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82-406: Blow molding (or moulding ) is a manufacturing process for forming hollow plastic parts. It is also used for forming glass bottles or other hollow shapes. In general, there are three main types of blow molding: extrusion blow molding, injection blow molding, and injection stretch blow molding. The blow molding process begins with softening plastic by heating a preform or parison . The parison

164-416: A conductive connection between the active device and the metal contacts used to operate the circuit, while acting as a diffusion barrier to block the diffusion of the metal into the silicon. In this context, TiN is classified as a "barrier metal" (electrical resistivity ~ 25 μΩ·cm ), even though it is clearly a ceramic from the perspective of chemistry or mechanical behavior. Recent chip design in

246-424: A polymer blend , such as high impact polystyrene . Large companies may do their own compounding prior to production, but some producers have it done by a third party. Companies that specialize in this work are known as Compounders. The compounding of thermosetting plastic is relatively straightforward; as it remains liquid until it is cured into its final form. For thermosoftening materials, which are used to make

328-611: A brown color and appears gold when applied as a coating. Depending on the substrate material and surface finish, TiN has a coefficient of friction ranging from 0.4 to 0.9 against another TiN surface (non-lubricated). The typical TiN formation has a crystal structure of NaCl type with a roughly 1:1 stoichiometry ; TiN x compounds with x ranging from 0.6 to 1.2 are, however, thermodynamically stable. TiN becomes superconducting at cryogenic temperatures, with critical temperature up to 6.0 K for single crystals. Superconductivity in thin-film TiN has been studied extensively, with

410-534: A coating of less than 5 micrometres (0.00020 in) is applied. TiN has a Vickers hardness of 1800–2100, hardness of 31 ± 4 GPa , a modulus of elasticity of 550 ± 50 GPa , a thermal expansion coefficient of 9.35 × 10  K , and a superconducting transition temperature of 5.6 K. TiN oxidizes at 800 °C in a normal atmosphere. It is chemically stable at 20 °C, according to laboratory tests, but can be slowly attacked by concentrated acid solutions with rising temperatures. TiN has

492-413: A coating, it is used in aerospace and military applications and to protect the sliding surfaces of suspension forks of bicycles and motorcycles , as well as the shock shafts of radio-controlled cars . TiN is also used as a protective coating on the moving parts of many rifles and semi-automatic firearms, as it is extremely durable. As well as being durable, it is also extremely smooth, making removing

574-512: A conductivity of up to 80 kS/cm in stretch-oriented polyacetylene , has been achieved, it does not approach that of most metals. For example, copper has a conductivity of several hundred kS/cm. Biodegradable plastics are plastics that degrade (break down) upon exposure to sunlight or ultra-violet radiation ; water or dampness; bacteria; enzymes; or wind abrasion. Attack by insects, such as waxworms and mealworms, can also be considered as forms of biodegradation. Aerobic degradation requires that

656-569: A cooling period the blow mold opens and the core rod is rotated to the ejection position. The finished article is stripped off the core rod and as an option can be leak-tested prior to packing. The preform and blow mold can have many cavities, typically three to sixteen depending on the article size and the required output. There are three sets of core rods, which allow concurrent preform injection, blow molding and ejection. Injection Stretch Blow Molding has two main different methods, namely Single-stage and Double-stage process. The Single-stage process

738-479: A dark, iridescent , bluish-purple, depending on the exact process of application. These coatings are becoming common on sporting goods, particularly knives and handguns , where they are used for both aesthetic and functional reasons. Titanium nitride is also produced intentionally, within some steels, by judicious addition of titanium to the alloy . TiN forms at very high temperatures because of its very low enthalpy of formation , and even nucleates directly from

820-501: A factor of 30 times. The process of injection blow molding ( IBM ) is used for the production of hollow glass and plastic objects in large quantities. In the IBM process, the polymer is injection molded onto a core pin; then the core pin is rotated to a blow molding station to be inflated and cooled. This is the least-used of the three blow molding processes, and is typically used to make small medical and single serve bottles. The process

