Bioplastics are types of plastic made from renewable materials like plants and other living things. They are important in the bioeconomy and circular economy, which focus on using resources wisely and reducing waste. Traditional plastics made from oil are often mixed with bioplastics to create products that have some bioplastic content. This can make it hard to tell the difference between bioplastics and other plastics.

Bioplastics can be made in several ways:
1. From plant waste, such as straw, wood chips, sawdust, and food scraps.
2. Using biomass, which is material from living organisms.

One benefit of bioplastics is that they do not rely on fossil fuels, which are limited and unevenly spread across the world. Fossil fuels are linked to environmental problems and political issues related to oil. Bioplastics can use waste materials that are often not used for other purposes. Studies show that some bioplastics have a smaller carbon footprint than traditional plastics when biomass is used for both making the plastic and producing energy. However, other bioplastics may have a larger carbon footprint than traditional plastics.

Whether a plastic is durable or breaks down depends on its molecular structure, not on the source of the material. Some bioplastics, like Bio-PET or biopolyethylene, are strong and long-lasting, similar to traditional plastics. Other bioplastics, such as polylactic acid or polyhydroxyalkanoates, can break down over time. Like traditional plastics, bioplastics should be recycled to reduce pollution. "Drop-in" bioplastics, such as biopolyethylene, can be recycled the same way as regular plastics. However, recycling biodegradable bioplastics is more difficult because it can increase sorting costs and lower the quality of recycled materials. While biodegradation is one way to dispose of biodegradable plastics, recycling is often better for the environment.

Biodegradability can be useful in some uses, like agricultural mulch films. However, whether a bioplastic breaks down depends on its chemical structure. Different bioplastics have different structures, so they may not break down easily in the environment. Some biodegradable plastics are even made from fossil fuels.

In 2018, bioplastics made up about 2% of all plastic produced worldwide (more than 380 million tons). By 2022, the most widely used bioplastics were polylactic acid (PLA) and products made from starch.

Types

Thermoplastic starch is the most commonly used bioplastic, making up about half of the bioplastics market. Simple starch-based bioplastic film can be made at home by heating starch and using a process called solution casting. Pure starch can absorb moisture, making it useful for creating drug capsules in the pharmaceutical industry. However, pure starch-based bioplastic is brittle. Adding materials like glycerol, glycol, or sorbitol makes the starch easier to shape when heated. The properties of the resulting bioplastic can be changed by adjusting the amounts of these added materials. Traditional methods like extrusion, injection molding, compression molding, and solution casting can be used to make starch-based bioplastics. The characteristics of starch bioplastic depend on the balance between two types of starch molecules called amylose and amylopectin. Starch with more amylose usually has better strength but is harder to process because it requires higher heat and has thicker melted material.

Starch-based bioplastics are often mixed with biodegradable polyesters to create materials like starch/polylactic acid, starch/polycaprolactone, or starch/Ecoflex blends. These blends are used in industrial products and can be composted. Other companies, like Roquette, make starch/polyolefin blends that are not biodegradable but have a smaller environmental impact than petroleum-based plastics.

Starch is inexpensive, widely available, and can be grown again. Starch-based films, mainly used for packaging, are made by blending starch with thermoplastic polyesters to create biodegradable and compostable products. These films are used in packaging for items like magazines, bubble wrap, and food bags for baked goods or fruits and vegetables. Composting bags made with these films help collect organic waste. These films can also be used as paper.

Starch-based nanocomposites have been studied extensively and show improved strength, heat resistance, moisture resistance, and ability to block gases.

Cellulose bioplastics are mainly made from cellulose esters, such as cellulose acetate and nitrocellulose, and their derivatives, like celluloid. Cellulose can become thermoplastic after being chemically modified. For example, cellulose acetate is expensive and rarely used for packaging. However, adding cellulose fibers to starch can improve strength, gas permeability, and water resistance because cellulose is less likely to absorb water than starch.

Bioplastics can be made from proteins, such as wheat gluten and casein, which are promising materials for biodegradable polymers. Soy protein is another source being studied. Soy proteins have been used in plastic production for over 100 years, like in the body panels of an early Ford car. However, soy-based plastics are sensitive to water and more expensive, so blending them with biodegradable polyesters helps improve these issues.

Aliphatic bio polyesters include materials like polyhydroxyalkanoates (PHAs), such as poly-3-hydroxybutyrate (PHB), polyhydroxyvalerate (PHV), and polyhydroxyhexanoate (PHH). Polylactic acid (PLA) is a clear plastic made from corn or dextrose. It looks similar to traditional plastics like polystyrene (PS) but is made from plants and breaks down in industrial composting. However, PLA has weaker impact strength, heat resistance, and gas barrier properties compared to non-biodegradable plastics. PLA is used in limited amounts for films, fibers, containers, cups, and bottles. It is also the most common material used in home 3D printers.

