Properties Of Natural Rubber Compounds Research Articles

Correlations between lipid contents of natural rubber and tensile properties of natural rubber-based compound, using attenuated total reflection Fourier transform infrared spectroscopy

In this study, the lipid contents of different kinds of natural rubber were measured by attenuated total reflection–Fourier transform infrared spectroscopy. The correlation between these amounts were considered with the tensile properties of natural rubber compounds. The Pearson correlation coefficients were more than −0.9 for all cases, which confirms that the models are acceptable. These models were applied for the estimation of tensile properties in the case study. It was observed that the tensile strength, elongation at break, modulus 100%, and modulus 300% can be predicted by errors of about 4%, 17%, 18%, and 18% respectively. This is a simple, fast, and nondestructive way to estimate the tensile properties before the compound preparation.

Correlation between the Crosslink Characteristics and Mechanical Properties of Natural Rubber Compound via Accelerators and Reinforcement.

The extreme elasticity and reversible deformability of rubber, which is one of the most versatile polymers in modern society, is dependent on several factors, including the processing conditions, curing system, and types of additives used. Since the rubber’s mechanical properties are influenced by the existing structural crosslinks, their correlation with the crosslink characteristics of rubber was investigated using the equilibrium swelling theory of the Flory–Rehner equation and the rubber–filler interaction theory of the Kraus equation. Herein, we examined whether the accelerator and reinforcement agent quantitatively contributed to chemical cross-linkages and rubber–filler interaction. In conclusion, the accelerator content supported the chemically crosslinked structures of the monosulfides and the disulfides in natural rubber (NR). Additionally, these results demonstrated that the mechanical properties and the thermal resistance of NR were dependent on the crosslink characteristics. The findings of this study provide an insight into the development and application of NR products for the mechanical optimization of rubber-based products.

Mechanical Properties of Natural Rubber Compounds with Oil palm boiler ash and Carbon Black as a Filler

This study aims to determine the mechanical properties of natural rubber compounds with variations of OPBA nanoparticle fillers and carbon black. Preparation methods for natural rubber compounds using Open Mill. Indonesian rubber standard -20 (SIR-20) mixed with anti-oxidants, activators, curing agents, accelerators and OPBA nanoparticle fillers size 56.31 nm and commercial Carbon black type (N330) with variations (0,2,4,6 and 8)% wt. The results showed that tensile strength increased with the increase in the composition of OPBA nanoparticles and carbon black, as well as the elongation of break and hardness. The best composition of OPBA filler 8% wt showed a hardness of 52 Shore A, a tensile strength of 1.7 MPa, an elongation of break 150%. The best composition of carbon black 8% wt filler with a hardness of 55 Shore A, a tensile strength of 2.5 MPa, elongation breakdown of 140%.

Effect of nitrosamine safe diisopropyl xanthogen polysulfide accelerator on cure and static mechanical properties of natural rubber compounds

Sulfur vulcanization of natural rubber (NR) is mainly carried out with the use of accelerators in order to achieve desired network structure and consequently the specific material properties. Many traditional organic accelerators are made from secondary amines and are capable of nitrosation during and after vulcanization in the presence of nitrosating agents. Therefore, the use of most of the nitrosamine generating traditional accelerators in rubber formulations are restricted by stringent rules and regulations imposed by world environmental and health-related government agencies. Diisopropyl Xanthogen Polysulfide (DIXP) has been identified as a nitrosamine safe novel accelerator and literature on use of this accelerator in natural rubber compounds is limited. The aim of this study was to evaluate the influence of DIXP on cure and static mechanical properties of NR compounds. A series of NR compounds was prepared with DIXP by varying the accelerator dosage from 0.2 phr to 2.2 phr at 0.4 phr intervals. Cure and static mechanical properties of the compounds were evaluated and compared with those of the compounds prepared with the commonly used nitrosamine safe N-tert-butyl-2-benzothiazole sulfenamide (TBBS) accelerator. Results showed that most of the properties of NR compounds prepared with DIXP are inferior in comparison to those of the compounds prepared with TBBS. Nevertheless, NR compounds prepared with DIXP possessed satisfactory results in regard to optimum cure time and elongation at break.