902-630: A finished plastic may be non-toxic, the monomers used in the manufacture of its parent polymers may be toxic. In some cases, small amounts of those chemicals can remain trapped in the product unless suitable processing is employed. For example, the World Health Organization 's International Agency for Research on Cancer (IARC) has recognized vinyl chloride , the precursor to PVC, as a human carcinogen. Some plastic products degrade to chemicals with estrogenic activity. The primary building block of polycarbonates, bisphenol A (BPA),

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984-408: A heated tube. Once the plastic is melted the screw stops rotating and linearly moves to push the melt out. With the accumulator method, an accumulator gathers melted plastic and after the previous mold has cooled and enough plastic has accumulated, a rod pushes the melted plastic and forms the parison. In this case the screw may turn continuously or intermittently. With continuous extrusion the weight of

1066-530: A hollow tube forming a tube like piece of plastic with a hole in one end for compressed gas - known as a parison. The parison is captured by closing it into a cooled metal mold. Air is blown into the parison, inflating it into the shape of the hollow bottle , container, or part. After the plastic has cooled, the mold is opened and the part is ejected. "Straight extrusion blow molding is a way of propelling material forward similar to injection molding whereby an Archimedean screw turns, feeding plastic material down

1148-408: A large molecular weight, they are biochemically inert. Plastic products contain a variety of additives, however, some of which can be toxic. For example, plasticizers like adipates and phthalates are often added to brittle plastics like PVC to make them pliable enough for use in food packaging, toys, and many other items. Traces of these compounds can leach out of the product. Owing to concerns over

1230-417: A material with inconsistent properties, which can be unappealing to industry. For example, mixing different colored plastics with different plastic colorants together can produce a discolored or brown material and for this reason plastic is usually sorted by both polymer type and color before recycling. Absence of transparency and reporting across the value chain often results in lack of knowledge concerning

1312-500: A mixture of private and state-owned enterprises. Roughly half of all production takes place in East Asia, with China being the largest single producer. Major international producers include: Historically, Europe and North America have dominated global plastics production. However, since 2010 Asia has emerged as a significant producer, with China accounting for 31% of total plastic resin production in 2020. Regional differences in

1394-486: A new disease caused solely by plastics, was discovered in seabirds. The birds identified as having the disease have scarred digestive tracts from ingesting plastic waste. "When birds ingest small pieces of plastic, they found, it inflames the digestive tract. Over time, the persistent inflammation causes tissues to become scarred and disfigured, affecting digestion, growth and survival." Pure plastics have low toxicity due to their insolubility in water, and because they have

1476-692: A particular purpose. Examples include thermoplastics , thermosets , conductive polymers , biodegradable plastics , engineering plastics and elastomers . One important classification of plastics is the degree to which the chemical processes used to make them are reversible or not. Thermoplastics do not undergo chemical change in their composition when heated and thus can be molded repeatedly. Examples include polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC). Thermosets, or thermosetting polymers, can melt and take shape only once: after they have solidified, they stay solid. If reheated, thermosets decompose rather than melt. In

1558-674: A pattern of more regularly spaced atoms, such as high-density polyethylene (HDPE), polybutylene terephthalate (PBT), and polyether ether ketone (PEEK). However, some plastics are partially amorphous and partially crystalline in molecular structure, giving them both a melting point and one or more glass transitions (the temperature above which the extent of localized molecular flexibility is substantially increased). These so-called semi-crystalline plastics include polyethylene, polypropylene, polyvinyl chloride, polyamides (nylons), polyesters and some polyurethanes. Intrinsically Conducting Polymers (ICP) are organic polymers that conduct electricity. While

1640-519: A turnover of more than 360 billion euros per year. In China in 2016 there were over 15,000 plastic manufacturing companies, generating more than US$ 366 billion in revenue. In 2017, the global plastics market was dominated by thermoplastics – polymers that can be melted and recast. Thermoplastics include polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS) and synthetic fibers, which together represent 86% of all plastics. Plastic

