Pitch (resin)

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Pitch is a name for any of a number of viscoelastic polymers. Pitch can be natural or manufactured, derived from petroleum, coal tar, [1] or plants. Various forms of pitch may also be called tar, bitumen, or asphalt. Pitch produced from plants is also known as resin. Some products made from plant resin are also known as rosin.

Polymer substance composed of macromolecules with repeating structural units

A polymer is a large molecule, or macromolecule, composed of many repeated subunits. Due to their broad range 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, viscoelasticity, and a tendency to form glasses and semicrystalline structures rather than crystals. The terms polymer and resin are often synonymous with plastic.

Petroleum naturally occurring flammable liquid

Petroleum is a naturally occurring, yellowish-black liquid found in geological formations beneath the Earth's surface. It is commonly refined into various types of fuels. Components of petroleum are separated using a technique called fractional distillation, i.e. separation of a liquid mixture into fractions differing in boiling point by means of distillation, typically using a fractionating column.

Coal tar is a thick dark liquid which is a by-product of the production of coke and coal gas from coal. It has both medical and industrial uses. It may be applied to the affected area to treat psoriasis and seborrheic dermatitis (dandruff). It may be used in combination with ultraviolet light therapy. Industrially it is a railway tie preservative and used in the surfacing of roads.

Contents

Uses

Bucket of pitch Beckholmen Bucket of pitch.JPG
Bucket of pitch

Pitch was traditionally used to help caulk the seams of wooden sailing vessels (see shipbuilding). Pitch may also be used to waterproof wooden containers and in the making of torches. Petroleum-derived pitch is black in colour, hence the adjectival phrase, "pitch-black". [2]

Caulk application of flexible sealing compounds

Caulk or caulking is a material used to seal joints or seams against leakage in various structures and piping.

Shipbuilding construction of ships and floating vessels

Shipbuilding is the construction of ships and other floating vessels. It normally takes place in a specialized facility known as a shipyard. Shipbuilders, also called shipwrights, follow a specialized occupation that traces its roots to before recorded history.

Torch portable light source

A torch is a stick with combustible material at one end, which is ignited and used as a light source. Torches have been used throughout history, and are still used in processions, symbolic and religious events, and in juggling entertainment. In some countries "torch" in modern usage is the term for a battery-operated portable light.

Chasers pitch is used in jewellery making.

Viscoelastic properties

The pitch shown in this pitch drop experiment has a viscosity approximately 230 billion times that of water. University of Queensland Pitch drop experiment-white bg.jpg
The pitch shown in this pitch drop experiment has a viscosity approximately 230 billion times that of water.

Naturally occurring asphalt/bitumen, a type of pitch, is a viscoelastic polymer. This means that even though it seems to be solid at room temperature and can be shattered with a hard impact, it is actually fluid and will flow over time, but extremely slowly. The pitch drop experiment taking place at University of Queensland is a long-term experiment which demonstrates the flow of a piece of pitch over many years. For the experiment, pitch was put in a glass funnel and allowed to slowly drip out. Since the pitch was allowed to start dripping in 1930, only nine drops have fallen. It was calculated in the 1980s that the pitch in the experiment has a viscosity approximately 230 billion (2.3×1011) times that of water. [3] The eighth drop fell on 28 November 2000, and the ninth drop fell on 17 April 2014. [4] Another experiment was begun by a colleague of Nobel Prize winner Ernest Walton in the physics department of Trinity College in Ireland in 1944. Over the years, the pitch had produced several drops, but none had been recorded. On Thursday, July 11, 2013 scientists at Trinity College caught pitch dripping from a funnel on camera for the first time. [5]

Asphalt sticky, black and highly viscous liquid or semi-solid form of petroleum; bitumen variety

Asphalt, also known as bitumen, is a sticky, black, and highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term asphaltum was also used. The word is derived from the Ancient Greek ἄσφαλτος ásphaltos.

Pitch drop experiment long-term experiment which measures the flow of a piece of pitch

The pitch drop experiment is a long-term experiment which measures the flow of a piece of pitch over many years. 'Pitch' is the name for any of a number of highly viscous liquids which appear solid; most commonly bitumen. At room temperature, tar pitch flows at a very low rate, taking several years to form a single drop.

University of Queensland university in Australia

The University of Queensland (UQ) is a public research university primarily located in Queensland's capital city, Brisbane, Australia. Founded in 1909 by the state parliament, UQ is Australia's fifth oldest university. It is one of those colloquially known as a sandstone university. UQ is considered to be one of Australia's leading universities, and is ranked as the 48th most reputable university in the world. The University of Queensland is a founding member of online higher education consortium edX, Australia's research-intensive Group of Eight, and the global Universitas 21 network.