Microstructure and thermal properties of natural rubber compound with palm oil boilers ash for nanoparticle filler

This study aims to determine the properties of natural rubber compounds by varying the Oil Palm Boiler Ash (OPBA) nanoparticles with variations (0,2,4,6 and 8) wt%. The preparation method for natural rubber compounds uses Open Mill by mixing Indonesian Rubber Standard-20 (SIR-20) with anti-oxidants, activators, preservatives, accelerators, and OPBA nanoparticle fillers. The results showed thermal properties with Differential Scanning Calorimetric (DSC) increased melting point and the presence of cross bonds with increasing OPBA composition compared without filler. The distribution of compounds occurs even with the addition of OPBA filler. The results of the XRD diffraction pattern analysis of natural rubber composites without fillers amorphously shaped, but with the addition of OPBA fillers, the diffraction pattern showed a crystal structure. The FTIR graph shows that there is no significant difference between compounds with and without fillers.

Influence of Activated Rubber Powder on the Mechanical Properties of Natural Rubber Compound

Influence of Activated Rubber Powder on the Mechanical Properties of Natural Rubber Compound

Optimizing Properties of Natural Rubber Compounds Using Tetrabutylammonium bis(N‐phenylsulfonyldithiocarbimate)zincate(II) as Accelerator

The rheometric properties of natural rubber compounds containing the compound tetrabutylammonium bis(N‐phenylsulfonyldithiocarbimate)zincate(II) as the accelerator are modulated by means of the response surface methodology (RSM), where the Face Centred Central Composite Design (FCCD) with three factors and three levels was chosen with the objective to obtain the relationship among the evaluated properties and factor levels. The factors in the experimental design are the amounts of both accelerator and sulfur and the vulcanization temperature. The compounds are evaluated as for the scorch time, optimum vulcanization time, and maximum torque. For each of these properties the Regression analysis, the pareto diagram and the fitted surface are obtained. Concerning the scorch and optimum vulcanization times, the most important factors are the vulcanization temperature and the amount of accelerator, respectively. Regarding the maximum torque, the most significant factors are the amounts of sulfur and accelerator. Considering the optimum vulcanization time a regression model with good accuracy could be obtained. The function desirability is used to obtain an optimum condition for an adequate cure system related to a set of desired intervals for the properties of interest.

The effect of high purity rice husk silica synthesised using solvent-thermal extraction method on the properties of natural rubber compounds

This work highlights the synthesis of high purity silica from rice husks and the effect of rice husk silica (RHS) loading on the mechanical, physical, and thermal properties of natural rubber (NR) compounds. The RHS was synthesised using the solvent-thermal extraction method, which was adopted from TAPPI T204 (2007) and TAPPI T264 (1997) standards with some modifications. The treatment successfully produced high purity RHS particles, with 99.9% SiO2 content between 100 to 300 nm in size. The high purity RHS was then incorporated in NR compounds at 2, 4, 6, 8, and 10 parts per hundred rubber (phr). Even without any surface modification, the high purity RHS-filled NR compounds showed tremendous improvements in strength-related properties at the optimum loading of 4 phr. In addition, the thermal stability of the NR compounds was remarkably improved with the addition of RHS.

Studies on cure index, swelling behaviour, tensile and thermooxidative properties of natural rubber compounds in the presence of alkanolamide

The studies on cure index, swelling behaviour, tensile and thermo-oxidative properties of unfilled natural rubber (NR) compounds in the presence of alkanolamide (ALK) were carried out. As a rubber additive, the ALK was added into the NR compounds at various loadings (0.2, 0.4, 0.6, 0.8, and 1.0 phr). It was found that the cure indexes of NR compounds with ALK were higher than that of NR compound without ALK (control compound). It was also found that ALK exhibited higher tensile modulus and tensile strength up to 0.6 phr of loading and then decreased with further increases in the loading. The swelling test revealed that 0.6 phr of ALK in the unfilled NR compound exhibited the highest degree of crosslink density which correlated to the highest tensile modulus and tensile strength of the NR vulcanisates. The ALK increased the heat aging resistance of the NR vulcanisates.