1722-594: A variety of shapes: films, fibers, plates, tubes, bottles and boxes, among many others. Plasticity also has a technical definition in materials science outside the scope of this article; it refers to the non-reversible change in form of solid substances. Most plastics contain organic polymers. The vast majority of these polymers are formed from chains of carbon atoms, with or without the attachment of oxygen, nitrogen or sulfur atoms. These chains comprise many repeating units formed from monomers . Each polymer chain consists of several thousand repeating units. The backbone

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1804-671: A wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to their widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum ; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives. Between 1950 and 2017 9.2 billion metric tons of plastic are estimated to have been made; more than half of this has been produced since 2004. In 2020, 400 million tons of plastic were produced. If global trends on plastic demand continue, it

1886-547: Is sublimed and reacted with nitrogen in a high-energy, vacuum environment. TiN film may also be produced on Ti workpieces by reactive growth (for example, annealing ) in a nitrogen atmosphere. PVD is preferred for steel parts because the deposition temperatures exceeds the austenitizing temperature of steel. TiN layers are also sputtered on a variety of higher-melting-point materials such as stainless steels , titanium and titanium alloys . Its high Young's modulus (values between 450 and 590  GPa have been reported in

1968-403: Is a global treaty to protect human health and the environment from chemicals that remain intact in the environment for long periods, become widely distributed geographically, accumulate in the fatty tissue of humans and wildlife, and have harmful impacts on human health or on the environment. Other additives proven to be harmful such as cadmium , chromium , lead and mercury (regulated under

2050-405: Is a tube-like piece of plastic with a hole in one end through which compressed air can enter. The plastic workpiece is then clamped into a mold and air is blown into it. The air pressure inflates the plastic which conforms to the mold. Once the plastic has cooled and hardened the mold opens and the part is ejected. Water channels within the mold assist cooling. The process principle comes from

2132-721: Is also used as a coating on some compression driver diaphragms to improve performance. Owing to their high biostability, TiN layers may also be used as electrodes in bioelectronic applications like in intelligent implants or in-vivo biosensors that have to withstand the severe corrosion caused by body fluids . TiN electrodes have already been applied in the subretinal prosthesis project as well as in biomedical microelectromechanical systems ( BioMEMS ). The most common methods of TiN thin film creation are physical vapor deposition (PVD, usually sputter deposition , cathodic arc deposition or electron-beam heating ) and chemical vapor deposition (CVD). In both methods, pure titanium

2214-531: Is an estrogen-like endocrine disruptor that may leach into food. Research in Environmental Health Perspectives finds that BPA leached from the lining of tin cans, dental sealants and polycarbonate bottles can increase the body weight of lab animals' offspring. A more recent animal study suggests that even low-level exposure to BPA results in insulin resistance, which can lead to inflammation and heart disease. As of January 2010,

2296-555: Is as packaging materials, but they are used in a wide range of other sectors, including: construction (pipes, gutters, door and windows), textiles ( stretchable fabrics , fleece ), consumer goods (toys, tableware, toothbrushes), transportation (headlights, bumpers, body panels , wing mirrors ), electronics (phones, computers, televisions) and as machine parts. In optics, plastics are used to manufacture aspheric lenses. Additives are chemicals blended into plastics to change their performance or appearance, making it possible to alter

2378-488: Is burned, especially when burning is uncontrolled or takes place in low- technology incinerators, as is common in many developing countries. Incomplete combustion can cause emissions of hazardous substances such as acid gases and ash which can contain persistent organic pollutants (POPs) such as dioxins . A number of additives identified as hazardous to humans and/or the environment are regulated internationally. The Stockholm Convention on Persistent Organic Pollutants (POPs)

2460-408: Is divided into three steps: injection, blowing and ejection. The injection blow molding machine is based on an extruder barrel and screw assembly which melts the polymer . The molten polymer is fed into a hot runner manifold where it is injected through nozzles into a heated cavity and core pin. The cavity mold forms the external shape and is clamped around a core rod which forms the internal shape of

2542-496: Is estimated that annual global plastic production will reach over 1.1 billion tons by 2050. The success and dominance of plastics starting in the early 20th century has caused widespread environmental problems, due to their slow decomposition rate in natural ecosystems. Most plastic produced has not been reused, or is incapable of reuse, either being captured in landfills or persisting in the environment as plastic pollution and microplastics . Plastic pollution can be found in all

