Wikipedia

For other uses, see Plastic (disambiguation).

Plastics are a wide range of synthetic or semisynthetic materials composed primarily of polymers. Their defining characteristic, plasticity, allows them to be molded, extruded, or pressed into a diverse range of solid forms. This adaptability, combined with a wide range of other properties such as low weight, durability, flexibility, chemical resistance, low toxicity, and low-cost production, has led to their widespread use around the world. While most plastics are produced from natural gas and petroleum, a growing minority are produced from renewable resources like polylactic acid.

Between and , 9.2 billion metric tons of plastic are estimated to have been made, with more than half of this amount being produced since . In alone, preliminary s indicate that over 400 million metric tons of plastic were produced worldwide. If global trends in plastic demand continue, it is projected that annual global plastic production will exceed 1.3 billion tons by . The primary uses for plastic include packaging, which makes up about 40% of its usage, and building and construction, which makes up about 20% of its usage.

The Success and dominance of plastics since the early 20th century has had major benefits for mankind, ranging from medical devices to light-weight construction materials. The sewage systems in many countries relies on the resiliency and adaptability of polyvinyl chloride. It is also true that plastics are the basis of widespread environmental concerns, due to their slow decomposition rate in natural ecosystems. Most plastic produced has not been reused. Some is unsuitable for reuse. Much is captured in landfills or as plastic pollution. Particular concern focuses on microplastics. Marine plastic pollution, for example, creates garbage patches. 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 the developing world, the applications of plastic may differ; 42% of India's consumption is used in packaging. 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 , by Leo Baekeland, who coined 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".

Etymology

The term plastic originates from the Ancient Greek πλαστικός (plastikos), which means "capable of being shaped or molded." This is derived from πλαστός (plastos), signifying "molded" or "formed." In contemporary usage, plastic primarily denotes the solid synthetic materials produced through petrochemical manufacturing.

The term plasticity refers to the ability of materials used in plastic manufacturing to deform. This property enables processes such as molding, extrusion, and compression, resulting in various shapes like films, fibers, plates, tubes, bottles, and boxes, among others. In materials science, plasticity has a more specific definition, describing the irreversible change in the form of solid substances under external forces. However, this technical aspect is beyond the scope of this article.[citation needed]

Structure

See also: Polymer

Most plastics consist of organic polymers. The majority of these polymers are composed of chains of carbon atoms, with or without attached oxygen, nitrogen, or sulfur atoms. These chains are made up of numerous repeating units derived from monomers. Each polymer chain typically contains several thousand repeating units. The backbone refers to the segment of the chain that forms the main path, linking together a significant number of repeat units. To modify the properties of a plastic, various molecular groups known as side chains extend from this backbone; these are generally attached to the monomers prior to the linkage that forms the polymer chain. The arrangement of these side chains affects the properties of the polymer.[citation needed]

Classifications

Plastics are typically categorized based on the chemical structure of their polymer backbone and side chains. Key groups in this classification include acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. Additionally, plastics can be classified according to the chemical processes used in their synthesis, such as condensation, polyaddition, and cross-linking. They can also be distinguished by their physical properties, including hardness, density, tensile strength, thermal resistance, and glass transition temperature. Furthermore, plastics may be classified based on their reactions and resistance to various substances and processes, such as organic solvents, oxidation, and ionizing radiation. Other classifications focus on characteristics relevant to manufacturing or product design for specific applications, including thermoplastics, thermosets, conductive polymers, biodegradable plastics, engineering plastics, and elastomers.

Thermoplastics and Thermosetting Polymers

One significant classification of plastics is based on the reversibility of the chemical processes used in their production.

Thermoplastics do not undergo chemical changes in their composition when heated, allowing them to be molded multiple times. Examples include polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC).

Thermosets, or thermosetting polymers, can be molded and shaped only once: after they solidify, they remain permanently in that form. If reheated, thermosets will decompose instead of melting. Notable examples of thermosets include epoxy resin, polyimide, and Bakelite. The vulcanization of rubber illustrates this process; before being heated in the presence of sulfur, natural rubber (polyisoprene) is a sticky, slightly viscous substance, whereas after vulcanization, it transforms into a dry and rigid product.

Thermosets are made up of tightly cross-linked polymers, with cross-links represented as red dots. Elastomers feature loosely cross-linked polymers, which enable the material to stretch when subjected to tensile loads. Thermoplastics consist of non-crosslinked polymers, typically exhibiting a semi-crystalline structure (highlighted in red). They possess a glass transition temperature and are fusible.

Commodity, Engineering, and High-Performance Plastics

Commodity Plastics

About 80% of global plastic production consists of commodity plastics, which are favored for their cost-effectiveness and ease of manufacturing. These plastics are produced in large quantities and are commonly found in everyday items such as packaging, food containers, and household products. Most commodity plastics can be identified by their Resin Identification Codes (RICs), a standardized numbering system established by ASTM International.

Polyethylene terephthalate (PET or PETE)

High-density polyethylene (HDPE or PE-HD)

Polyvinyl chloride (PVC or V)

Low-density polyethylene (LDPE or PE-LD)

Polypropylene (PP)

Polystyrene (PS)

In addition to the six most commonly recognized types listed above, there are other commodity plastics that are mass-produced and widely utilized, including polyurethanes (PURs). PURs are classified as commodity plastics because of their affordability, ease of production, and versatility. However, they do not have Resin Identification Codes (RICs) due to their composition of numerous chemically diverse formulations, such as foams and adhesives.

Packaging accounts for the largest share of commodity plastics, utilizing 146 million metric tons (36% of global production) alone. Beyond packaging, these plastics play a vital role in various other sectors, including agriculture, construction, consumer goods, and healthcare.

While desirable traits such as durability and resistance to biodegradability are beneficial for various applications, they have also resulted in significant environmental challenges. Approximately 8 to 12 million tons of plastic enter the oceans each year, mainly due to mismanaged packaging waste. Commodity plastics contribute to the bulk of this pollution, with global recycling rates remaining alarmingly low (approximately 9% of all plastics are recycled). Additionally, microplastics generated from their degradation pose further threats to ecosystems and human health.

