Bioplastics are types of plastic made from renewable sources like plants and other living things. In systems that reuse resources, bioplastics are important. Traditional plastics made from oil are often mixed with bioplastics to create products that partly use bioplastics. This makes it hard to tell the difference between bioplastics and other plastics.

Bioplastics can be made in several ways:

One benefit of bioplastics is that they do not rely on oil and gas, which are limited and unevenly spread around the world. These resources are linked to environmental issues and political problems. Bioplastics can use materials that are usually wasted, such as straw, wood chips, sawdust, and food scraps. Studies show that some bioplastics may have a smaller carbon footprint than traditional plastics if they use biomass for both making the plastic and producing energy. However, other bioplastics may have a larger carbon footprint than traditional plastics.

Whether a plastic breaks down or lasts a long time depends on its chemical structure, not on whether it comes from plants or oil. Both long-lasting bioplastics, like Bio-PET or biopolyethylene (similar to traditional plastics), and bioplastics that can break down, like polylactic acid or polyhydroxyalkanoates, exist. Like traditional plastics, bioplastics should be recycled to reduce pollution. Some bioplastics, such as biopolyethylene, can be recycled in the same ways as traditional plastics. Recycling biodegradable bioplastics is harder because it may increase sorting costs and lower the quality of recycled materials. However, recycling through mechanical or chemical methods is often better for the environment than relying on biodegradation.

Biodegradability can be useful in some uses, like farming mulch, but breaking down is not simple. Whether a plastic breaks down depends on its chemical structure, and different bioplastics have different structures. This means bioplastics may not break down easily in the environment. Also, biodegradable plastics can be made from oil and gas.

In 2018, bioplastics made up about 2% of all plastic produced worldwide (over 380 million tons). In 2022, the most important types of bioplastics were PLA and products made from starch.

Types

Thermoplastic starch is the most commonly used bioplastic, making up about 50% of the bioplastics market. Simple starch-based bioplastic film can be made at home by heating starch to make it soft and then casting it into a film. Pure starch can absorb moisture, which makes it useful for making drug capsules. However, pure starch is brittle. Adding materials like glycerol, glycol, or sorbitol makes the starch more flexible and easier to shape when heated. The properties of the final product 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 bioplastics from starch. The characteristics of starch bioplastic depend on the balance between two types of starch molecules called amylose and amylopectin. Starch with more amylose 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, such as Roquette, make starch/polyolefin blends that are not biodegradable but have a smaller environmental impact than traditional plastics. Starch is inexpensive, widely available, and can be grown again. Starch-based films, often used for packaging, are made by combining starch with thermoplastic polyesters to create biodegradable and compostable products. These films are used in packaging for magazines, bubble wrap, and food items like bakery bags or fruit and vegetable bags. Composting bags made from these films help collect organic waste. These films can also be used as paper. Starch-based nanocomposites, which include tiny particles, improve strength, heat resistance, moisture resistance, and ability to block gases.

Cellulose bioplastics include materials like cellulose acetate and nitrocellulose, as well as their derivatives, such as celluloid. Cellulose can become thermoplastic when chemically altered. For example, cellulose acetate is expensive and rarely used for packaging. However, adding cellulosic fibers to starch improves strength, gas permeability, and water resistance because these fibers are less likely to absorb water than starch. Bioplastics can also be made from proteins, such as wheat gluten and casein, which are promising materials for biodegradable plastics. Soy protein is another source of bioplastic. Soy proteins have been used in plastic production for over 100 years, such as in body panels of early Ford cars. However, soy-based plastics are sensitive to water and costly. Mixing soy protein with biodegradable polyesters improves 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 sold in granules and used for films, fibers, containers, cups, and bottles. It is also the most common material for 3D printing filaments. PHB is a polyester made by bacteria that process glucose, corn starch, or wastewater. Its properties are similar to polypropylene (PP). PHB production is growing, with industries like sugar production in South America expanding its use. PHB can be made into transparent films with a melting point above 130°C and is biodegradable without leaving residue.