The biopolymer poly-3-hydroxybutyrate (PHB) is a polyester made by bacteria using glucose, corn starch, or wastewater. Its properties are similar to the petroplastic polypropylene (PP). PHB production is growing, with industries like the South American sugar industry expanding its use. PHB can be made into a clear film with a melting point above 130 degrees Celsius and is biodegradable without leaving residue.

Polyhydroxyalkanoates (PHAs) are natural polyesters made by bacteria through fermentation of sugar or lipids. These materials are used by bacteria to store energy and are extracted and purified for industrial use. Over 150 different building blocks can be combined to create PHAs with varying properties. PHAs are more flexible and less elastic than other plastics but are biodegradable. They are widely used in the medical industry.

PA 11 is a biopolymer made from natural oil, also called Rilsan B by Arkema. It belongs to a group of technical polymers and is not biodegradable. It has similar properties to PA 12 but uses fewer nonrenewable resources and produces fewer greenhouse gases during production. It is used in high-performance applications like car fuel lines, airbrake tubes, and flexible pipes.

A similar plastic is Polyamide 410 (PA 410), made mostly from castor oil and sold as EcoPaXX by DSM. PA 410 is a high-performance polyamide with a high melting point (about 250°C), low water absorption, and strong resistance to chemicals.

Polyethylene is made from ethylene, which can be produced from ethanol made by fermenting crops like sugarcane or corn. Bio-derived polyethylene is chemically the same as traditional polyethylene, meaning it does not biodegrade but can be recycled. A company in Brazil, Braskem, claims its method of making polyethylene from sugarcane ethanol removes 2.15 tonnes of CO₂ for every tonne of Green Polyethylene produced.

Genetically modified corn is often used in bioplastics. Some bioplastics are made using genetically modified crops or bacteria to improve efficiency.

Polyhydroxyurethanes are made by combining polyamines and cyclic carbonates. Unlike traditional polyurethanes, these materials can be recycled and reprocessed using specific chemical reactions.

Several types of bioplastics have been created from plant and animal fats and oils, including polyurethanes, polyesters, and epoxy resins. These materials have properties similar to petroleum-based plastics. Recent advances in a chemical process called olefin metathesis have opened new possibilities for creating bioplastics.

Environmental impact

Bioplastics are made from materials like starch, cellulose, wood, sugar, and biomass. These materials replace fossil fuels, making bioplastics a more sustainable choice compared to traditional plastics. The environmental effects of bioplastics are often discussed because different factors, such as water use, energy use, deforestation, and biodegradation, are used to measure their "greenness." The main environmental impacts of bioplastics are linked to nonrenewable energy use, climate change, eutrophication, and acidification. Producing bioplastics reduces greenhouse gas emissions and lowers the use of nonrenewable energy. Companies worldwide can improve the environmental sustainability of their products by using bioplastics.

Bioplastics save more nonrenewable energy and release fewer greenhouse gases than conventional plastics. However, they also have negative effects, such as eutrophication and acidification. Eutrophication happens when excess nutrients like nitrates and phosphates from industrial farming enter water bodies, causing harmful algal blooms that create oxygen-depleted zones, harming aquatic life. Acidification occurs when chemical fertilizers used to grow crops for bioplastics increase acidity in the environment.

Bioplastics have lower human and terrestrial ecotoxicity and carcinogenic risks compared to traditional plastics. However, they have higher aquatic ecotoxicity. They also increase stratospheric ozone depletion due to nitrous oxide emissions from fertilizers used in farming. Other minor effects include pesticide use, carbon dioxide emissions from harvesting vehicles, high water use for biomass growth, soil erosion, soil carbon loss, and biodiversity loss. These issues are often linked to land use for bioplastic production, which reduces carbon sequestration and increases carbon costs.

Bioplastics are beneficial because they reduce nonrenewable energy use and greenhouse gas emissions. However, they also harm the environment through land and water use, pesticide and fertilizer use, eutrophication, and acidification. Choosing between bioplastics and conventional plastics depends on which environmental impact is considered most important.

Some bioplastics are made from edible crops, which can compete with food production. These are called "1st generation feedstock bioplastics." "2nd generation feedstock bioplastics" use non-food crops or waste materials, such as used vegetable oil. "3rd generation feedstock bioplastics" use algae as the raw material.

Biodegradation is the process by which enzymes in liquid break down solid materials like plastic. Some bioplastics and conventional plastics with additives can biodegrade. Bioplastics can break down in various environments, such as soil, water, and compost, making them more acceptable than traditional plastics. The structure and composition of bioplastics affect how quickly they biodegrade. Soil and compost environments are more effective for biodegradation because they have diverse microorganisms. Composting helps biodegrade bioplastics efficiently and reduces greenhouse gas emissions. Adding more sugar or increasing temperature in compost can improve biodegradation. Soil environments also support biodegradation but require higher temperatures and longer time. Some bioplastics break down faster in water and marine environments, but this can harm marine and freshwater ecosystems. Therefore, biodegradation in water bodies, which can harm aquatic life and water quality, is a negative environmental impact of bioplastics.

