Engineering sciences mechanical properties of rubber an overview al. After the latex is processed, natural rubber becomes an elastomer with excellent mechanical properties. Some applications demand the most out of their individual parts. Products are formed from dry natural rubber by compression molding, extrusion, or by converting the sheets into a solution for dipping. These units are linked in a cis1,4configuration that gives natural rubber the outstanding properties of high resilience and strength. The rubber materials selected by designers and technical buyers should meet all their application requirements.
While polyisoprene can also be made synthetically, producing what is known as synthetic natural rubber. In natural rubber, most of the double fonds formed in the polymer chain have the z configuration, resulting in natural rubbers elastomer qualities. After all, the name olmec literally translates to rubber people. However, synthetic rubber is advantageous because it is easier to produce. Such abbreviations are used also in this paper for marking of the rubbers. Natural rubber is an elastomer constituted of isoprene units.
In addition to sporting purposes, natural rubber material was also used as a currency in their societies. Characteristic properties of silicone rubber compounds. Natural rubber exhibits unique and special chemical and physical properties and it is greatly influenced by the presence of non rubber substances thomas et al. It is extracted in the form of latex from the bark of the hevea tree. Nr is a polymer of cisisoprene units linked together at 14 positions. Rubber material selection guide nr or natural rubber. Mastication the rubber obtained from the tapping process is still not ready to. Natural rubber and synthetic rubber preparation and properties. Typically, a small percentage of other materials including proteins, fatty acids, resins, and inorganic materials are found in natural rubber. Rubber is unique in the extent to which it can be distorted, and the rapidity and degree.
Introduction to the manufacture of rubber products. Discovered in the early 1700s, natural rubber material was presented to the royal science academy of france as a valuable resource interest. Development work should be done at these temperatures, not your standard lab cure temperature of 320f or 340f. The olmecs were the earliest recorded users of natural or live rubber. Rubber, its history, properties, and applications dtic. It is extracted from the sap of the hevea brasiliensis tree grown in. Natural rubber is a good gasket material due to excellent physical properties. Overall, the combined properties of natural rubber outweigh synthetic rubbers or combinations of synthetic rubbers available. Natural rubber is the elastomer with the lowest heat buildup, making it unavoidable for dynamical applications with high strain and high frequencies such as tyres subjected to heavy strains. Natural and synthetic rubbers chemistry libretexts. Natural rubber is composed of the polymer polyisoprene. Natural rubber occurs as a latex water emulsion and is obtained from hevea. Nitrile has good mechanical properties and high wear resistance relative to other elastomers. Natural rubber is a crop able to grow only in tropical climates and it doesnt age well, so for many countries it is easier to use synthetic rubber.
Natural rubber is the only nonsynthetic rubber and has been in commercial use since the beginning of the 20th century. With little knowledge about the functions of this new. Crude natural rubber is found in the juices of many plants shrubs, vines, and trees, the principal of which is the hevea brasiliensis tree, native to brazil. A tough material for physically demanding applications. Natural rubber, natural rubber properties, natural rubber.
Natural rubber,treatments to improve and modify natural. The rubber is collected from the latex in a series of steps involving preservation, concentration, coagulation, dewatering, drying, cleaning, and blending. The importance of the rubber industry from the time it came into being and the role that it has played in the growth of civilization has been enormous. Properties of rubber elastomer properties custom advanced. Difference between natural and synthetic rubber compare. Common name neoprene natural polyisoprene butyl chlorinated butyl buna n sbr hypalon vamac ethylene propylene rubber polyethylene teflon crosslinked polyethylene modified crosslinked polyethylene composition name chlorprene. Types of rubber and basic properties all seals inc.
Crack propagation in an aged and unaged natural rubber vulcanizate was measured using a double cantilever beam, dcb. Current global status of production and consumption. Bulletin of the transilvania university of bra sov vol. However, the knowledge of rubbers physical properties and their measurement is critical for compound selection. They typically reach 2030 metres in height on rubber plantations, and are able to produce commercial quantities of latex at about 7 years of age, depending on climate and location. It has excellent green strength and tack which means that it has the ability to stick to itself and to other materials which makes it easier to fabricate. Martins rubber explain the advantages of natural rubber. Pdf study on the properties of natural rubber during maturation. Charles goodyear accidentally discovered that by mixing sulfur and rubber, the properties of the rubber improved in being tougher, resistant to heat and cold, and increased in elasticity. It was shown that both the elastic responses and viscosity change with amplitude of oscillation and with concentration and type of carbon black. Synthetic rubber is easier to produce than natural rubber, and has a wider range of applications. Physical properties of rubber a buyer and designers guide. Both natural rubber and synthetic rubber ir have high tear resistance, good low temperature flexibility, and high tensile strength. Pdf structure and properties of natural rubberbutadiene.
