scholarly journals The Effect of Thermal Ageing on the Mechanical Properties of Natural Rubber-based Compounds Used for Rubber Bearings

2021 ◽  
Vol 53 (3) ◽  
pp. 210310
Author(s):  
Manuel Alberto Guzmán ◽  
Diego Hernán Giraldo-Vásquez ◽  
Ricardo Moreno
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Standardized Tests ◽  
Oxidative Degradation ◽  
Hardness Test ◽  
Thermal Ageing ◽  
Design Standards ◽  
Rubber Compounds ◽  
Allowable Compressive Stress ◽  
Rubber Bearings

Molecular changes due to high temperatures, sunlight, and oxygen, deteriorate the physical properties of rubber compounds, yielding additional crosslinks and molecular chain breakdown. Since oxidative degradation is the most important factor that determines the durability of rubber components, this study evaluated the mechanical behavior of rubber compounds exposed to accelerated thermal ageing. Therefore, three carbon black-reinforced natural rubber-based compounds typically used for rubber bearings were exposed to thermal oxidation and their mechanical properties under typical loading states were assessed through standardized tests. Significant differences were found due to thermal ageing in the compressive modulus, compression set, and creep compliance in compression, exhibiting a stiffening effect caused by additional crosslinks. However, no significant differences were observed in hardness, which is a superficial measurement and a typical test in the rubber industry to characterize rubber compounds. Therefore, the assessment of ageing in rubber bearings should not be limited to a hardness test, which is required in design standards but also addresses compressive, cyclic, and transient tests. The results obtained in this study can be considered in the design process of rubber bearings by limiting the allowable compressive stress and creep deflection due to ageing effects.

Calophyllum Inophyllum Oil as Plasticizer in Natural Rubber Compounds

2009 ◽  
Vol 25 (2) ◽  
pp. 113-128 ◽  
Author(s):  
P. Raju ◽  
V. Nandanan ◽  
Sunil K.N. Kutty
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Thermal Studies ◽  
Calophyllum Inophyllum ◽  
Compression Set ◽  
Peak Rate ◽  
Rubber Compounds ◽  
Cure Time ◽  
Calophyllum Inophyllum Oil ◽  
Control Compound

Mechanical properties and the thermal degradation characteristics of natural rubber compounds with calophyllum inophyllum oil were compared to that of the control compound containing naphthenic oil. The compounds containing calophyllum inophyllum oil showed improved tensile strength, tear strength, modulus, compression set, abrasion resistance and resilience. Cure time was higher than the naphthenic oil mixes. Thermal studies showed an increase of 8 °C in the temperature of initiation of degradation and an increase of 6 °C in temperature at which the peak rate of degradation occurred. The peak rate of degradation was comparable to the control mix containing naphthenic oil.

Characterization of Snap-On Calf Nipple Product and Development of its Compound Formulation Based on Natural Rubber

2017 ◽  
Vol 744 ◽  
pp. 282-287
Author(s):  
Sarawut Prasertsri ◽  
Sansanee Srichan
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Calcium Carbonate ◽  
Carbon Black ◽  
Natural Rubber ◽  
Soxhlet Extraction ◽  
Rubber Compound ◽  
Rubber Compounds ◽  
Rubber Component

This research aimed to develop the formulation of natural rubber filled with carbon black, silica and calcium carbonate for rubber calf nipple application. The reverse engineering was performed on the calf nipple product to analyze the rubber type and component by using Soxhlet extraction, thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) techniques. Furthermore, mechanical properties were examined to act as benchmark for the rubber compound design. The results showed that rubber component in the nipple product was natural rubber, whereas two filler types revealed as carbon black and calcium carbonate with 10 and 35 of the total weight. In addition, rubber nipple showed the hardness of 46±1 Shore A and tensile strength of 5.3±0.60 MPa. From the investigation of the properties of developed rubber compounds in this work, it was found that the mechanical properties depended on type and content of filler. The required mechanical properties of vulcanizates were achieved at 20 phr of carbon black (N330), 20 phr of silica and 120 phr of calcium carbonate.

A Review on Heat and Reversion Resistance Compounding

2003 ◽  
Vol 19 (3) ◽  
pp. 143-170 ◽  
Author(s):  
R. N. Datta
Keyword(s):  
Thermal Stability ◽  
Natural Rubber ◽  
Physical Properties ◽  
Dynamic Performance ◽  
Thermal Ageing ◽  
Vital Role ◽  
Performance Characteristics ◽  
Network Density ◽  
Performance Property ◽  
Rubber Compounds

When sulfur vulcanized natural rubber compounds are exposed to a thermal ageing environment significant change in physical properties and performance characteristics are observed. These changes are directly related to modifications of the original crosslink structure. Decomposition reactions tend to predominate and thus leading to reduction in crosslink density and physical properties as observed during extended cure and when using higher curing temperatures. The decrease in network density is common when vulcanizates are subject to an anaerobic ageing process. However, in the presence of oxygen, the network density is increased with the main chain modifications playing a vital role. Over the years the rubber industry has developed several compounding approaches to address the changes in crosslink structure during thermal ageing. This paper gives a review of these compounding approaches. As with many formulation changes in rubber compounding, there is a compromise that must be made when attempting to improve one performance characteristic. For example, improving the thermal stability of vulcanized natural rubber compounds by reducing the sulfur content of the crosslink through the use of the more efficient vulcanization systems will reduce dynamic performance property such as fatigue resistance. The challenge is to define a way to improve thermal stability while maintaining dynamic performance characteristics.

