Ebonite

Last updated
Ebonite applications from the 19th century Ebonit.JPG
Ebonite applications from the 19th century

Ebonite is a brand name for a material generically known as hard rubber or vulcanite, obtained via vulcanizing natural rubber for prolonged periods. Ebonite may contain from 25% to 80% sulfur and linseed oil. [1] [2] Its name comes from its intended use as an artificial substitute for ebony wood. The material has also been called vulcanite, [3] although that name formally refers to the mineral vulcanite.

Contents

Charles Goodyear's brother, Nelson Goodyear, experimented with the chemistry of ebonite composites. In 1851, he used zinc oxide as a filler. [4] Hugh Silver was responsible for giving it its name. [5]

Properties

Schematic presentation of two strands (blue and green) of natural rubber after vulcanization with elemental sulfur Vulcanization of POLYIsoprene V.2.png
Schematic presentation of two strands (blue and green) of natural rubber after vulcanization with elemental sulfur

The sulfur percentage and the applied temperatures and duration of vulcanizing are the main variables that determine the technical properties of the hard rubber polysulfide elastomer. The occurring reaction is basically addition of sulfur at the double bonds, forming intramolecular ring structures, so a large portion of the sulfur is highly cross-linked in the form of intramolecular addition. As a result of having a maximum sulfur content up to 40%, it may be used to resist swelling and minimize dielectric loss. The strongest mechanical properties and greatest heat resistance is obtained with sulfur contents around 35% while the highest impact strength can be obtained with a lower sulfur content of 30%. The rigidity of hard rubber at room temperature is attributed to the van der Waals forces between the intramolecular sulfur atoms. Raising the temperature gradually increases the molecular vibrations that overcome the van der Waals forces making it elastic. Hard rubber has a content mixture dependent density around 1.1 to 1.2. When reheated hard rubber exhibits shape-memory effect and can be fairly easily reshaped within certain limits. Depending on the sulfur percentage hard rubber has a thermoplastic transition or softening temperature of 70 to 80 °C (158 to 176 °F).

The material is brittle, which produces problems in its use in battery cases for example, where the integrity of the case is vital to prevent leakage of sulfuric acid. It has now been generally replaced by carbon black-filled polypropylene.

Ultraviolet and daylight exposure

Under the influence of the ultraviolet portion of daylight, hard rubber oxidizes. Subsequent exposure to moisture bonds water with free sulfur on the surface, creating sulfates and sulfuric acid at the surface that are very hygroscopic. The sulfates condense water from the air, forming a hydrophilic film with favorable wettability characteristics on the surface. [6] These aging processes will gradually discolor the surface grayish green to brown and cause rapid deterioration of electric surface resistivity.

Contamination

Contaminated ebonite was problematic when it was used for electronics. During manufacturing the ebonite was rolled between metal foil sheets, which were peeled off, leaving traces of metal behind. For electronic use the surface was ground to remove these metal particles. [7]

Applications

Green/black rippled ebonite fountain pen made in 2014 and black ebonite fountain pen made in 2017 Gama Supreme & ASA Maya 1.jpg
Green/black rippled ebonite fountain pen made in 2014 and black ebonite fountain pen made in 2017

Hard rubber was used in early 20th century bowling balls; however, it was phased out in favor of other materials (the Ebonite name remains as a trade name for one of the major manufacturers of polymer balls). [8] It has been used in electric plugs, tobacco pipe mouthpieces (in competition with Lucite), fishing reels, hockey pucks, fountain pen [9] [10] bodies and nib feeds, saxophone and clarinet mouthpieces, as well as complete humidity-stable clarinets. [11] [ better source needed ] Hard rubber is often seen as the wheel material in casters. It is also commonly used in physics classrooms to demonstrate static electricity, because it is at or near the negative end of the triboelectric series.[ citation needed ]

Hard rubber was used in the cases of automobile batteries for years, thus establishing black as their traditional colour even long after stronger modern plastics like polypropylene were substituted. It was used for decades in hair combs made by Ace, now part of Newell Rubbermaid, although the current models are known to be produced solely with plastics. [12]

Ebonite is used as an anticorrosive lining for various (mainly storage) vessels that contain diluted hydrochloric acid. It forms bubbles when storing hydrofluoric acid at temperatures above room temperature, or for prolonged durations. [13]

See also

Related Research Articles

<span class="mw-page-title-main">Polymer</span> Substance composed of macromolecules with repeating structural units

A polymer is a substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeating subunits derived from one or more species of monomers. Due to their broad spectrum of properties, both synthetic and natural polymers play essential and ubiquitous roles in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. Their consequently large molecular mass, relative to small molecule compounds, produces unique physical properties including toughness, high elasticity, viscoelasticity, and a tendency to form amorphous and semicrystalline structures rather than crystals.

<span class="mw-page-title-main">Natural rubber</span> Polymer harvested from certain trees

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, Indonesia, and Cambodia are four of the leading rubber producers.