There is a vast array of plastics that extend beyond commodity types, many of which possess remarkable properties.

Global plastic production by polymer type ( )```html

Polymer	Production (Mt)	Percentage of all plastics (%)	Polymer type	Thermal character
Low-density polyethylene (LDPE)	64	15.7	Polyolefin	Thermoplastic
High-density polyethylene (HDPE)	52	12.8	Polyolefin	Thermoplastic
Polypropylene (PP)	68	16.7	Polyolefin	Thermoplastic
Polystyrene (PS)	25	6.1	Unsaturated polyolefin	Thermoplastic
Polyvinyl chloride (PVC)	38	9.3	Halogenated	Thermoplastic
Polyethylene terephthalate (PET)	33	8.1	Condensation	Thermoplastic
Polyurethane (PUR)	27	6.6	Condensation	Thermoset

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Engineering Plastics

Engineering plastics are more durable and are utilized in the production of items such as automobile components, construction materials, and certain machine parts. In some instances, they are polymer blends created by combining various plastics (e.g., ABS, HIPS). Engineering plastics can serve as substitutes for metals in vehicles, reducing weight and enhancing fuel efficiency by 6–8%. Approximately 50% of the volume in modern cars is comprised of plastic, yet this constitutes only 12–17% of the vehicle's total weight.

• Acrylonitrile butadiene styrene (ABS): used in electronic equipment cases such as computer monitors, printers, keyboards, and drainage pipes.
• High-impact polystyrene (HIPS): commonly found in refrigerator liners, food packaging, and vending cups.
• Polycarbonate (PC): utilized in compact discs, eyeglasses, riot shields, security windows, traffic lights, and optical lenses.
• Polycarbonate + acrylonitrile butadiene styrene (PC + ABS): a robust blend of PC and ABS employed in car interiors, exteriors, and mobile device bodies.
• Polyethylene + acrylonitrile butadiene styrene (PE + ABS): a slippery mixture of PE and ABS used for low-duty dry bearings.
• Polymethyl methacrylate (PMMA) (acrylic): found in contact lenses (original "hard" type), various glazing applications known globally by trade names like Perspex, Plexiglas, and Oroglas, as well as fluorescent light diffusers and rear light covers for vehicles. It serves as a base for artistic and commercial acrylic paints when suspended in water with other agents.
• Silicones (polysiloxanes): heat-resistant resins predominantly used as sealants, but also found in high-temperature cooking utensils and as base resins for industrial paints.
• Urea-formaldehyde (UF): an aminoplast offering multi-color options as an alternative to phenolics, used in wood adhesives (for plywood, chipboard, and hardboard) and electrical switch housings.

High-Performance Plastics

High-performance plastics are a subset of polymers that demonstrate superior characteristics compared to commodity and engineering plastics. These materials can endure elevated temperatures, typically exceeding 302°F (150°C), exhibit significant resistance to chemical corrosion and degradation, possess excellent mechanical and electrical properties, and are lightweight and highly versatile.

• Aramids: best known for their use in the manufacture of body armor, this class of heat-resistant and strong synthetic fibers also has applications in aerospace and military and includes Kevlar, Nomex, and Twaron.
• Ultra-high-molecular-weight polyethylenes (UHMWPE): known for their exceptional strength and durability.
• Polyetheretherketone (PEEK): a strong, chemical- and heat-resistant thermoplastic; its biocompatibility allows for use in medical implant applications and aerospace moldings. It is one of the most expensive commercial polymers.
• Polyetherimide (PEI): a high-temperature, chemically stable polymer that resists crystallization.
• Polyimide: a high-temperature plastic used in materials such as Kapton tape.
• Polysulfone (PS): a high-temperature melt-processable resin used in membranes, filtration media, water heater dip tubes, and other high-temperature applications.
• Polytetrafluoroethylene (PTFE): a heat-resistant, low-friction coating used in non-stick surfaces for frying pans, plumber's tape, and water slides.
• Polyamide-imide (PAI): a high-performance engineering plastic extensively utilized in high-performance gears, switches, transmissions, and other automotive components and aerospace parts.
• Polyphenylene sulfide (PPS): known for its extreme chemical resistance, flame retardancy, and thermal stability (up to 428°F).
• Polyethersulfone (PES): recognized for its clarity, high-temperature resistance (up to 392°F), and biocompatibility. Commonly used in medical devices, food-grade equipment, and aerospace lighting.
• Polyvinylidene fluoride (PVDF): a nonreactive thermoplastic fluoropolymer celebrated for its extreme chemical resistance, ultraviolet stability, and piezoelectric properties. It is commonly used in semiconductor tubing, lithium-ion battery binders, and architectural coatings.
• Liquid-crystal polymers (LCPs): a class of polymers that blend the properties of liquids and crystals, known for extreme dimensional stability, low thermal expansion, and high dielectric strength. Commonly used in miniature electronics, fiber-optic cables, and surgical devices.
• Polyimides (PIs): a class of high-performance thermosets capable of operating up to 572°F, known for excellent dielectric properties and radiation resistance. Commonly used in flexible printed circuits, space suit layers, and jet engine components.
• Polybenzimidazole (PBI): exhibits extremely high heat resistance (up to 752°F short-term), low outgassing, and flame resistance. Commonly used in firefighting gear, semiconductor tools, and aerospace thermal shields.
• Bismaleimide (BMI): recognized for its high glass transition temperature (around 482°F) and low moisture absorption. It is commonly used in composite aircraft matrices and military radar systems.
• Cyanate esters: known for their low dielectric loss and space-grade radiation resistance. Frequently used in satellite components and radar antennas.

Amorphous and Crystalline Plastics

Many plastics are completely amorphous, meaning they lack a highly ordered molecular structure. Crystalline plastics have a more regular arrangement of atoms, examples of which include high-density polyethylene (HDPE), polybutylene terephthalate (PBT), and polyether ether ketone (PEEK). Additionally, some plastics possess a molecular structure that is partially amorphous and partially crystalline, allowing them to feature both a melting point and one or more glass transitions (the temperature above which localized molecular flexibility significantly increases). These semi-crystalline plastics encompass polyethylene, polypropylene, polyvinyl chloride, polyamides (nylons), polyesters, and certain polyurethanes.