HXNBR Coating for Improving Aging Resistance of Natural Rubber Products

2006 ◽  
Vol 79 (4) ◽  
pp. 553-560 ◽  
Author(s):  
Rani Joseph
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Room Temperature ◽  
Oxidative Degradation ◽  
Thin Coating ◽  
Oil Resistance ◽  
Aging Resistance ◽  
Natural Rubber Vulcanizates ◽  
Good Heat ◽  
Accelerator System

Abstract HXNBR (Hydrogenated Carboxylated Nitrile Rubber) has very good heat ageing resistance and oil resistance. A novel accelerator system is designed to bring about the vulcanization of HXNBR at room temperature. The room temperature cured samples showed good mechanical properties equivalent to those of high (150 °C) temperature cured samples. Natural rubber vulcanizates are highly prone to oxidative and ozone degradation. The oil resistance of natural rubber vulcanizates is also very low. The oil resistance, ozone and oxidative degradation resistance of natural rubber vulcanizates are considerably improved by placing a thin coating of HXNBR over it.

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

2016 ◽  
Vol 4 (10) ◽  
pp. 5258-5267 ◽  
Author(s):  
Davide Barana ◽  
Syed Danish Ali ◽  
Anika Salanti ◽  
Marco Orlandi ◽  
Luca Castellani ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Natural Rubber ◽  
Rubber Compounds

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

2020 ◽  
Vol 1428 ◽  
pp. 012020
Author(s):  
N. Bukit ◽  
E.M. Ginting ◽  
E. Sidebang ◽  
E. Frida ◽  
B.F. Bukit
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Natural Rubber ◽  
Oil Palm ◽  
Rubber Compounds ◽  
Boiler Ash

A Review of Rubber Oxidation

2005 ◽  
Vol 78 (2) ◽  
pp. 355-390 ◽  
Author(s):  
Gui-Yang Li ◽  
J. L. Koenig
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Spatial Distribution ◽  
Oxidative Degradation ◽  
Physical And Mechanical Properties ◽  
Oxidation Products ◽  
Unique Combination ◽  
The Past ◽  
Diffusion Limited ◽  
Rubber Compounds

Abstract The aging of rubber caused by oxidative degradation leads to the deterioration in the physical and mechanical properties of vulcanized rubbers. In an effort to improve the oxidative stability of rubbers and elastomers, considerable amount of work has been carried out over the past 50 years (especially in the most recent 5 years) in order to understand degradation modes and effects in rubber due to the action of oxygen and ozone in the air. Different mechanisms have been proposed to interpret the experimental data relative to the oxidation of rubber. The diffusion limited theory has been widely used in the literature and verified by many experiments. Various instrumental techniques have been utilized to characterize the oxidation and degradation and their mechanisms in rubber compounds. Recently, FTIR imaging has demonstrated a unique combination of spectral and spatial resolution which allows not only the identification of the oxidation products but also their spatial distribution from the oxygen penetrating surfaces. This critical review will cover the major developments in our understanding of the oxidation of rubbers.

Cure Characteristic and Mechanical Properties of Epoxidized Natural Rubber/Chloroprene (ENR/CR) Blends

2010 ◽  
Vol 93-94 ◽  
pp. 631-634
Author(s):  
Chanchai Thongpin ◽  
Piyaporn Niltui ◽  
Piyapong Sornwaneenawakhun ◽  
Tossaporn Maneeprom ◽  
Saovaros Malithong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Epoxidized Natural Rubber ◽  
Maximum Torque ◽  
Tear Strength ◽  
Rubber Compounds ◽  
Cure Time ◽  
Chloroprene Rubber ◽  
Cure Characteristic ◽  
Two Phases

Epoxidized Natural rubber (ENR) with the epoxide content of 40 % was prepared and blended with various contents of chloroprene rubber (CR) and 50 phr of carbon black. The cure characteristic, mechanical properties and the effect of gasohol E-85 on the mechanical properties of the rubber vulcanizate were studied. It was revealed from cure characteristic results, tested by Moving Die Rheometer (MDR), that minimum torque of the rubber compounds increased with the content of CR whereas maximum torque tended to increase at the content of 10 phr and decrease after this content, of which the values agreed well with the modulus at 100% elongation in rubber vulcanizates. Considering characteristic scorch and cure time, the values increased with the CR contents. It was clear from the result that at the ENR:CR ratio of 90:10, modulus of 100% elongation and tear strength exhibited the highest values. It was also found that the mechanical properties of the blend vulcanizates were slightly suffered by gasohol E85 except for tear strength. It was understood that this must be because of the effect of the phase continuity and crosslinking that occurred differently in two phases. The phase morphology of the blends were also investigated and reported in the research.

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