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2624-466: Is for edge retention and corrosion resistance on machine tooling, such as drill bits and milling cutters , often improving their lifetime by a factor of three or more. Because of the metallic gold color of TiN, this material is used to coat costume jewelry and automotive trim for decorative purposes. TiN is also widely used as a top-layer coating, usually with nickel - or chromium -plated substrates, on consumer plumbing fixtures and door hardware. As

2706-446: Is not sold as a pure unadulterated substance, but is instead mixed with various chemicals and other materials, which are collectively known as additives. These are added during the compounding stage and include substances such as stabilizers , plasticizers and dyes , which are intended to improve the lifespan, workability or appearance of the final item. In some cases, this can involve mixing different types of plastic together to form

2788-414: Is performed by simply remelting and reforming used plastic into new items. Additives present risks in recycled products, as they are difficult to remove. When plastic products are recycled, it is highly likely that the additives will be integrated into the new products. Waste plastic, even if it is all of the same polymer type, will contain varying types and amounts of additives. Mixing these together can give

2870-448: Is the part of the chain that is on the main path , linking together a large number of repeat units. To customize the properties of a plastic, different molecular groups called side chains hang from this backbone; they are usually hung from the monomers before the monomers themselves are linked together to form the polymer chain. The structure of these side chains influences the properties of the polymer. Plastics are usually classified by

2952-460: Is then again broken down into 3-station and 4-station machines. In the single-stage process, both preform manufacture and bottle blowing is performed in the same machine. The older 4-station method of injection, reheat, stretch blow and ejection is more costly than the 3-station machine which eliminates the reheat stage and uses latent heat in the preform, thus saving costs of energy to reheat and 25% reduction in tooling. The process explained: Imagine

3034-646: The Los Angeles Times reported that the US Food and Drug Administration (FDA) is spending $ 30 million to investigate indications of BPA's link to cancer. Bis(2-ethylhexyl) adipate , present in plastic wrap based on PVC, is also of concern, as are the volatile organic compounds present in new car smell . The EU has a permanent ban on the use of phthalates in toys. In 2009, the US government banned certain types of phthalates commonly used in plastic. Because

3116-473: The Minamata Convention on Mercury ), which have previously been used in plastic production, are banned in many jurisdictions. However they are still routinely found in some plastic packaging including food packaging. The use of the additive bisphenol A (BPA) in plastic baby bottles is banned in many parts of the world, but is not restricted in some low-income countries. In 2023, plasticosis ,

3198-462: The polymerization of their starting materials ( monomers ); which are almost always petrochemical in nature. Such facilities are normally large and are visually similar to oil refineries , with sprawling pipework running throughout. The large size of these plants allows them to exploit economies of scale . Despite this, plastic production is not particularly monopolized, with about 100 companies accounting for 90% of global production. This includes

3280-402: The 1950s. Others estimate a cumulative human production of 8.3 billion tons of plastic, of which 6.3 billion tons is waste, with only 9% getting recycled. Titanium nitride Applied as a thin coating, TiN is used to harden and protect cutting and sliding surfaces, for decorative purposes (for its golden appearance), and as a non-toxic exterior for medical implants . In most applications

3362-493: The 45 nm technology and beyond also makes use of TiN as a "metal" for improved transistor performance. In combination with gate dielectrics (e.g. HfSiO 4 ) that have a higher permittivity compared to standard SiO 2 , the gate length can be scaled down with low leakage , higher drive current and the same or better threshold voltage . Additionally, TiN thin films are currently under consideration for coating zirconium alloys for accident-tolerant nuclear fuels. It

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3444-494: The EU, over 400 additives are used in high volumes. In a global market analysis, 5,500 additives were found. At a minimum, all plastic contains some polymer stabilizers which permit them to be melt-processed (molded) without suffering polymer degradation . Other additives are optional and can be added as required, with loadings varying significantly between applications. The amount of additives contained in plastics varies depending on