Conductive Polymers

Main article: Conductive polymer

Intrinsically conducting polymers (ICPs) are organic polymers capable of conducting electricity. Although stretch-oriented polyacetylene has achieved a conductivity of up to 80 kilosiemens per centimeter (kS/cm), this level does not match that of most metals. For instance, copper exhibits a conductivity of several hundred kS/cm.

Biodegradable Plastics and Bioplastics

Biodegradable Plastics

Main article: Biodegradable plastic

Biodegradable plastics are designed to break down when exposed to biological factors, including sunlight, ultraviolet radiation, moisture, bacteria, enzymes, or wind abrasion. Degradation can also occur through insect activity, such as that of waxworms and mealworms. Aerobic degradation necessitates surface exposure, while anaerobic degradation is effective in landfill or composting settings. Some companies create biodegradable additives to enhance biodegradation. Although adding starch powder as a filler can aid in the degradation of certain plastics, it does not ensure complete breakdown. Additionally, some researchers have genetically engineered bacteria to produce fully biodegradable plastics, such as polyhydroxybutyrate (PHB); however, as of now, these remain relatively expensive.

Bioplastics

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Main article: Bioplastic

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While most plastics are produced from petrochemicals, bioplastics are primarily derived from renewable plant materials such as cellulose and starch. The finite nature of fossil fuel reserves, coupled with increasing greenhouse gas emissions largely attributed to the combustion of these fuels, has made the development of bioplastics an expanding field. It is estimated that global production capacity for bio-based plastics reaches 327,000 tonnes annually. In comparison, the global production of polyethylene (PE) and polypropylene (PP), the leading petrochemical-derived polyolefins, was projected to exceed 150 million tonnes.

Plastic industry

The plastic industry encompasses the global production, compounding, conversion, and sale of plastic products. While the Middle East and Russia supply a significant portion of the necessary petrochemical raw materials, plastic production is largely concentrated in regions of the global East and West. This industry consists of numerous companies and can be segmented into various sectors:

Production

Between [year] and [year], 9.2 billion tonnes of plastic are estimated to have been produced, with more than half of this amount generated since [year]. Since the inception of the plastic industry in the [decade], global production has surged, reaching 400 million tonnes per year in [year], up from 381 million metric tonnes in [year] (excluding additives). From the [decade], there was a rapid increase in the use of plastics for packaging, building and construction, as well as in other sectors. If global trends in plastic demand persist, it is projected that by [year], annual global plastic production will exceed 1.1 billion tonnes.

• Polypropylene Plants
• A Slovnaft facility located in Bratislava, Slovakia
• A SOCAR Polymer polypropylene plant situated in Sumgayit, Azerbaijan