Applications

Bioplastics are not widely used in businesses. Their cost and how well they work are still issues. In Italy, a law passed in 2011 requires shoppers to use biodegradable plastic bags. These bags break down naturally over time. Scientists are also developing electroactive bioplastics that can carry electric current.

Bioplastics are used for items that are used once, like packaging, plates, forks, pots, bowls, and straws. Biopolymers can be used to coat paper instead of the more common petrochemical coatings.

Drop-in bioplastics are the same as those made from fossil fuels but use renewable resources. Examples include bio-PE, bio-PET, bio-propylene, bio-PP, and biobased nylons. These bioplastics are easy to use because current systems can handle them. A dedicated bio-based pathway allows the production of materials that cannot be made through traditional chemical methods. These materials can have special and better properties than those made from fossil fuels.

Bioplastics have been around since the early 1900s. Major improvements happened in the 1980s and 1990s when scientists began making biodegradable plastics from natural sources. The construction industry started paying attention to bioplastics in the late 2000s because of efforts to build greener and the benefits of bioplastics, like better energy use and being biodegradable.

In recent years, bioplastics have improved in strength, cost, and performance. New blends and composites have made them better for construction, from insulation to parts that hold up buildings.

The future for bioplastics in construction is bright. More research and innovation will likely increase their use and improve their quality. As the construction industry becomes more focused on sustainability, bioplastics may become important in making eco-friendly materials.

Bioplastics are a good, flexible option compared to traditional materials. They have environmental and economic benefits. Even though there are still problems with cost and performance, new developments in bioplastic technology could change the construction industry and help create a more sustainable future.

Industry and markets

Throughout the 20th century, chemical companies produced plastics made from organic materials. In 1983, the first company to focus only on bioplastics, called Marlborough Biopolymers, was created. However, Marlborough and other similar companies did not achieve long-term financial success. The first company to succeed in this area was Novamont, an Italian company founded in 1989.

Bioplastics make up less than 1% of all plastics made globally. Most bioplastics do not yet reduce carbon emissions more than the energy needed to produce them. It is estimated that replacing 250 million tons of traditional plastic each year with bioplastics would require 100 million hectares of land, which is about 7% of the world’s arable land. When bioplastics are no longer useful, those designed to be compostable or biodegradable are often thrown into landfills because proper composting facilities or waste sorting systems are not widely available. In landfills, these materials break down without oxygen and release methane, a type of harmful gas.

COPA (Committee of Agricultural Organisation in the European Union) and COGEGA (General Committee for the Agricultural Cooperation in the European Union) have studied the potential uses of bioplastics in various parts of the European economy.

The bioplastics market is growing because of increased demand for sustainable construction materials. This growth creates new economic opportunities for companies that make and sell bioplastics. The estimated value of the bioplastics market in 2024 is 7.41 billion USD. It is predicted to grow to 127.55 billion USD by 2025, with Europe producing the largest share of bioplastics.