The collected latex is washed, filtered and reacted with acids to congeal the rubber particles. The only drawback that these sheets have is that they are not. Since many compounders have been schooled in rubber chemistry while working with natural rubber formulas, there is usually a certain comfort level with natural rubber. Chemistry, manufacture and applications of natural rubber. The properties and characteristics of manufactured rubber products may vary based on polymer type and formulation. Its resistance to solvents and petroleum products is about the same as natural rubber.
The chemical structure of natural rubber is cis1,4polyisoprene, but the exact structure of the head and end groups remains. There are 5 mechanical properties of natural rubber that have transcended time. Properties, behavior and uses natural rubber nr is the most often used rubber in the industry. Structure and properties of natural rubberbutadiene rubber nrbr blendsodium montmorillonite nanocomposites prepared via a combined latexmelt intercalation. Please note that information presented here is general to natural rubber polymer.
Natural rubber properties advantages of natural rubber. The work examined both the quasistatic and dynamic mechanical properties of two natural rubber vulcanizates, which had been subjected to isothermal anaerobic aging. Mechanical properties and durability of natural rubber. Mechanical properties and crosslinking structure of cross. Natural rubber has certain unique properties such as follows. As such, natural rubber and synthetic polyisoprene share many similarities in physical properties.
The inherent physical characteristics of elastomers can be modified through compounding. Several studies have been carried out to reuse scraptires in a variety of rubber and plastic products, incineration for production of electricity. Properties of natural rubber reinforced by carbon blackbased hybrid fillers. Natural rubber has superior resilience, tensile, elongation and abrasion resistance, good low temperature flexibility and compression set and excellent adhesion to fabric and metals. An advantage natural rubber has over synthetic rubber is that natural rubber. Being one of the best natural rubber sheet suppliers our sheets are also highly resistant to salts, acids, alkalis and water. The dynamic properties of a natural vulcanized rubber containing carbon black were studied for dynamic tensions of amplitude varying greatly. Mechanical properties and durability of natural rubber compounds. This sciencestruck article gives you a comparison between synthetic rubber and natural rubber. Pdf spontaneous coagulation nr, acid coagulation nr and constant viscidity nr were prepared and their properties were studied. Difference between natural rubber and synthetic rubber. Rubber tapping the milky white liquid latex is collected from the rubber trees in a cup by making a slight vcut on the tree bark. Natural rubber comes from the havea brasiliensis tree, which grows in tropical regions.
Pdf properties of natural rubber reinforced by carbon. Natural rubber vs synthetic rubber coi rubber products. The fine properties of silicone rubber 15 2 meeting the increasingly diverse and sophisticated needs of industry with the unique properties of silicone rubbers the main ingredients of shinetsus silicone rubber compounds are unique raw silicone rubber gum and highpurity silica. Natural rubber combines high strength tensile and tear with outstanding resistance to fatigue.
Dry natural rubber this is rubber produced by the dry natural rubber dnr process, which involves the use of coagulated natural latex in the form of dried or milled sheets. The difference between latex, natural rubber, natural. Our natural rubber sheet is produced by blending natural and synthetic rubber. Rubber properties, rubber mechanical properties, oring. Our rubber products are a proprietary blend of various polymers formulated to. Natural rubber is a versatile material use in engineering for many years because it can take a beating and still perform crucial functions.
Without special additives, it is vulnerable to ozone, oxygen and sunlight. Generally, black in color, they exhibit excellent physical properties such as high mechanical strength and tear resistance. Unless they are specially compounded, nitrile is not resistant to weathering, sunlight and ozone. There are at least 2,500 different latexproducing plant species. Elasticity is one of the fundamentally important properties of natural rubber.