Plastics are generated in chemical plants through the polymerization of monomers, which are predominantly derived from petrochemicals. These facilities are typically large and resemble oil refineries, characterized by extensive pipework throughout the site. The size of these plants enables them to benefit from economies of scale. Despite this, the plastic production industry is not highly monopolized; around 100 companies collectively account for 90% of global production. This figure includes a combination of private and state-owned enterprises. Approximately half of all production occurs in East Asia, with China being the largest individual producer. Key international producers include:

```html Global plastic production ``````html Global production 31% 3% 17% 19% 4% 16% 3% 7% ```

• BASF
• Braskem
• DOW Chemical
• ExxonMobil
• LyondellBasell
• Indorama Ventures
• SABIC
• Sibur
• Sinopec
• Shin-Etsu Chemical

Historically, Europe and North America have dominated global plastics production. However, Asia has emerged as a significant producer, with China accounting for 31% of total plastic resin production. Regional differences in plastics production volumes are driven by user demand, the price of fossil fuel feedstocks, and investments in the petrochemical industry. For instance, over US$200 billion has been invested in new plastic and chemical plants in the United States, stimulated by the low cost of raw materials. Similarly, significant investments have been made in the European Union (EU), where the plastics industry employs over 1.6 million people and generates more than 360 billion euros annually. In China, there were over 15,000 plastic manufacturing companies in 2021, generating more than US$366 billion in revenue.

In [year], 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.

Compounding

Plastic is rarely sold as a pure, unadulterated substance; instead, it is blended with various chemicals and materials known as additives. These are introduced during the compounding stage and include substances such as stabilizers, plasticizers, and dyes, which enhance the lifespan, workability, or appearance of the final product. In some instances, different types of plastics are mixed to create a polymer blend, like high-impact polystyrene. While large companies may handle their own compounding before production, some producers outsource this process to third-party specialists known as Compounders.

The compounding of thermosetting plastics is relatively straightforward, as they remain in a liquid state until cured into their final form. In contrast, thermosoftening materials, which are used to manufacture the majority of products, require melting the plastic to incorporate additives. This process involves heating the plastic to temperatures between 150–320 °C (300–610 °F). However, molten plastic is viscous and exhibits laminar flow, which can lead to inadequate mixing. Therefore, compounding is performed using extrusion equipment that provides the necessary heat and mixing to achieve a well-dispersed product.

While the concentrations of most additives are typically quite low, higher levels can be incorporated to produce Masterbatch products. In these products, the additives are concentrated but remain properly dispersed within the host resin. Masterbatch granules can be blended with less expensive bulk polymer, releasing their additives during processing to achieve a homogeneous final product. This approach can be more cost-effective than using a fully compounded material and is especially common for color introduction.

Conversion

Converters, also referred to as processors, are companies or specialists that manufacture finished plastic products using raw materials such as resins, pellets, or films.

• Injection molding: This process involves injecting molten plastic into a mold cavity under high pressure, where the plastic solidifies to form the desired shape.
• Blow molding: This technique entails heating a plastic tube called a parison and inflating it inside a mold to create hollow products such as bottles and toys.
• Rotational molding: This method consists of rotating a mold on two axes while it is heated. Plastic powder is added to the mold, melting and adhering to the walls as it rotates, resulting in thick-walled hollow parts like intermediate bulk containers.
• Casting: This process involves pouring liquid resin into a mold, where it solidifies into a predesigned shape.
• Film blowing: This technique includes heating a polymer and blowing it into a thin, continuous sheet, commonly used for producing polyethylene and polypropylene films for packaging.
• Spinning: This process transforms a polymer melt or solution into continuous strands.
• 3D printing: This method involves layer-by-layer printing of an object following a digital model, utilizing computer-aided design software.

For thermosetting materials, the process differs slightly; the plastics start as liquids and must be cured to produce solid products. However, much of the equipment remains broadly similar.

The most commonly produced plastic consumer products include packaging made from LDPE (such as bags, containers, and food packaging film), containers made from HDPE (such as milk bottles, shampoo bottles, and ice cream tubs), and PET (such as bottles for water and other beverages). Together, these items account for approximately 36% of global plastic usage. Most of these products (such as disposable cups, plates, cutlery, takeaway containers, and carrier bags) are utilized for a very short duration, often less than a day. Plastics are also significantly used in building and construction, textiles, transportation, and electrical equipment, which make up a notable portion of the plastics market. Items made from plastic for these applications typically have longer life spans, ranging from about five years (such as textiles and electrical equipment) to over 20 years (such as construction materials and industrial machinery).

Plastic consumption varies across countries and communities, with some type of plastic integrated into nearly everyone's daily life. North America (encompassing the North American Free Trade Agreement or NAFTA region) represents 21% of global plastic consumption, closely followed by China at 20% and Western Europe at 18%. Both North America and Europe exhibit high per capita plastic consumption, with figures of 94 kg and 85 kg per capita per year, respectively. In contrast, China's per capita consumption is lower at 58 kg per capita per year, but the total consumption is substantial due to its large population.

Gallery

• Water bottles made from PET
• High-density polyethylene (HDPE) is used for sturdy containers; transparent containers are often made of PET.
• Disposable suits can be crafted from non-woven HDPE fabric.
• Plastic mailing envelopes made from HDPE
• A Ziploc bag made from LDPE
• Food wrap made from LDPE
• Metalized polypropylene film is commonly used for snack packaging.
• Kinder Joy shell made from polypropylene
• A polypropylene chair
• Stools made from HDPE
• Expanded polystyrene foam ("Thermocol")
• Extruded polystyrene foam ("Styrofoam")
• Thermocol take-away food container
• Egg tray made from PETE
• A piece of packaging foam made from LDPE
• A kitchen sponge made from polyurethane foam
• Non-stick cookware with Teflon coating
• iPhone 5c, a smartphone with a polycarbonate "unibody" shell
• To withstand extreme water pressure, this 10-meter deep Monterey Bay Aquarium tank has windows made of acrylic glass up to 33 cm thick.
• PVC pipes
• PVC blister pack

Applications

The primary use of plastics is in packaging materials; however, they are also utilized across various sectors, including construction (pipes, gutters, doors, 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 employed in the production of aspheric lenses.

Additives

Additives are chemicals blended into plastics to improve their performance or appearance. They are a significant reason why plastics are so widely used. Plastics consist of chains of polymers, and a variety of chemicals serve as plastic additives. Typically, a randomly chosen plastic product contains about 20 different additives. However, the specific identities and concentrations of these additives are usually not disclosed on the products.

In the EU, over 400 additives are used in high volumes. A global market analysis identified 5,500 additives. All plastics typically contain some polymer stabilizers, which enable them to be melt-processed (molded) without experiencing polymer degradation. Additives in polyvinyl chloride (PVC), commonly used for sanitary plumbing, can account for up to 80% of the total volume. Unadulterated plastic (barefoot resin) is rarely sold.[citation needed]

Leaching Process

Additives can be weakly bound to polymers or react within the polymer matrix. While they are blended into plastics, they remain chemically distinct and may gradually leach out during normal use, in landfills, or after improper disposal in the environment. Additionally, additives can degrade into other compounds that may be either more benign or more toxic. The fragmentation of plastics into microplastics and nanoplastics facilitates the movement of chemical additives far from their original point of use. Once released, some additives and their derivatives can persist in the environment and bioaccumulate in organisms, potentially causing adverse effects on human health and ecosystems. A recent review by the United States Environmental Protection Agency (US EPA) found that among 3,377 chemicals potentially associated with plastic packaging and 906 likely linked to it, 68 were ranked by ECHA as "highest for human health hazards" and another 68 as "highest for environmental hazards".

Recycling

Main article: Plastic recycling

As additives alter the properties of plastics, they must be taken into account during recycling. Currently, nearly all recycling involves merely remelting and reshaping used plastics into new products. Additives pose risks in recycled items due to their challenging removal. When plastic products are recycled, it is highly probable that these additives will be incorporated into the new items. Plastic waste, even when it consists of the same polymer type, contains a mix of various additives in differing quantities. Combining these can result in materials with inconsistent properties, which can deter industrial use. For instance, mixing different colored plastics along with various colorants can yield a discolored or brown material; hence, plastics are typically sorted by both polymer type and color before recycling.

Lack of transparency and reporting throughout the value chain often leads to insufficient awareness regarding the chemical composition of final products. For instance, brominated flame retardants have been found in newly manufactured plastic products. Flame retardants are a category of chemicals utilized in electronic and electrical equipment, textiles, furniture, and construction materials, which should not be present in food packaging or childcare items. A recent study identified brominated dioxins as unintentional contaminants in toys made from recycled plastic electronic waste containing brominated flame retardants. Brominated dioxins exhibit toxicity akin to that of chlorinated dioxins, potentially causing harmful developmental impacts, adversely affecting the nervous system, and disrupting endocrine system functions.

Health Effects

Plastics have become widespread partly due to their relatively benign nature. They are not acutely toxic primarily because they are insoluble and/or indigestible due to their high molecular weight. Additionally, their degradation products are seldom toxic. However, this is not the case for some additives, which typically have a lower molecular weight.

Controversies surrounding plastics often involve their additives, many of which can be harmful. For instance, certain flame retardants, such as octabromodiphenyl ether and pentabromodiphenyl ether, are deemed unsuitable for food packaging. Other harmful additives, including cadmium, chromium, lead, and mercury (which are regulated under the Minamata Convention on Mercury), have been banned in many jurisdictions due to their previous use in plastic production. Despite this, they are still frequently detected in some plastic packaging, including food products.[citation needed]

Underdeveloped Nations

Additives can create significant issues when waste is incinerated, particularly in uncontrolled environments or in low-technology incinerators, which are prevalent in many developing countries. Incomplete combustion may result in the release of harmful substances, including acid gases and ash that can harbor persistent organic pollutants (POPs) like dioxins.

Several additives identified as hazardous to human health and the environment are subject to international regulation. The Stockholm Convention on Persistent Organic Pollutants is a global treaty aimed at protecting human health and the environment from chemicals that remain stable in the environment for extended periods, become widely dispersed, accumulate in the fatty tissues of humans and wildlife, and pose harmful effects on human health or the environment. The use of bisphenol A (BPA) in plastic baby bottles is banned in many regions worldwide, although it remains unregulated in some low-income countries.

Animals

Plasticosis, a newly identified disease caused by the ingestion of plastic waste, was discovered in seabirds. Affected birds exhibited scarred and inflamed digestive tracts, impairing their ability to digest food. "When birds ingest small pieces of plastic, it inflames the digestive tract. Over time, the persistent inflammation causes tissues to become scarred and distorted, affecting digestion, growth, and survival."

Types of Additives

