method is presented, which can be used to determine friction data for wet track conditions based on Grosch-wheel (solid rubber wheel) measurements. The aim is to represent more realistic contact conditions due to the rolling contact of such a wheel. When modeling tire characteristics, we show, that compared to friction characteristics obtained from sliding body measurements better results can be achieved by using the characteristics of the method mentioned in this paper.

Characterisation of cut and chip behaviour for NR, SBR and BR compounds with an instrumented laboratory device

ABSTRACTUnderstanding the cut and chip (CC) effect in rubber is important for successful product development for tires used in off-road or poor road conditions and for other demanding applications of rubber. This research describes a laboratory testing method for characterising the CC fracture behaviour of rubber using a device that controls and records multiple applied loads and displacements during cyclic impact to the surface of a solid rubber specimen to mimic and quantify the CC damage experienced by tire tread compounds. To study the capabilities of the instrument, three model compounds were studied that are based on carbon black reinforced compounds of common elastomers used in tire treads: natural rubber (NR), styrene-butadiene rubber (SBR), and butadiene rubber (BR). These polymers have well-established CC tendencies in field performance of tire treads, with NR exhibiting the best CC resistance followed by SBR and finally BR. The same trend was found with the rubber impact testing approach that allowed the CC behaviour to be quantified using a new physical parameter which is the CC propensity (P). The relative ranking for CC resistance for the three compounds followed the fatigue crack growth resistances of the materials but was exactly opposite to the ranking of DIN abrasion resistance. This provides evidence that CC damage from impact by mm-scale asperities and abrasion of rubber against μm-scale asperities exhibit distinct characteristics in rubber.

In vitro studies on the degradation of poly(cis-1,4-isoprene).

Cleavage of the backbone of poly(cis-1,4-isoprene) (IR) in solid rubber material was accomplished by the addition of partially purified latex clearing protein (Lcp1VH2 ) using a 200-mL enzyme reactor. Two strategies for the addition of Lcp1VH2 were studied revealing that the daily addition of 50 µgmL-1 of Lcp1VH2 for 5 days was clearly a more efficient regime in comparison to a one-time addition of 250 µg of Lcp1VH2 at the beginning. Soluble oligo(cis-1,4-isoprene) molecules occurred as degradation products and were identified by ESI-MS and GPC. Oxygenase activity of Lcp1VH2 with solid IR particles as substrate was shown for the first time by measuring the oxygen consumption in the reaction medium. A strong decrease of the dissolved oxygen concentration was detected at the end of the assay, which indicates an increase in the number of cleavage reactions. The oligo(cis-1,4-isoprene) molecules comprised 1 to 11 isoprene units and exhibited an average molecular weight (Mn ) of 885 gmol-1 . Isolation of the oligo(cis-1,4-isoprene) molecules was achieved by using silica gel column chromatography. The relative quantification of the isolated products was performed by HPLC-MS after derivatization with 2,4-dinitrophenilhydrazyne yielding a concentration of total degradation products of 1.62 gL-1 . Analysis of the polymer surface in samples incubated for 3 days with Lcp1VH2 via ATR-FTIR indicated the presence of carbonyl groups, which occurred upon the cleavage reaction. This study presents a cell-free bioprocess as an alternative rubber treatment that can be applied for the partial degradation of the polymer. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:890-899, 2018.