Rubber Technology is the subject dealing with the transformation of rubbers or

elastomer An elastomer is a polymer with viscoelasticity (i.e. both viscosity and Elasticity (physics), elasticity) and with weak intermolecular forces, generally low Young's modulus and high Deformation (mechanics), failure strain compared with other mate ...

s into useful products, such as

automobile A car or automobile is a motor vehicle with wheels. Most definitions of ''cars'' say that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people instead of goods. The year 1886 is regarded ...

tire A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a Rim (wheel), wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide Traction (engineering), t ...

s, rubber mats and, exercise rubber stretching bands. The materials includes

latex Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well. In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...

natural rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

synthetic rubber A synthetic rubber is an artificial elastomer. They are polymers synthesized from petroleum byproducts. About 32-million metric tons of rubbers are produced annually in the United States, and of that amount two thirds are synthetic. Synthetic rubb ...

and other polymeric materials, such as

thermoplastic elastomer Thermoplastic elastomers (TPE), sometimes referred to as thermoplastic rubbers, are a class of copolymers or a physical mix of polymers (usually a plastic and a rubber) that consist of materials with both thermoplastic and elastomeric properties. ...

s. Rubber processed through such methods are components of a wide range of items. Rubber products can be categorized into two main categories. * Dry rubber products (dry form) *

Latex Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well. In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...

(wet rubber) products (liquid form)

Vulcanization

Most rubber products are vulcanized, a process which involves heating with a small quantity of sulphur (or equivalent cross-linking agent) so as to stabilise the polymer chains, over a wide range of temperature. This discovery was made by

Charles Goodyear Charles Goodyear (December 29, 1800 – July 1, 1860) was an American self-taught chemist and manufacturing engineer who developed vulcanized rubber, for which he received patent number 3633 from the United States Patent Office on June 15, 1844. ...

in the 1844, but is a process restricted to polymer chains having a

Double bond In chemistry, a double bond is a covalent bond between two atoms involving four bonding electrons as opposed to two in a single bond. Double bonds occur most commonly between two carbon atoms, for example in alkenes. Many double bonds exist betwee ...

in the backbone. Such materials include

and

polybutadiene Polybutadiene utadiene rubber BRis a synthetic rubber. Polybutadiene rubber is a polymer formed from the polymerization of the monomer 1,3-butadiene. Polybutadiene has a high resistance to wear and is used especially in the manufacture of ti ...

. The range of materials available is much wider however, since all polymers become elastomeric above their

Glass transition The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or ru ...

temperature. However, the elastomeric state is unstable because chains can slip past one another resulting in

creep Creep, Creeps or CREEP may refer to: People * Creep, a creepy person Politics * Committee for the Re-Election of the President (CRP), mockingly abbreviated as CREEP, an fundraising organization for Richard Nixon's 1972 re-election campaign Art ...

or stress relaxation under static or dynamic load conditions. Chemical cross links add the stability to the network that is needed for most practical applications.

Processing of rubber

Methods for processing rubber include

mastication Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, ...

and various operations like mixing,

calendering Calendering of textiles is a finishing process used to smooth, coat, or thin a material. With textiles, fabric is passed between calender rollers at high temperatures and pressures. Calendering is used on fabrics such as moire to produce its wat ...

extrusion Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex c ...

, all processes being essential to bring crude rubber into a state suitable for shaping the final product. The former breaks down the polymer chains, and lowers their

molecular mass The molecular mass (''m'') is the mass of a given molecule: it is measured in daltons (Da or u). Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element. The related quant ...

so that

viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the int ...

is low enough for further processing. After this has been achieved, various additions can be made to the material ready for cross-linking. Rubber may be masticated on a two-roll mill or in an

industrial mixer In industrial process engineering, mixing is a unit operation that involves manipulation of a heterogeneous physical system with the intent to make it more homogeneous. Familiar examples include pumping of the water in a swimming pool to homogen ...

, which come in different types. Rubber is first compounded with additives like sulfur, carbon black and accelerators. It is converted into a dough-like mixture which is called "compound" then milled into sheets of desired thickness. Rubber may then be extruded or molded before being cured.

References

External links

Latex Technology - What Is Wet Rubber
{{Rubber Manufacturing Rubber products Rubber industry

Vulcanization

Processing of rubber

See also

References

External links