```html Example compounds Share of global additive production (by weight) ``````html Plasticizers 10–70 Plastics can be brittle; adding a small amount of plasticizer enhances durability, while significant additions increase flexibility. Phthalates are the primary class of plasticizers, with safer alternatives including adipate esters (DEHA, DOA) and citrate esters (ATBC and TEC). Approximately 80–90% of global production is utilized in PVC, with much of the remainder used in cellulose acetate. For most applications, loading levels range from 10 to 35%, with higher loadings used for plastisols. 34% Flame retardants 1–30 As petrochemicals, most plastics are highly flammable; flame retardants help mitigate this risk. Common types include brominated flame retardants and chlorinated paraffins. Non-chlorinated organophosphates are more environmentally friendly, though often less efficient. 13% Heat stabilizers 0.3-5 Heat stabilizers prevent degradation caused by heat. Traditionally, these have been based on lead, cadmium, and tin, but modern alternatives include barium/zinc mixtures and calcium stearate, along with various synergistic compounds. They are almost exclusively used in PVC. 5% Fillers 0–50 Fillers serve as bulking agents, altering appearance and mechanical properties while potentially reducing costs. Common fillers include calcium carbonate ("chalk"), talc, glass beads, and carbon black, as well as reinforcing fillers like carbon fiber. Most opaque plastics contain fillers, and higher concentrations may also provide UV protection. 28% Impact modifiers 10–40 Impact modifiers enhance the toughness and damage resistance of plastics. ``````html

Typically, some other elastomeric polymers, such as rubbers and styrene copolymers, are used for PVC.

• Antioxidants 0.05–3% - Protects against degradation during processing. Examples: Phenols, phosphite esters, certain thioethers. The most widely used type of additives; all plastics will contain polymer stabilizers of some sort.
• Colorants 0.001-10% - Imparts color. Numerous dyes or pigments.
• Lubricants 0.1-3% - Assist in forming/molding the plastic, includes processing aids (or flow aids), release agents, slip additives. Hazardous PFASs, paraffin wax, wax esters, metal stearates (i.e., zinc stearate), long-chain fatty acid amides (oleamide, erucamide). Very common; all examples form a coating between the plastic and machine parts during production. Reduces pressure and power usage in the extruder, as well as imperfections.
• Light stabilizers 0.05–3% - Protects against UV damage. Examples: HALS, UV blockers, and quenchers. Normally only used for items intended for outdoor use.
• Other Various - Antimicrobials, antistatics, blowing agents, nucleating agents, clarifying agents.

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Health effects

Plastics themselves have low toxicity due to their insolubility in water and high molecular weight, making them biochemically inert. However, additives in plastic products can pose greater health risks. For instance, plasticizers like adipates and phthalates are commonly added to brittle plastics such as PVC to enhance flexibility, but traces of these compounds can leach out from the products. Due to concerns regarding the effects of such leachates, the EU has restricted the use of DEHP (di-2-ethylhexyl phthalate) and other phthalates in certain applications, while the US has limited the use of DEHP, DPB, BBP, DINP, DIDP, and DnOP in children’s toys and childcare items through the Consumer Product Safety Improvement Act. Additionally, some compounds leaching from polystyrene food containers have been implicated in hormone disruption and are suspected human carcinogens. Other chemicals of potential concern include alkylphenols.

Although finished plastic may be non-toxic, the monomers used to produce its parent polymers can be toxic. In certain instances, trace amounts of these chemicals may remain trapped in the product unless appropriate processing is performed. For instance, the World Health Organization's International Agency for Research on Cancer (IARC) has identified vinyl chloride, the precursor to PVC, as a human carcinogen.

Bisphenol A (BPA)

Certain plastic products break down into chemicals that possess estrogenic activity. The primary component of polycarbonates, bisphenol A (BPA), acts as an estrogen-like endocrine disruptor that can leach into food. Research published in Environmental Health Perspectives indicates that BPA leached from the linings of tin cans, dental sealants, and polycarbonate bottles may contribute to increased body weight in the offspring of lab animals. A more recent animal study suggests that even low-level exposure to BPA may result in insulin resistance, potentially leading to inflammation and heart disease. As of January, the Los Angeles Times reported that the US Food and Drug Administration (FDA) is allocating $30 million to investigate potential links between BPA and cancer. Bis(2-ethylhexyl) adipate, found in PVC-based plastic wrap, is also concerning, along with the volatile organic compounds that contribute to the new car smell. The EU has enacted a permanent ban on the use of phthalates in toys. In [year], the US government prohibited certain types of phthalates commonly used in plastics.

Environmental effects

The chemical structure of most plastics makes them durable and resistant to many natural degradation processes. As a result, these materials can persist for centuries or longer, similar to how naturally occurring substances like amber have shown significant longevity.clarification needed

Estimates vary regarding the amount of plastic waste generated over the past century. One estimate suggests that one billion tons of plastic waste have been discarded since the 1950s. Other estimates indicate that humans have produced a total of 8.3 billion tons of plastic, of which 6.3 billion tons is waste, with only 9% being recycled.