3526-485: The Greek πλαστικός ( plastikos ), meaning "capable of being shaped or molded ;" in turn, it is from πλαστός ( plastos ) meaning "molded." As a noun , the word most commonly refers to the solid products of petrochemical-derived manufacturing. The noun plasticity refers specifically here to the deformability of the materials used in the manufacture of plastics. Plasticity allows molding , extrusion or compression into

3608-598: The ISBM process, the preforms are heated (typically using infrared heaters) above their glass transition temperature, then blown using high-pressure air into bottles using metal blow molds. The preform is always stretched with a core rod as part of the process. Plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be molded , extruded or pressed into solid objects of various shapes. This adaptability, plus

3690-561: The North American Free Trade Agreement or NAFTA region) accounts for 21% of global plastic consumption, closely followed by China (20%) and Western Europe (18%). In North America and Europe, there is high per capita plastic consumption (94 kg and 85 kg/capita/year, respectively). In China, there is lower per capita consumption (58 kg/capita/year), but high consumption nationally because of its large population. The largest application for plastics

3772-516: The United States Environmental Protection Agency (US EPA) revealed that out of 3,377 chemicals potentially associated with plastic packaging and 906 likely associated with it, 68 were ranked by ECHA as "highest for human health hazards" and 68 as "highest for environmental hazards". As additives change the properties of plastics they have to be considered during recycling. Presently, almost all recycling

3854-486: The additives' function. For example, additives in polyvinyl chloride (PVC) can constitute up to 80% of the total volume. Pure unadulterated plastic (barefoot resin) is never sold, even by the primary producers. Additives may be weakly bound to the polymers or react in the polymer matrix. Although additives are blended into plastic they remain chemically distinct from it, and can gradually leach back out during normal use, when in landfills, or following improper disposal in

3936-534: The birth of the plastic industry in the 1950s, global production has increased enormously, reaching 400 million tonnes a year in 2021; this is up from 381 million metric tonnes in 2015 (excluding additives). From the 1950s, rapid growth occurred in the use of plastics for packaging, in building and construction, and in other sectors. If global trends on plastic demand continue, it is estimated that by 2050 annual global plastic production will exceed 1.1 billion tonnes annually. Plastics are produced in chemical plants by

4018-543: The blowing technique were established very early on. Because glass is very breakable, after the introduction of plastic, plastic was used to replace glass in some cases. The first mass production of plastic bottles was done in America in 1939. Germany started using this technology a little bit later but is currently one of the leading manufacturers of blow molding machines. In the United States soft drink industry ,

4100-453: The carbon build-up extremely easy. TiN is non-toxic, meets FDA guidelines, and has seen use in medical devices such as scalpel blades and orthopedic bone-saw blades, where sharpness and edge retention are important. TiN coatings have also been used in implanted prostheses (especially hip replacement implants) and other medical implants. Though less visible, thin films of TiN are also used in microelectronics , where they serve as

4182-690: The chemical profile of the final products. For example, products containing brominated flame retardants have been incorporated into new plastic products. Flame retardants are a group of chemicals used in electronic and electrical equipment, textiles, furniture and construction materials which should not be present in food packaging or child care products. A recent study found brominated dioxins as unintentional contaminants in toys made from recycled plastic electronic waste that contained brominated flame retardants. Brominated dioxins have been found to exhibit toxicity similar to that of chlorinated dioxins. They can have negative developmental effects and negative effects on

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4264-448: The chemical structure of most plastics renders them durable, they are resistant to many natural degradation processes. Much of this material may persist for centuries or longer, given the demonstrated persistence of structurally similar natural materials such as amber . There are differing estimates of how much plastic waste has been produced in the last century. By one estimate, one billion tons of plastic waste have been discarded since

4346-802: The chemical structure of the polymer's backbone and side chains. Important groups classified in this way include the acrylics , polyesters , silicones , polyurethanes , and halogenated plastics . Plastics can be classified by the chemical process used in their synthesis, such as condensation , polyaddition , and cross-linking . They can also be classified by their physical properties, including hardness , density , tensile strength , thermal resistance , and glass transition temperature . Plastics can additionally be classified by their resistance and reactions to various substances and processes, such as exposure to organic solvents, oxidation , and ionizing radiation . Other classifications of plastics are based on qualities relevant to manufacturing or product design for