Winchester College has a 'pitch glacier' demonstration which has been running since 21st July 1906, but does not have records of regular measurements. [6]

Winchester College school in Winchester, Hampshire, England

Winchester College is an independent boarding school for boys in the British public school tradition, situated in Winchester, Hampshire. It has existed in its present location for over 600 years. It is the oldest of the original seven English public schools defined by the Clarendon Commission and regulated by the Public Schools Act 1868.

The viscoelastic properties of pitch make it well suited for the polishing of high-quality optical lenses and mirrors. In use, the pitch is formed into a lap or polishing surface, which is charged with iron oxide or cerium oxide. The surface to be polished is pressed into the pitch, then rubbed against the surface so formed. The ability of pitch to flow, albeit slowly, keeps it in constant uniform contact with the optical surface.

Production

The heating (dry distilling) of wood causes tar and pitch to drip away from the wood and leave behind charcoal. Birchbark is used to make birch-tar, a particularly fine tar. The terms tar and pitch are often used interchangeably. However, pitch is considered more solid, while tar is more liquid. Traditionally, pitch that was used for waterproofing buckets, barrels and small boats was drawn from pine. It is used to make Cutler's resin.

Dry distillation heating of solid materials to produce gaseous products (which may condense into liquids or solids)

Dry distillation is the heating of solid materials to produce gaseous products. The method may involve pyrolysis or thermolysis, or it may not. If there are no chemical changes, just phase changes, it resembles classical distillation, although it will generally need higher temperatures. Dry distillation in which chemical changes occur is a type of destructive distillation or cracking.

Tar substance

Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. Production and trade in pine-derived tar was a major contributor in the economies of Northern Europe and Colonial America. Its main use was in preserving wooden sailing vessels against rot. The largest user was the Royal Navy of the United Kingdom. Demand for tar declined with the advent of iron and steel ships.

Charcoal Lightweight black residue, made of carbon and ashes, after pyrolysis of animal or vegetal substances

Charcoal is a lightweight black carbon residue produced by removing water and other volatile constituents from animal and plant materials. Charcoal is usually produced by slow pyrolysis — the heating of wood or other organic materials in the absence of oxygen. This process is called charcoal burning. The finished charcoal consists largely of carbon.

See also

Related Research Articles

Drop (liquid) small unit of liquid

A drop or droplet is a small column of liquid, bounded completely or almost completely by free surfaces. A drop may form when liquid accumulates at the lower end of a tube or other surface boundary, producing a hanging drop called a pendant drop. Drops may also be formed by the condensation of a vapor or by atomization of a larger mass of liquid.

A non-Newtonian fluid is a fluid that does not follow Newton's law of viscosity, i.e. constant viscosity independent of stress. In non-Newtonian fluids, viscosity can change when under force to either more liquid or more solid. Ketchup, for example, becomes runnier when shaken and is thus a non-Newtonian fluid. Many salt solutions and molten polymers are non-Newtonian fluids, as are many commonly found substances such as custard, honey, toothpaste, starch suspensions, corn starch, paint, blood, and shampoo.

Tarmacadam is a road surfacing material made by combining macadam surfaces, tar, and sand, patented by Welsh inventor Edgar Purnell Hooley in 1902. The terms "tarmacadam" and tarmac are also used for a variety of other materials, including tar-grouted macadam, bituminous surface treatments, and modern asphalt concrete. The term is also often used to describe airport aprons, taxiways, and runways regardless of the surface.

Polydimethylsiloxane chemical compound, a linear polymer of dimethylsiloxane

Polydimethylsiloxane (PDMS), also known as dimethylpolysiloxane or dimethicone, belongs to a group of polymeric organosilicon compounds that are commonly referred to as silicones. PDMS is the most widely used silicon-based organic polymer, and is particularly known for its unusual rheological properties. PDMS is optically clear, and, in general, inert, non-toxic, and non-flammable. It is one of several types of silicone oil. Its applications range from contact lenses and medical devices to elastomers; it is also present in shampoos, food, caulking, lubricants and heat-resistant tiles.

Flat roof rooftype

A flat roof is a roof which is almost level in contrast to the many types of sloped roofs. The slope of a roof is properly known as its pitch and flat roofs have up to approximately 10°. Flat roofs are an ancient form mostly used in arid climates and allow the roof space to be used as a living space or a living roof. Flat roofs, or "low-slope" roofs, are also commonly found on commercial buildings throughout the world. The National Roofing Contractors Association defines a low-slope roof as having a slope of 3-in-12 or less.