Effect of Butylamine Modified Kenaf Fibre on the Properties of Natural Rubber Compounds and Vulcanizates

Filled compound prepared via typical rubber compounding or wet masterbatch method. Wet masterbatch prepared by mixing a filler dispersion in a latex. Filler dispersion stability is crucial, and a stable dispersion is hypothesized to result in lower filler structure and subsequently better reinforcement of the filled vulcanizate. Stable dispersion has greater repulsive forces among the particles. In this study, kenaf fiber (KF) will be dispersed in a polar medium; i.e. butylamine. The dispersion stability and KF particle size with respect to the ball milling time shows longer ball milling time results in finer KF particle size due to higher surface charges from butylamine. Zeta potential concluded that the dispersions are stable. The masterbatches of KF then compounded using two-roll mill to incorporate curatives and anti-degradants. The results showed longer scorch and cure time were reported with the ball milling time. This might be due to higher hydroxyl groups from KF. The decrement of maximum and delta torque with ball milling time is correlated with crosslinked density. Better tensile strength, elongation at break, tear resistance and abrasion resistance were reported with longer ball milling time. Ball milling time does not affect the stiffness and hardness of the filled vulcanizates. By comparing the filled vulcanizates prepared from wet masterbatch and typical rubber compounding method, the former has better reinforcement but lower crosslink density and less stiff, longer scorch time and cure time

Characterization of Leather Wastes from Chrome Tanning and its Effect as Filler on the Rheometric Properties of Natural Rubber Compounds

Chrome tanning generates large amounts of leather wastes (LW) which have become a considerable environmental issue. In this work, particulate LW with and without urea treatment were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) under inert and oxidative atmospheres, and elemental analysis. Then treated LW (TLW) were incorporated in natural rubber compounds, seeking to find another way of disposal for this type of residue. The effect of TLW on rheometric properties of rubber composites during vulcanization was evaluated, including parameters related to leather particles dispersion in the matrix. It was found that TLW contained chromium and sulfur remaining from tanning, which could affect the properties of rubber compounds. During TGA analysis, oxidation of chromium into LW was increased as an effect of urea treatment. It was observed that TLW improved rubber processability during open two-roll mill mixing process. Rheometric characteristics allowed to identify a decreased TLW particle dispersion into the compound with the increase of its content in the composites. Stiffness of vulcanized composites and the kinetic of the vulcanization varied with TLW content, as an effect of the interaction of TLW with the rubber compound. Particulate leather wastes morphology could facilitate its mechanical interlocking with the polymeric matrix. The development of these type of composites will enable another profitable use for this type of waste.

Influence of Lignin Features on Thermal Stability and Mechanical Properties of Natural Rubber Compounds

The aim of this work is to elucidate the relationship between lignin main features and its behavior in natural rubber compounds, in particular focusing on thermal stability and mechanical properties. Five lignins obtained from different sources and through different extraction processes were characterized in terms of purity, sulfur content, molecular weight distribution (GPC), and qualitative and quantitative functional group distribution (FTIR and 31P NMR). Then, the lignins were incorporated in natural rubber by two different approaches, namely coprecipitation and dry-mixing. Thermal stability and mechanical properties of lignin/natural rubber blends were investigated in both masterbatches and vulcanized compounds. The oxidation induction time (OIT) was used to determine the thermal stabilization of the lignin/NR masterbatchs, while tensile stress–strain properties of the compounds were evaluated after vulcanization. It was found that differences in the chemical and morphological characteristics of lign...

미분쇄 탄소섬유와 카본블랙으로 강화된 천연고무 컴파운드의 기계적 특성

미분쇄 탄소섬유와 카본블랙으로 강화된 천연고무 컴파운드의 기계적 특성

Improving the Tensile Properties of Natural Rubber Compounds Containing Ground Ethylene Propylene Diene Rubber Waste by Two-stage Processing

This article describes concerning to the effect of different processing routes on the tensile properties of natural rubber compounds containing ground ethylene propylene diene rubber (EPDM) waste. Two-stage processing was promoted and compared with the conventional processing. The proposed processing was done by mixing ground EPDM waste, a dispersion form of rubber additives and natural rubber latex (NRL) prior to compound with the remaining dry rubber on the two-roll mill. By applying such method, the cross-linking distribution was significantly improved, providing the superior state of cure, cross-link density and tensile properties.

Effects of accelerators on the cure characteristics and mechanical properties of natural rubber compounds

The effects of different accelerators on the cure characteristics and mechanical properties of sulphur-cured natural rubber (NR)-based compounds are investigated. Three accelerator systems, with mercaptobenzothiazole disulphide (MBTS) as primary accelerator and diphenylguanidine (DPG) and Zn-2-mercaptobenzothiazole (ZMBT) as secondary accelerators, were incorporated into a premixed NR compound referred to an industrially used rubber mat formulation by using the melt mixing method. The cure characteristics, rubber crosslink density and mechanical properties were the focus in the present study. It is observed that the synergistic effect of the MBTS/DPG combination imparts the shortest scorch time, highest cure rate and highest crosslink density compared with the MBTS/ZMBT and MBTS/ZMBT/DPG combinations. Mechanical tests indicate that the tensile strength and modulus of MBTS/DPG are enhanced owing to improved cure activation in initiating sulphuric crosslinking, but the tear strength is decreased compared with the others. This study demonstrates that the MBTS/ZMBT/DPG system is the most effective in enhancing tear strength by 4.5 % compared with MBTS/DPG system, as well as other mechanical properties. Analyses on tear behaviours and scanning electron microscope (SEM) micrographs of the fractured surfaces of tear test samples correspond well with the results of tear strength.