4428-452: The commodity plastics, with many having exceptional properties. Engineering plastics are more robust and are used to make products such as vehicle parts, building and construction materials, and some machine parts. In some cases they are polymer blends formed by mixing different plastics together (ABS, HIPS etc.). Engineering plastics can replace metals in vehicles, lowering their weight and improving fuel efficiency by 6–8%. Roughly 50% of

4510-513: The developing world, the applications of plastic may differ; 42% of India's consumption is used in packaging. In the medical field, polymer implants and other medical devices are derived at least partially from plastic. Worldwide, about 50 kg of plastic is produced annually per person, with production doubling every ten years. The world's first fully synthetic plastic was Bakelite , invented in New York in 1907, by Leo Baekeland , who coined

4592-666: The effects of such leachates , the EU has restricted the use of DEHP (di-2-ethylhexyl phthalate) and other phthalates in some applications, and the US has limited the use of DEHP, DPB , BBP , DINP , DIDP , and DnOP in children's toys and child-care articles through the Consumer Product Safety Improvement Act . Some compounds leaching from polystyrene food containers have been proposed to interfere with hormone functions and are suspected human carcinogens (cancer-causing substances). Other chemicals of potential concern include alkylphenols . While

4674-401: The environment. Additives may also degrade to form other toxic molecules. Plastic fragmentation into microplastics and nanoplastics can allow chemical additives to move in the environment far from the point of use. Once released, some additives and derivatives may persist in the environment and bioaccumulate in organisms. They can have adverse effects on human health and biota. A recent review by

4756-407: The finite limits of fossil fuel reserves and to rising levels of greenhouse gases caused primarily by the burning of those fuels, the development of bioplastics is a growing field. Global production capacity for bio-based plastics is estimated at 327,000 tonnes per year. In contrast, global production of polyethylene (PE) and polypropylene (PP), the world's leading petrochemical-derived polyolefins,

4838-568: The host resin. Masterbatch granules can be mixed with cheaper bulk polymer and will release their additives during processing to give a homogeneous final product. This can be cheaper than working with a fully compounded material and is particularly common for the introduction of color. Companies that produce finished goods are known as converters (sometimes processors). The vast majority of plastics produced worldwide are thermosoftening and must be heated until molten in order to be molded. Various sorts of extrusion equipment exist which can then form

4920-506: The idea of glassblowing . Enoch Ferngren and William Kopitke produced a blow molding machine and sold it to Hartford Empire Company in 1938. This was the beginning of the commercial blow molding process. During the 1940s the variety and number of products were still very limited and therefore blow molding did not take off until later. Once the variety and production rates went up the number of products created soon followed. The technical mechanisms needed to produce hollow-bodied workpieces using

5002-402: The literature ) means that thick coatings tend to flake away, making them much less durable than thin ones. Titanium-nitride coatings can also be deposited by thermal spraying whereas TiN powders are produced by nitridation of titanium with nitrogen or ammonia at 1200 °C. Bulk ceramic objects can be fabricated by packing powdered metallic titanium into the desired shape, compressing it to

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5084-604: The majority of products, it is necessary to melt the plastic in order to mix-in the additives. This involves heating it to anywhere between 150–320 °C (300–610 °F). Molten plastic is viscous and exhibits laminar flow , leading to poor mixing. Compounding is therefore done using extrusion equipment, which is able to supply the necessary heat and mixing to give a properly dispersed product. The concentrations of most additives are usually quite low, however high levels can be added to create Masterbatch products. The additives in these are concentrated but still properly dispersed in

5166-619: The molding process. This is trimmed off by spinning a cutting blade around the container which separates the material. The excess plastic is then recycled to create new moldings. Spin Trimmers are used on a number of materials, such as PVC, HDPE and PE+LDPE. Different types of the materials have their own physical characteristics affecting trimming. For example, moldings produced from amorphous materials are much more difficult to trim than crystalline materials. Titanium nitride -coated blades are often used rather than standard steel to increase life by