History and development of bioplastics

• 1855: An earlier version of linoleum is created.
• 1862: At the Great London Exhibition, Alexander Parkes shows Parkesine, the first thermoplastic. Parkesine is made from nitrocellulose and has good qualities, but it can catch fire easily. (White 1998)
• 1897: Galalith, a bioplastic made from milk, is created by German scientists. It is still used today, mainly in buttons. (Thielen 2014)
• 1907: Leo Baekeland invents Bakelite, which is recognized for its ability to resist heat and electricity. It is used in radios, telephones, kitchen tools, firearms, and other products. (Pathak, Sneha, Mathew 2014)
• 1912: Brandenberger invents Cellophane using cellulose from wood, cotton, or hemp. (Thielen 2014)
• 1920s: Wallace Carothers discovers Polylactic Acid (PLA) plastic. PLA is very expensive to make and is not widely produced until 1989. (Whiteclouds 2018)
• 1925: French scientist Maurice Lemoigne isolates and identifies Polyhydroxybutyrate.
• 1926: Maurice Lemoigne invents polyhydroxybutyrate (PHB), the first bioplastic made from bacteria. (Thielen 2014)
• 1930s: A car made from soybeans is created by Henry Ford. (Thielen 2014)
• 1940-1945: During World War II, plastic production increases because it is used in wartime materials. Government support causes U.S. plastic production (including non-bioplastics) to triple between 1940 and 1945. (Rogers 2005) A 1942 U.S. government film, The Tree in a Test Tube, shows how bioplastics helped the war effort and the economy.
• 1950s: Amylomaize (corn with high amylose content) is bred successfully, and research on commercial bioplastics begins. (Liu, Moult, Long, 2009) Development of bioplastics slows because of low oil prices, but synthetic plastics continue to be made.
• 1970s: The environmental movement leads to more research on bioplastics. (Rogers 2005)
• 1983: Marlborough Biopolymers, the first bioplastics company, is started. It uses a bacteria-based bioplastic called biopal. (Feder 1985)
• 1989: Dr. Patrick R. Gruber finds a way to make PLA from corn. A company called Novamount is created to produce and use bioplastic in many applications. (Whiteclouds 2018; Novamount 2018)
• Late 1990s: BIOTEC develops TP starch and BIOPLAST, leading to BIOFLEX film. BIOFLEX film can be used in blown film extrusion (bags, trash bags, gloves), flat film extrusion (trays, cups, packaging), and injection moulding (cutlery, containers, toys). (Lorcks 1998)
• 1992: A study in Science reports that the plant Arabidopsis thaliana can produce PHB. (Poirier, Dennis, Klomparens, Nawrath, Somerville 1992)
• 2001: Metabolix inc. buys Monsanto’s biopol business (originally Zeneca) to produce bioplastics using plants. (Barber and Fisher 2001)
• 2001: Nick Tucker uses elephant grass to create plastic car parts. (Tucker 2001)
• 2005: Cargill and Dow Chemicals rebrand as NatureWorks and become the leading PLA producer. (Pennisi 2016)
• 2007: Metabolix inc. tests Mirel, a 100% biodegradable plastic made from corn sugar and bacteria. (Digregorio 2009)
• 2012: A bioplastic made from seaweed is developed. Research shows it is one of the most environmentally friendly bioplastics. (Rajendran, Puppala, Sneha, Angeeleena, Rajam 2012)
• 2013: A patent is granted for a bioplastic made from blood and crosslinking agents like sugars and proteins. This bioplastic can be used in tissues, bones, and stem cell delivery. (Campbell, Burgess, Weiss, Smith 2013)
• 2014: A study finds that bioplastics can be made by mixing vegetable waste (like parsley stems and rice hulls) with pure cellulose solutions. (Bayer, Guzman-Puyol, Heredia-Guerrero, Ceseracciu, Pignatelli, Ruffilli, Cingolani, and Athanassiou 2014)
• 2016: An experiment shows that a car bumper meeting regulations can be made from bioplastic using banana peels. (Hossain, Ibrahim, Aleissa 2016)
• 2017: A new idea for bioplastics is proposed using lignocellulosic resources (dry plant matter). (Brodin, Malin, Vallejos, Opedal, Area, Chinga-Carrasco 2017)
• 2018: Developments include Ikea starting industrial production of bioplastics for furniture (Barret 2018), Project Effective working on replacing nylon with bio-nylon (Barret 2018), and the first packaging made from fruit (Barret 2018).
• 2019: Five types of chitin nanomaterials are extracted and tested by the Korea Research Institute of

Testing procedures

To claim that a plastic product is compostable in Europe, it must meet the EN 13432 industrial standard. This standard requires several tests to determine if a product meets specific requirements. These include breaking down physically and visually within 12 weeks, breaking down organic materials into carbon dioxide within 180 days, and ensuring the product does not harm plants or contain harmful heavy metals. In the United States, the ASTM 6400 standard is used, and it has similar requirements.

Some types of plastics, such as starch-based plastics, PLA-based plastics, and certain polyester compounds like succinates and adipates, have passed these standards. However, plastics labeled as photodegradable or Oxo Biodegradable, which rely on additives, do not meet these standards.

The ASTM D 6002 method defined "compostable" as a plastic that breaks down as quickly as other materials already known to compost under traditional definitions. This definition was criticized because it did not require the final product to become compost or humus. In January 2011, the ASTM removed this standard, which had allowed manufacturers to legally label plastics as compostable. The ASTM has not yet replaced this standard.

The ASTM D6866 method measures the amount of carbon in bioplastics that comes from living organisms. Plants take in carbon dioxide from the air, which includes a radioactive form of carbon called carbon-14. Over time, carbon-14 breaks down completely, leaving only non-radioactive carbon-12. Products made from plant material contain more carbon-14 than products made from petroleum. Scientists use a special tool called an accelerator mass spectrometer to measure the percentage of renewable carbon in a material.

Biodegradability and biobased content are different. For example, a bioplastic like high-density polyethylene (HDPE) can be made entirely from renewable sources but may not break down naturally. These plastics still help reduce greenhouse gases when burned for energy because the carbon they contain is considered carbon-neutral, as it originally came from plants.

The ASTM D5511-12 and ASTM D5526-12 are testing methods that follow international standards like ISO DIS 15985 for checking if plastics can biodegrade.