It is estimated that this waste comprises 81% polymer resin, 13% polymer fibers, and 32% additives. In total, over 343 million tons of plastic waste were generated, with 90% consisting of post-consumer plastic waste (which includes industrial, agricultural, commercial, and municipal plastic waste). The remainder comprises pre-consumer waste from resin production and the manufacturing of plastic products (such as materials rejected due to unsuitable color, hardness, or processing characteristics).

The Ocean Conservancy reported that China, Indonesia, the Philippines, Thailand, and Vietnam collectively dump more plastic into the sea than all other countries combined. The Yangtze, Indus, Yellow, Hai, Nile, Ganges, Pearl, Amur, Niger, and Mekong rivers "transport 88% to 95% of the global [plastics] load into the sea."[verify quote punctuation]

The presence of plastics, particularly microplastics, in the food chain is on the rise. Microplastics were first observed in the guts of seabirds in the 1960s, and since then, their concentrations have continued to increase. The long-term effects of plastics in the food chain remain poorly understood. In 2015, it was estimated that 10% of modern waste consisted of plastic, although estimates can vary by region. Meanwhile, plastic accounts for 50% to 80% of debris in marine environments. Additionally, plastic is frequently used in agriculture, with more plastic found in soil than in oceans. The presence of plastic in the environment negatively impacts ecosystems and human health.

Research on environmental impacts has generally concentrated on the disposal phase. However, plastic production also contributes significantly to environmental, health, and socioeconomic issues.

Before the Montreal Protocol, CFCs were widely used in the production of plastic polystyrene, which contributed to the depletion of the ozone layer.

Efforts to minimize the environmental impact of plastics may include reducing plastic production and usage, implementing waste management and recycling policies, and proactively developing and deploying alternatives to plastics, particularly for sustainable packaging.[citation needed]

Microplastics

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This section is an excerpt from Microplastics.

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Microplastics are defined as "synthetic solid particles or polymeric matrices, with either regular or irregular shapes, ranging in size from 1 μm to 5 mm, of primary or secondary manufacturing origin, and are insoluble in water."

Microplastics contribute to pollution by infiltrating natural ecosystems through various sources such as cosmetics, clothing, construction, renovation, food packaging, and industrial activities.

The term microplastics refers to small plastic particles that differ from larger, non-microscopic plastic waste. There are two recognized classifications of microplastics. Primary microplastics consist of plastic fragments or particles that are 5.0 mm or smaller prior to entering the environment. This category includes microfibers from clothing, microbeads, plastic glitter, and plastic pellets (also known as nurdles). Secondary microplastics are generated from the degradation of larger plastic products due to natural weathering processes after they have been released into the environment. Common sources of secondary microplastics include water and soda bottles, fishing nets, plastic bags, microwave containers, tea bags, and tire wear.

Both types are known to persist in the environment at elevated levels, especially in aquatic and marine ecosystems, where they contribute to water pollution.

Approximately 35% of all ocean microplastics originate from textiles or clothing, primarily due to the erosion of polyester, acrylic, or nylon-based garments, particularly during washing. Additionally, microplastics accumulate in both the air and terrestrial ecosystems, with airborne microplastics detected in various locations, both indoors and outdoors.

Due to the slow degradation of plastics, which can take hundreds to thousands of years, microplastics have a significant likelihood of being ingested, incorporated into, and accumulating in the bodies and tissues of various organisms. Additionally, the toxic chemicals originating from both the ocean and runoff have the potential to biomagnify up the food chain. In terrestrial ecosystems, microplastics have been shown to diminish the viability of soil ecosystems. As of now, the cycle and movement of microplastics in the environment remain not fully understood.

Microplastics can degrade into smaller nanoplastics via chemical weathering, mechanical breakdown, and even during the digestive processes of animals. Nanoplastics, a subset of microplastics, measure less than 1 μm (1 micrometer or 1,000 nm). Due to their size, nanoplastics are not visible to the naked eye.

Plastic Decomposition

Main article: Polymer degradation

Plastics degrade through various processes, with photo-oxidation being the most significant. The chemical structure of the polymers plays a crucial role in determining their fate. In marine environments, the degradation of plastics takes considerably longer due to the saline conditions and the cooling effect of the sea, which contributes to the persistence of plastic debris. Recent studies, however, have indicated that plastics in the ocean break down faster than previously believed, influenced by exposure to sunlight, rain, and other environmental factors, leading to the release of toxic substances like bisphenol A. Nevertheless, the increasing volume of plastics in the ocean has resulted in a slowdown of decomposition. The Marine Conservancy has estimated the decomposition rates of various plastic products: a foam plastic cup is anticipated to take 50 years, a plastic beverage holder about 400 years, a disposable diaper approximately 450 years, and fishing line up to 600 years to degrade.

Scientific research has identified microbial species that can degrade plastics, some of which may be beneficial for the disposal of specific types of plastic waste.