5248-443: The molecules are small round balls, when together they have large air gaps and small surface contact, by first stretching the molecules vertically then blowing to stretch horizontally the biaxial stretching makes the molecules a cross shape. These "crosses" fit together leaving little space as more surface area is contacted thus making the material less porous and increasing barrier strength against permeation. This process also increases

5330-450: The nervous system and interfere with mechanisms of the endocrine system. Many of the controversies associated with plastics actually relate to their additives, as some compounds can be persistent, bioaccumulating and potentially harmful. The now banned flame retardants OctaBDE and PentaBDE are an example of this, while the health effects of phthalates are an ongoing area of public concern. Additives can also be problematic if waste

5412-420: The number of plastic containers went from zero in 1977 to ten billion pieces in 1999. Today, an even greater number of products are blown and it is expected to keep increasing. For amorphous metals , also known as bulk metallic glasses, blow molding has been recently demonstrated under pressures and temperatures comparable to plastic blow molding. In extrusion blow molding, plastic is melted and extruded into

5494-617: The parison drags the parison and makes calibrating the wall thickness difficult. The accumulator head or reciprocating screw methods use hydraulic systems to push the parison out quickly reducing the effect of the weight and allowing precise control over the wall thickness by adjusting the die gap with a parison programming device. Continuous extrusion equipment includes rotary wheel blow molding systems and shuttle machinery , while intermittent extrusion machinery includes reciprocating screw machinery and accumulator head machinery . Containers such as jars often have an excess of material due to

5576-709: The plastic be exposed at the surface, whereas anaerobic degradation would be effective in landfill or composting systems. Some companies produce biodegradable additives to enhance biodegradation. Although starch powder can be added as a filler to allow some plastics to degrade more easily, such treatment does not lead to complete breakdown. Some researchers have genetically engineered bacteria to synthesize completely biodegradable plastics, such as polyhydroxy butyrate (PHB); however, these were still relatively costly as of 2021. While most plastics are produced from petrochemicals, bioplastics are made substantially from renewable plant materials like cellulose and starch. Due both to

5658-571: The plastic into almost any shape. For thermosetting materials the process is slightly different, as the plastics are liquid to begin with and but must be cured to give solid products, but much of the equipment is broadly similar. The most commonly produced plastic consumer products include packaging made from LDPE (e.g. bags, containers, food packaging film), containers made from HDPE (e.g. milk bottles, shampoo bottles, ice cream tubs), and PET (e.g. bottles for water and other drinks). Together these products account for around 36% of plastics use in

5740-464: The preferred choice for the mass production everyday objects. Their biggest single application is in packaging, with some 146 million tonnes being used this way in 2015, equivalent to 36% of global production. Due to their dominance; many of the properties and problems commonly associated with plastics, such as pollution stemming from their poor biodegradability , are ultimately attributable to commodity plastics. A huge number of plastics exist beyond

5822-423: The preform. The preform consists of a fully formed bottle/jar neck with a thick tube of polymer attached, which will form the body. similar in appearance to a test tube with a threaded neck. The preform mold opens and the core rod is rotated and clamped into the hollow, chilled blow mold. The end of the core rod opens and allows compressed air into the preform, which inflates it to the finished article shape. After

5904-688: The proper density, then igniting it in an atmosphere of pure nitrogen. The heat released by the chemical reaction between the metal and gas is sufficient to sinter the nitride reaction product into a hard, finished item. See powder metallurgy . There are several commercially used variants of TiN that have been developed since 2010, such as titanium carbon nitride (TiCN), titanium aluminium nitride (TiAlN or AlTiN), and titanium aluminum carbon nitride, which may be used individually or in alternating layers with TiN. These coatings offer similar or superior enhancements in corrosion resistance and hardness, and additional colors ranging from light gray to nearly black, to