<span class="mw-page-title-main">Vulcanization</span> Process of hardening rubber

Vulcanization is a range of processes for hardening rubbers. The term originally referred exclusively to the treatment of natural rubber with sulfur, which remains the most common practice. It has also grown to include the hardening of other (synthetic) rubbers via various means. Examples include silicone rubber via room temperature vulcanizing and chloroprene rubber (neoprene) using metal oxides.

<span class="mw-page-title-main">Chemical industry</span> Industry (branch), which is engaged in the manufacturing of chemical products

The chemical industry comprises the companies and other organizations that develop and produce industrial, specialty and other chemicals. Central to the modern world economy, it converts raw materials into commodity chemicals for industrial and consumer products. It includes industries for petrochemicals such as polymers for plastics and synthetic fibers; inorganic chemicals such as acids and alkalis; agricultural chemicals such as fertilizers, pesticides and herbicides; and other categories such as industrial gases, speciality chemicals and pharmaceuticals.

<span class="mw-page-title-main">Thermoplastic</span> Plastic that softens with heat and hardens on cooling

A thermoplastic, or thermosoftening plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling.

Polymer chemistry is a sub-discipline of chemistry that focuses on the structures of chemicals, chemical synthesis, and chemical and physical properties of polymers and macromolecules. The principles and methods used within polymer chemistry are also applicable through a wide range of other chemistry sub-disciplines like organic chemistry, analytical chemistry, and physical chemistry. Many materials have polymeric structures, from fully inorganic metals and ceramics to DNA and other biological molecules. However, polymer chemistry is typically related to synthetic and organic compositions. Synthetic polymers are ubiquitous in commercial materials and products in everyday use, such as plastics, and rubbers, and are major components of composite materials. Polymer chemistry can also be included in the broader fields of polymer science or even nanotechnology, both of which can be described as encompassing polymer physics and polymer engineering.

<span class="mw-page-title-main">Calender</span> Manufacturing device

A calender is a series of hard pressure rollers used to finish or smooth a sheet of material such as paper, textiles, rubber, or plastics. Calender rolls are also used to form some types of plastic films and to apply coatings. Some calender rolls are heated or cooled as needed. Calenders are sometimes misspelled calendars.

<span class="mw-page-title-main">EPDM rubber</span> Type of synthetic rubber

EPDM rubber is a type of synthetic rubber that is used in many applications.

Spin casting, also known as centrifugal rubber mold casting (CRMC), is a method of utilizing inertia to produce castings from a rubber mold. Typically, a disc-shaped mold is spun along its central axis at a set speed. The casting material, usually molten metal or liquid thermoset plastic, is then poured in through an opening at the top-center of the mold. The filled mold then continues to spin as the metal solidifies.

<span class="mw-page-title-main">Acrylate polymer</span> Group of polymers prepared from acrylate monomers

An acrylate polymer is any of a group of polymers prepared from acrylate monomers. These plastics are noted for their transparency, resistance to breakage, and elasticity.

Rubber Technology is the subject dealing with the transformation of rubbers or elastomers into useful products, such as automobile tires, rubber mats and, exercise rubber stretching bands. The materials includes latex, natural rubber, synthetic rubber and other polymeric materials, such as thermoplastic elastomers. Rubber processed through such methods are components of a wide range of items.

Membrane roofing is a type of roofing system for buildings, RV's, Ponds and in some cases tanks. It is used to create a watertight covering to protect the interior of a building. Membrane roofs are most commonly made from synthetic rubber, thermoplastic, or modified bitumen. Membrane roofs are most commonly used in commercial application, though they are becoming increasingly common in residential application.

Polymer engineering is generally an engineering field that designs, analyses, and modifies polymer materials. Polymer engineering covers aspects of the petrochemical industry, polymerization, structure and characterization of polymers, properties of polymers, compounding and processing of polymers and description of major polymers, structure property relations and applications.

Thermoplastic Vulcanizates (TPVs) are a type of thermoplastic elastomers (TPE) which undergo a vulcanization process during their manufacturing, imparting elastomeric properties to the final product. Vulcanization involves the cross-linking of polymer chains, leading to increased strength, durability, and flexibility. Unlike traditional vulcanized rubbers, TPVs can be melted and reprocessed multiple times, thanks to their thermoplastic nature. They are part of the thermoplastic elastomer family of polymers but are closest in elastomeric properties to ethylene propylene diene monomer (EPDM) rubber, combining the mechanical characteristics of vulcanized rubber with the processing properties of thermoplastics. Nearly 100 TPV grades are used globally across the automotive, household appliance, electrical, construction, and healthcare sectors.