• A team of Japanese scientists studying ponds containing wastewater from a nylon factory discovered a strain of Flavobacterium that can digest certain byproducts of nylon 6 manufacture, such as the linear dimer of 6-aminohexanoate. Nylon 4 (polybutyrolactam) can be degraded by the ND-10 and ND-11 strains of Pseudomonas sp. found in sludge, resulting in GABA (γ-aminobutyric acid) as a byproduct.
• Several species of soil fungi can consume polyurethane, including two species of the Ecuadorian fungus Pestalotiopsis, which can digest polyurethane both aerobically and anaerobically (such as in landfill conditions).
• Methanogenic microbial consortia are capable of degrading styrene, utilizing it as a carbon source. Pseudomonas putida can convert styrene oil into various biodegradable plastics, specifically biodegradable polyhydroxyalkanoates.
• Microbial communities isolated from soil samples mixed with starch have demonstrated the ability to degrade polypropylene.
• The fungus Aspergillus fumigatus is effective in degrading plasticized PVC.: 45–46  Phanerochaete chrysosporium has been grown on PVC in mineral salt agar.: 76  Additionally, P. chrysosporium, Lentinus tigrinus, A. niger, and A. sydowii can effectively degrade PVC.: 122 
• Phenol-formaldehyde, commonly known as Bakelite, is degraded by the white rot fungus P. chrysosporium.
• Acinetobacter has been found to partially degrade low-molecular-weight polyethylene oligomers. In combination, Pseudomonas fluorescens and Sphingomonas can degrade over 40% of the weight of plastic bags in less than three months. The thermophilic bacterium Brevibacillus borstelensis (strain 707) was isolated from soil and is capable of using low-density polyethylene as the sole carbon source when incubated at 50 °C. Pre-exposure of the plastic to ultraviolet radiation breaks chemical bonds and aids biodegradation; the longer the UV exposure, the more enhanced the degradation.
• Hazardous molds have been discovered aboard space stations that can degrade rubber into a digestible form.
• Various species of yeasts, bacteria, algae, and lichens have been found colonizing synthetic polymer artifacts in museums and archaeological sites.
• In the plastic-polluted waters of the Sargasso Sea, bacteria that consume various types of plastic have been identified; however, their effectiveness in cleaning up toxins as opposed to merely releasing them into the marine microbial ecosystem remains unknown.
• Plastic-eating microbes have also been found in landfills.
• Nocardia has the ability to degrade PET with an esterase enzyme.
• The fungus Geotrichum candidum, native to Belize, has been found to consume the polycarbonate plastic used in CDs.
• Futuro houses are constructed from fiberglass-reinforced polyesters, polyester-polyurethane, and PMMA. One such house was found to be adversely affected by Cyanobacteria and Archaea.

Recycling

This section is an excerpt from plastic recycling.

Plastic recycling involves converting plastic waste into new products. This process can help reduce reliance on landfills, conserve resources, and shield the environment from plastic pollution and greenhouse gas emissions. However, recycling rates for plastics remain lower compared to other recyclable materials like aluminum, glass, and paper. Since plastic production began, approximately 6.3 billion tonnes of plastic waste have been generated, with only 9% recycled and about 1% recycled multiple times. Of the rest, 12% was incinerated, while 79% was either sent to landfills or released into the environment, contributing to pollution.

Nearly all plastic is non-biodegradable, and without recycling, it disperses throughout the environment, causing plastic pollution. For instance, as of now, around 8 million tonnes of waste plastic enter the oceans each year, harming marine ecosystems and contributing to the formation of ocean garbage patches.

Almost all recycling is mechanical and involves melting and reforming plastics into new products. This process can cause polymer degradation at the molecular level and requires waste to be sorted by color and polymer type before processing, which is often complicated and costly. Mistakes in sorting can lead to materials with inconsistent properties, making them less appealing to the industry. While filtration in mechanical recycling helps reduce microplastic release, even the most advanced filtration systems cannot entirely prevent microplastics from entering wastewater.

In feedstock recycling, waste plastic is transformed back into its basic chemicals, which can then be used to produce new plastic. This process requires significant energy and capital investment. Alternatively, plastic can be incinerated as a substitute for fossil fuels in energy recovery facilities or biochemically converted into valuable chemicals for industrial use. In certain countries, incineration is the primary method of plastic waste disposal, especially where landfill diversion policies are enforced.

Plastic recycling ranks low in the waste hierarchy, indicating that reduction and reuse are more effective and sustainable long-term solutions.

It has been advocated since the early 1970s,but due to economic and technical challenges, it did not significantly impact the management of plastic waste until the late s.

Pyrolysis Process

When heated above 500 °C (932 °F) in the absence of oxygen (a process known as pyrolysis), plastics can be decomposed into simpler hydrocarbons that serve as feedstocks for the production of new plastics. These hydrocarbons can also be utilized as fuels.

Greenhouse Gas Emissions

According to the Organisation for Economic Co-operation and Development, plastic contributed greenhouse gases equivalent to 1.8 billion tons of carbon dioxide (CO2) to the atmosphere, accounting for 3.4% of global emissions. They predict that by 2030, plastic could emit 4.3 billion tons of greenhouse gas annually. The impact of plastics on global warming is complex. Plastics are primarily made from fossil gas or petroleum; therefore, their production generates additional fugitive methane emissions associated with fossil fuel extraction. Moreover, a significant portion of the energy used in plastic production comes from non-renewable sources, such as the high temperatures generated from burning fossil gas. However, plastics can also help mitigate methane emissions, for instance, through packaging that reduces food waste.

A study found that, compared to glass and aluminum, plastic may actually have a less negative effect on the environment, making it possibly the best option for food packaging and other common uses. The study noted that "replacing plastics with alternatives is worse for greenhouse gas emissions in most cases," and European researchers found that "in 15 of the 16 applications, a plastic product incurs fewer greenhouse gas emissions than their alternatives."

Reducing Plastic Production as a Climate Solution

In a historic first, nearly every country engaged in discussions not only about recycling but also about reducing plastic production. This is an essential part of the solution to the climate change crisis, as plastic is responsible for 3-5% of emissions, according to the United Nations and the US Lawrence Berkeley National Laboratory, and this figure could potentially triple. One contributing factor is that burning plastics releases black carbon, which has a global warming potential up to 5,000 times greater than that of CO2.

Production of Plastics

The production of plastics from crude oil requires between 7.9 and 13.7 kWh/lb, considering the average efficiency of US utility stations at 35%. In contrast, the manufacturing of silicon and semiconductors for modern electronics is even more energy-intensive, with energy consumption ranging from 29.2 to 29.8 kWh/lb for silicon and approximately 381 kWh/lb for semiconductors. This energy demand significantly exceeds that of many other materials. For instance, producing iron from iron ore consumes 2.5-3.2 kWh/lb; glass from sand requires 2.3–4.4 kWh/lb; steel from iron demands 2.5–6.4 kWh/lb; and paper from timber uses 3.2–6.4 kWh/lb.

Incineration of Plastics

Burning plastics at very high temperatures efficiently breaks down many toxic components, such as dioxins and furans. This method is commonly employed in municipal solid waste incineration. Municipal solid waste incinerators typically treat the flue gas to further reduce pollutants, which is essential because uncontrolled incineration of plastic can release carcinogenic polychlorinated dibenzo-p-dioxins. In contrast, open-air burning of plastic occurs at lower temperatures and usually emits these toxic fumes.