5986-413: The properties of plastics to better suit their intended applications. Additives are therefore one of the reasons why plastic is used so widely. Plastics are composed of chains of polymers. Many different chemicals are used as plastic additives. A randomly chosen plastic product generally contains around 20 additives. The identities and concentrations of additives are generally not listed on products. In

6068-411: The strength to be ideal for filling with carbonated drinks. In the two-stage injection stretch blow molding process, the plastic is first molded into a "preform" using the injection molding process. These preforms are produced with the necks of the bottles, including threads (the "finish") on one end. These preforms are packaged, and fed later (after cooling) into a reheat stretch blow molding machine. In

6150-483: The superconducting properties strongly varying depending on sample preparation, up to complete suppression of superconductivity at a superconductor–insulator transition . A thin film of TiN was chilled to near absolute zero , converting it into the first known superinsulator , with resistance suddenly increasing by a factor of 100,000. Osbornite is a very rare natural form of titanium nitride, found almost exclusively in meteorites. A well-known use for TiN coating

6232-528: The term "plastics". Dozens of different types of plastics are produced today, such as polyethylene , which is widely used in product packaging , and polyvinyl chloride (PVC), used in construction and pipes because of its strength and durability. Many chemists have contributed to the materials science of plastics, including Nobel laureate Hermann Staudinger , who has been called "the father of polymer chemistry ," and Herman Mark , known as "the father of polymer physics ". The word plastic derives from

6314-762: The thermosetting process, an irreversible chemical reaction occurs. The vulcanization of rubber is an example of this process. Before heating in the presence of sulfur, natural rubber ( polyisoprene ) is a sticky, slightly runny material; after vulcanization, the product is dry and rigid. Around 70% of global production is concentrated in six major polymer types, the so-called commodity plastics . Unlike most other plastics these can often be identified by their resin identification code (RIC): Polyurethanes (PUR) and PP&A fibers are often also included as major commodity classes, although they usually lack RICs, as they are chemically quite diverse groups. These materials are inexpensive, versatile and easy to work with, making them

6396-444: The volume of modern cars is made of plastic, but this only accounts for 12–17% of the vehicle weight. High-performance plastics are usually expensive, with their use limited to specialized applications which make use of their superior properties. Many plastics are completely amorphous (without a highly ordered molecular structure), including thermosets, polystyrene, and methyl methacrylate (PMMA). Crystalline plastics exhibit

6478-518: The volume of plastics production are driven by user demand, the price of fossil fuel feedstocks, and investments made in the petrochemical industry. For example, since 2010 over US$ 200 billion has been invested in the United States in new plastic and chemical plants, stimulated by the low cost of raw materials. In the European Union (EU), too, heavy investments have been made in the plastics industry, which employs over 1.6 million people with

6560-497: The world's major water bodies , for example, creating garbage patches in all of the world's oceans and contaminating terrestrial ecosystems. Of all the plastic discarded so far, some 14% has been incinerated and less than 10% has been recycled. In developed economies, about a third of plastic is used in packaging and roughly the same in buildings in applications such as piping , plumbing or vinyl siding . Other uses include automobiles (up to 20% plastic ), furniture, and toys. In

6642-726: The world. Most of them (e.g. disposable cups, plates, cutlery, takeaway containers, carrier bags) are used for only a short period, many for less than a day. The use of plastics in building and construction, textiles, transportation and electrical equipment also accounts for a substantial share of the plastics market. Plastic items used for such purposes generally have longer life spans. They may be in use for periods ranging from around five years (e.g. textiles and electrical equipment) to more than 20 years (e.g. construction materials, industrial machinery). Plastic consumption differs among countries and communities, with some form of plastic having made its way into most people's lives. North America (i.e.

6724-644: Was estimated at over 150 million tonnes in 2015. The plastic industry includes the global production, compounding , conversion and sale of plastic products. Although the Middle East and Russia produce most of the required petrochemical raw materials, the production of plastic is concentrated in the global East and West. The plastic industry comprises a huge number of companies and can be divided into several sectors: Between 1950 and 2017, 9.2 billion tonnes of plastic are estimated to have been made, with more than half this having been produced since 2004. Since

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