Mechanical and rheological properties of natural rubber compounds containing devulcanized ground tire rubber from several methods

In the recent past we reported the investigation of different devulcanization processes of a ground tire rubber (GTR) such as supercritical fluid, ultrasonic and biological technologies. Each of these techniques had been previously optimized, focusing on the experimental combination of parameters providing the best devulcanization conditions. The present study aims to extensively compare the optimal conditions of these three different techniques for the devulcanization of a GTR. In particular the GTR and the devulcanizates by each technique were blended into raw natural rubber at a concentration of 10 phr. The rheological and mechanical properties of their vulcanizates were investigated and compared to find out the rubber providing the highest compatibility for compounding and revulcanization. In addition, a comparison of these results was made with the ones of raw natural rubber compound and vulcanizate.

Influence of Carbon Black and Silica Filler on the Rheological and Mechanical Properties of Natural Rubber Compound

Rubber compounds are reinforced with fillers such as carbon black and silica. In general, filled rubber compounds shows smooth rheological behavior and mechanical properties. Variation in rheological behavior and mechanical properties was studied in terms of the filler composition using natural rubber compounds filled with both carbon black and silica CB/Si = 0/60, 20/40, 30/30, 40/20 and 60/0 phr (parts per hundred rubber is parts of any non-rubbery material per hundred parts of raw gum elastomer (rubbery material)). The rheological behaviour can be showed in measurement of Mooney viscosity and cure time. The Mooney viscosity of rubber compounds increase with the increasing the carbon black in the compounds. The compound filled with CB/Si of 30/30 and 60/0 showed abnormal rheological behaviour in which the cure time decreased suddenly and the increased at certain ratio during the measurement. The mechanical properties such as hardness, abrasion resistance and tensile stress at 300% elongation were studied. In the hardness and abrasion resistance measurement, the higher ratio CB/Si decrease contribution of silica, which resulting smaller of hardness value. Ratio CB/Si 40/20 gives an optimum filler blended. It is also clearly understood that higher abrasion resistance mainly due to the lower hardness value under the same condition. The tensile stress at 300% elongation of rubber compound increased with the increasing carbon black filler.

Curing Characteristics and Tensile Properties of White Fly Ash Filled Natural Rubber Compounds

The effect of white fly ash (WFA) on cure characteristics and tensile properties of natural rubber compounds were investigated in the range of 0 to 30 phr. The size of WFA that is used in this study was 45-75 μm. Based on the result, it is found that the scorch time and cure time decreased with increasing of WFA loading. The tensile strength gradually increased to the maximum at 5 phr WFA. The further increase of WFA loading led to the decrease in tensile strength. Tensile properties such as M100 (stress at 100 % elongation) was gradually increased with the increasing of WFA loading, meanwhile, the elongation break showed a decreasing trend.

Alkanolamide as an accelerator, filler-dispersant and a plasticizer in silica-filled natural rubber compounds

A feasibility study was carried out on the utilization of Alkanolamide (ALK) on silica reinforcement of natural rubber (NR) by using a semi-efficient cure system. The ALK was incorporated into the NR compound at 1.0, 3.0, 5.0, 7.0 and 9.0 phr. An investigation was carried out to examine the effect of ALK on the cure characteristics and properties of NR compounds. It was found that ALK gave shorter scorch and cure times for silica-filled NR compounds. ALK also exhibited higher torque differences, tensile modulus, tensile strength, hardness and crosslink density of up to 5.0 phr of ALK loading, and then decreased with further increases of ALK loading. The resilience increased with increased ALK loading. Scanning electron microscopy (SEM) micrographs proved that 5.0 phr of ALK in the silica-filled NR compound exhibited the greatest matrix tearing line and surface roughness due to higher reinforcement level of the silica, as well as better dispersion and cure enhancement.

Study on Properties of Natural Rubber Compound Using Starch as Filler

Study on Properties of Natural Rubber Compound Using Starch as Filler