In the European Union, municipal waste incineration is regulated by the Industrial Emissions Directive, which mandates a minimum temperature of 850 °C for a duration of at least two seconds.

Facilitation of Natural Degradation

The bacterium Blaptica dubia is believed to aid in the degradation of commercial polystyrene. This biodegradation appears to take place in certain plastic-degrading bacteria residing in the gut of cockroaches, and the byproducts of this process have been detected in their feces as well.

History

For a chronological guide, see the Timeline of plastic development.

The evolution of plastics has transitioned from the use of naturally occurring materials (e.g., gums and shellac) to chemically modified materials (e.g., natural rubber, cellulose, collagen, and milk proteins), and ultimately to entirely synthetic plastics (e.g., Bakelite, epoxy, and PVC). Early plastics were derived from organic polymers like egg and blood proteins. Around 1600 BC, Mesoamericans utilized natural rubber for making balls, bands, and figurines. In the Middle Ages, treated cattle horns were employed as windows for lanterns.[citation needed] To replicate the properties of horns, materials were created by treating milk proteins with lye. The nineteenth century saw significant advancements in the field of chemistry during the Industrial Revolution, leading to numerous material innovations. The development of plastics gained momentum with Charles Goodyear's discovery of vulcanization, which hardened natural rubber.

Parkesine, invented by Alexander Parkes and patented the following year, is considered the first man-made plastic. It was produced from cellulose (the primary component of plant cell walls) treated with nitric acid as a solvent. The resulting product (commonly referred to as cellulose nitrate or pyroxilin) could be dissolved in alcohol and hardened into a transparent and elastic material that could be molded when heated. By incorporating pigments into the mixture, it could be made to resemble ivory. Parkesine was unveiled at the International Exhibition in London, where it earned Parkes a bronze medal.

The world's first fully synthetic plastic was Bakelite, invented in New York by Leo Baekeland, who coined the term plastics. Many chemists have contributed to the materials science of plastics, including Nobel laureate Hermann Staudinger, known as "the father of polymer chemistry," and Herman Mark, referred to as "the father of polymer physics." After World War I, advancements in chemistry led to a surge of new forms of plastics, with mass production commencing in the 1920s and 1930s. Among the earliest examples of this new wave of polymers were polystyrene (first produced by BASF in the 1920s) and polyvinyl chloride (initially created in the 1870s but commercially produced in the late 1920s). In 1943, Durite Plastics, Inc., became the first manufacturer of phenol-furfural resins. In 1933, polyethylene was discovered by Imperial Chemical Industries (ICI) researchers Reginald Gibson and Eric Fawcett.

The discovery of polyethylene terephthalate (PETE) is credited to employees of the Calico Printers' Association in the UK in 1941; it was licensed to DuPont for the US and ICI otherwise, and as one of the few plastics suitable as a replacement for glass in many circumstances, it resulted in widespread use for bottles in Europe. In 1954, polypropylene was discovered by Giulio Natta and began to be manufactured in 1957. Also in 1957, expanded polystyrene (used for building insulation, packaging, and cups) was invented by Dow Chemical. Since the 1960s, plastic production has surged with the advent of polycarbonate and HDPE, widely used in various products. In the 1970s and 1980s, plastic recycling and the development of biodegradable plastics began to flourish to mitigate environmental impacts. From the 1990s to the present, bioplastics from renewable sources and awareness of microplastics have spurred extensive research and policies to control plastic pollution.

Policy

See also: Global plastic pollution treaty

Work is currently underway to develop a global treaty on plastic pollution. On March 2, UN Member States voted at the resumed fifth UN Environment Assembly (UNEA-5.2) to establish an Intergovernmental Negotiating Committee (INC) with the mandate of advancing a legally binding international agreement on plastics. The resolution is entitled "End plastic pollution: Towards an international legally binding instrument." The mandate specifies that the INC must begin its work by the end of [insert year] with the goal of "completing a draft global legally binding agreement by the end of [insert year]."

See also

• American Recyclable Plastic Bag Alliance – A lobby group representing manufacturers and recyclers
• Corn construction – The use of corn (maize) in building materials
• Light activated resin – A resin that cures upon exposure to specific wavelengths of lightPages displaying short descriptions of redirect targets
• Organic light emitting diode – A diode that emits light from organic compoundsPages displaying short descriptions of redirect targets
• Plastic film – A thin, continuous polymer material
• Plastic pollution – The accumulation of plastic in natural ecosystems
• Plastics engineering – A field of engineering focused on the study of polymer materialsPages displaying short descriptions of redirect targets
• Plasticulture – The application of plastic materials in agriculture
• Plastisphere – Plastic debris suspended in water, along with organisms that inhabit it
• Refill (scheme) – An environmental campaign in BritainPages displaying short descriptions of redirect targets
• Roll-to-roll processing
• Self-healing plastic – Materials that can repair themselvesPages displaying short descriptions of redirect targets
• Thermal cleaning – Techniques for industrial cleaning
• Thermoforming – A manufacturing process to mold plastic using heat
• Timeline of materials technology – ToolsPages displaying short descriptions with no spaces

Malleable Plastic

• Plastic arts – Arts that involve the physical manipulation of materials.
• Plastic ratio – A number, approximately 1.

References

• Substantial parts of this text originated from An Introduction to Plastics v1.0 [usurped] by Greg Goebel (March 1) which is in the public domain.

Sources

• This article includes content from a freely licensed work, under CC BY-SA 3.0 IGO (license statement/permission). The text is sourced from Drowning in Plastics – Marine Litter and Plastic Waste Vital Graphics, United Nations Environment Programme.

Further reading

• Hopmann, Christian; Greif, Helmut; Wolters, Leo (December 8, ). Training in Plastics Technology. Carl Hanser Verlag GmbH & Company KG. ISBN 978-1-935-5.
• Fink, Johannes Karl (). Future Trends in Modern Plastics. Wiley. ISBN 978-1-394-9.
• Li, Zibiao; Lim, Jason Y. C.; Wang, Chen-Gang (February 21, ). Circularity of Plastics: Sustainability, Emerging Materials, and Valorization of Waste Plastic. Elsevier. ISBN 978-0-323-2.