Heavy crude oil is highly-viscous oil that cannot easily flow to production wells under normal reservoir conditions.

Petroleum seep

A petroleum seep is a place where natural liquid or gaseous hydrocarbons escape to the earth's atmosphere and surface, normally under low pressure or flow. Seeps generally occur above either terrestrial or offshore petroleum accumulation structures. The hydrocarbons may escape along geological layers, or across them through fractures and fissures in the rock, or directly from an outcrop of oil-bearing rock.

Kraton is the trade name given to a number of high performance elastomers manufactured by Kraton Polymers, and used as synthetic replacements for rubber. Kraton polymers offers many of the properties of natural rubber, such as flexibility, high traction, and sealing abilities, but with increased resistance to heat, weathering, and chemicals. It was first made by the chemical division of the Shell Oil Company in the 1950s, under the technical leadership of Murray Luftglass and Norman R. Legge. Shell sold its Kraton polymers business to private equity firm Ripplewood Holdings in March 2001.

Pyrolysis oil, sometimes also known as biocrude or bio-oil, is a synthetic fuel under investigation as substitute for petroleum. It is obtained by heating dried biomass without oxygen in a reactor at a temperature of about 500 °C with subsequent cooling. Pyrolytic oil is a kind of tar and normally contains levels of oxygen too high to be considered a hydrocarbon. This high oxygen content results in non-volatility, corrosiveness, immiscibity with fossil fuels, thermal instability, and a tendency to polymerize when exposed to air. As such, it is distinctly different from petroleum products. Removing oxygen from bio-oil or nitrogen from algal bio-oil is called upgrading.

Sealant substance used to block the passage of fluids through the surface or joints or openings in materials

Sealant is a substance used to block the passage of fluids through the surface or joints or openings in materials, a type of mechanical seal. In building construction sealant is sometimes synonymous with caulking and also serve the purposes of blocking dust, sound and heat transmission. Sealants may be weak or strong, flexible or rigid, permanent or temporary. Sealants are not adhesives but some have adhesive qualities and are called adhesive-sealants or structural sealants.

Bituminous waterproofing

Bituminous waterproofing systems are designed to protect residential and commercial buildings. Bitumen is a mixed substance made up of organic liquids that are highly sticky, viscous, and waterproof. These systems are sometimes used to construct roofs, in the form of roofing felt or roll roofing products.

The Asphalt industry in Trinidad is located at the Pitch Lake at the town of La Brea in southwestern Trinidad, Trinidad and Tobago and it has gained a reputation for itself as the world's largest deposit. The Pitch Lake is considered a tourist attraction and attracts about 20,000 visitors annually. It is also mined for asphalt by Lake Asphalt of Trinidad and Tobago.

Asphalt roll roofing

Asphalt roll roofing or membrane is a roofing material commonly used for buildings that feature a low sloped roof pitch in North America. The material is based on the same materials used in asphalt shingles; an organic felt or fiberglass mat, saturated with asphalt, and faced with granular stone aggregate.

McKittrick Tar Pits

The McKittrick Tar Pits are a series of natural asphalt lakes situated in the western part of Kern County in southern California. The pits are the most extensive asphalt lakes in the state.

Carpinteria Tar Pits

The Carpinteria Tar Pits are a series of natural asphalt lakes situated in the southern part of Santa Barbara County in southern California.

Pyrobitumen bitumen variety

Pyrobitumen is a type of solid, amorphous organic matter. Pyrobitumen is mostly insoluble in carbon disulfide and other organic solvents as a result of molecular cross-linking, which renders previously soluble organic matter insoluble. Not all solid bitumens are pyrobitumens, in that some solid bitumens are soluble in common organic solvents, including CS
2
, dichloromethane, and benzene-methanol mixtures.

References

  1. COAL-TAR PITCH, HIGH TEMPERATURE
  2. Oxford English Dictionary "pitch, n.1", phrases P1
  3. The Pitch Drop Experiment
  4. Biever, Celeste; Lisa Grossman (17 April 2014). "Longest experiment sees pitch drop after 84-year wait". New Scientist . Retrieved 23 June 2014.
  5. "Trinity College experiment succeeds after 69 years". RTÉ News. 24 July 2013. Retrieved 23 June 2014.
  6. Gregory, Martin. "Pitch Flow Demonstrations, 1906". In Foster, Richard (ed.). 50 Treasures from Winchester College. SCALA. p. 123. ISBN   9781785512209.