<span class="mw-page-title-main">Forensic polymer engineering</span> Study of failure in polymeric products

Forensic polymer engineering is the study of failure in polymeric products. The topic includes the fracture of plastic products, or any other reason why such a product fails in service, or fails to meet its specification. The subject focuses on the material evidence from crime or accident scenes, seeking defects in those materials that might explain why an accident occurred, or the source of a specific material to identify a criminal. Many analytical methods used for polymer identification may be used in investigations, the exact set being determined by the nature of the polymer in question, be it thermoset, thermoplastic, elastomeric or composite in nature.

Sulfur concrete, sometimes named thioconcrete or sulfurcrete, is a composite construction material, composed mainly of sulfur and aggregate. Cement and water, important compounds in normal concrete, are not part of sulfur concrete. The concrete is heated above the melting point of elemental sulfur at ca. 140 °C (284 °F) in a ratio of between 12% and 25% sulfur, the rest being aggregate.

<span class="mw-page-title-main">Charles Goodyear Medal</span> Award

The Charles Goodyear Medal is the highest honor conferred by the American Chemical Society, Rubber Division. Established in 1941, the award is named after Charles Goodyear, the discoverer of vulcanization, and consists of a gold medal, a framed certificate and prize money. The medal honors individuals for "outstanding invention, innovation, or development which has resulted in a significant change or contribution to the nature of the rubber industry". Awardees give a lecture at an ACS Rubber Division meeting, and publish a review of their work in the society's scientific journal Rubber Chemistry and Technology.

Aubert Y. Coran (1932–2020) was an American scientist noted for his contributions to thermoplastic elastomers and vulcanization chemistry of rubber. In 1983, he won the Melvin Mooney Distinguished Technology Award, bestowed by the American Chemical Society to individuals "who have exhibited exceptional technical competency by making significant and repeated contributions to rubber science and technology". In 1995, the rubber division of the American Chemical Society bestowed on Coran the Charles Goodyear Medal in honor of his international contributions to polymer science and development.

In polymer chemistry, materials science, and food science, bloom refers to the migration of one component of a solid mixture to the surface of an article. The process is an example of phase separation or phase aggregation.

<span class="mw-page-title-main">Sulfur vulcanization</span> Process to transform the material properties of natural rubber

Sulfur vulcanization is a chemical process for converting natural rubber or related polymers into materials of varying hardness, elasticity, and mechanical durability by heating them with sulfur or sulfur-containing compounds. Sulfur forms cross-linking bridges between sections of polymer chains which affects the mechanical and electronic properties. Many products are made with vulcanized rubber, including tires, shoe soles, hoses, and conveyor belts. The term vulcanization is derived from Vulcan, the Roman god of fire.

References

  1. ↑ "Hartgummi (Ebonite)" (in German). Archived from the original on 2014-12-18. Retrieved 2014-11-30.
  2. ↑ "eboDUST Ebonite/Hard-rubber dust". Archived from the original on 2014-12-05. Retrieved 2014-11-30.
  3. ↑ Merriam-Webster (2002) [1961], "vulcanite", Webster's Third New International Dictionary, Unabridged , Springfield, Massachusetts, USA: Merriam-Webster.
  4. ↑ Seymour, Raymond Benedict; Deaning, Rudolph D. (1987). History of Polymeric Composites. VSP. p. 374.
  5. ↑ "ICE Virtual Library". Minutes of the Proceedings of the Institution of Civil Engineers. 189 (1912). Institute of Civil Engineers: 353. January 1912. doi:10.1680/imotp.1912.16587 . Retrieved 12 February 2019.
  6. ↑ "Care of Objects Made from Rubber and Plastic - CCI Notes 15/1". CCI Notes Series 15 (Modern Materials and Industrial Collections). Canadian Conservation Institute. Archived from the original on September 10, 2015. Retrieved August 28, 2015.
  7. ↑ Cooper, Dennis L. (2018-10-03), Bhowmick, Anil K.; Hall, Malcolm M.; Benarey, Henry A. (eds.), "Hard Rubber Compounds", Rubber Products Manufacturing Technology (1 ed.), Routledge, pp. 795–800, doi:10.1201/9780203740378-26, ISBN   978-0-203-74037-8, S2CID   198385857 , retrieved 2021-05-30
  8. ↑ "Bowling Balls: An In-Depth Overview". Bowling This Month. Retrieved August 29, 2015.
  9. ↑ "What Is Ebonite?". Unsharpen. Retrieved 19 July 2021.
  10. ↑ "Ebonite". fountainpen.it. Retrieved 2022-04-02.
  11. ↑ "Woodwinds & Brass Articles : The Music Room". www.wwbw.com.
  12. ↑ An easy way to identify a hard rubber comb is to rub part of its surface vigorously, then immediately smell the comb. Hard rubber's scent, resulting from the sulfur in the Ebonite, can usually be detected temporarily. The same effect can often be produced by running the comb under hot tap water.
  13. ↑ "Chemical Resistance Chart for Ebonite and various other Materials" (PDF).
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.