Polyhydroxyalkanoates (PHAs) are made naturally by bacteria through fermentation of sugars or lipids. These materials are used by bacteria to store energy. In industrial production, PHAs are extracted and purified by controlling fermentation conditions. Over 150 different building blocks can be combined to create PHAs with varied properties. PHAs are more flexible and less elastic than other plastics and are biodegradable. They are widely used in medical applications. PA 11 is a biopolymer made from natural oil, also known as Rilsan B by Arkema. It belongs to a group of technical polymers and is not biodegradable. Its properties are similar to PA 12, but it produces fewer greenhouse gases and uses fewer nonrenewable resources. It has better heat resistance than PA 12 and is used in high-performance applications like car fuel lines, air brake tubes, and sports shoes. A similar plastic, Polyamide 410 (PA 410), is made from 70% castor oil and is called EcoPaXX by DSM. It has a high melting point (about 250°C), resists moisture, and is resistant to chemicals.

The basic unit of polyethylene is ethylene, which is similar to ethanol. Ethanol can be made by fermenting agricultural materials like sugarcane or corn. Bio-based polyethylene is chemically the same as traditional polyethylene, meaning it does not biodegrade but can be recycled. Braskem, a Brazilian company, 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. Under bioplastics manufacturing, the "plant factory" model uses genetically modified crops or bacteria to improve efficiency. Combining polyamines and cyclic carbonates creates polyhydroxyurethanes. Unlike traditional polyureth

Environmental impact

Bioplastics are made from materials like starch, cellulose, wood, sugar, and biomass. These materials replace fossil fuels used to make traditional plastics. This makes bioplastics a more sustainable choice because they help reduce harm to the environment. However, the environmental effects of bioplastics are debated because different factors, such as water use, energy use, and how well they break down, are used to measure their "greenness." Scientists often group the environmental effects of bioplastics into categories like nonrenewable energy use, climate change, eutrophication, and acidification. Producing bioplastics uses less nonrenewable energy and lowers greenhouse gas emissions compared to traditional plastics. Companies worldwide can improve the environmental friendliness of their products by using bioplastics.

Bioplastics save more nonrenewable energy and release fewer greenhouse gases than traditional plastics. However, they also cause problems like eutrophication and acidification. Eutrophication happens when too many nutrients, such as nitrates and phosphates, enter water bodies. This leads to harmful algae growth, which uses up oxygen and harms aquatic life. Acidification occurs when chemicals in the environment make water more acidic. These issues are partly caused by using chemical fertilizers to grow crops used for bioplastics.

Bioplastics have some benefits. They cause less harm to humans and land compared to traditional plastics. However, they are more harmful to water ecosystems. Bioplastics also increase the release of gases that harm the ozone layer, such as nitrous oxide. This happens when fertilizers are used during farming. Other effects include using pesticides on crops, releasing carbon dioxide from farming machines, and using a lot of water for growing biomass. These actions can lead to soil erosion, loss of soil carbon, and reduced biodiversity. These problems often happen because of the land used to grow materials for bioplastics.

Even though bioplastics help reduce nonrenewable energy use and greenhouse gas emissions, they also cause environmental harm through land and water use, pesticide and fertilizer use, eutrophication, and acidification. Choosing between bioplastics and traditional plastics depends on which environmental impact is considered most important.

Some bioplastics are made from parts of crops that people can eat, like corn. These are called "1st generation feedstock bioplastics." They compete with food production because the same crops could be used to feed people. "2nd generation feedstock bioplastics" use non-food crops, like plants that are not eaten, or waste from food production, such as used cooking oil. "3rd generation feedstock bioplastics" use algae, which is not used for food.

Biodegradation is the process by which plastic breaks down. It happens at the boundary between solid plastic and liquid, where enzymes in the liquid break down the solid plastic. Some bioplastics and traditional plastics with special additives can biodegrade. Bioplastics can break down in different environments, such as soil, water, and compost, making them more acceptable than traditional plastics. The way bioplastics are structured and made affects how easily they break down. Environments like soil and compost are better for biodegradation because they have many types of microbes. Composting helps bioplastics break down quickly and reduces greenhouse gas emissions. Adding more sugar or increasing temperature in compost can improve biodegradation. Soil also helps bioplastics break down because of its many microbes, but it may take longer and need higher temperatures. Some bioplastics break down faster in water or oceans, but this can harm marine and freshwater ecosystems. Therefore, biodegradation of bioplastics in water can be a negative effect because it harms aquatic life and pollutes water.

Applications

Bioplastics have limited use in commercial settings. Cost and performance are still major challenges. For example, in Italy, a law passed in 2011 requires shoppers to use biodegradable plastic bags. These bioplastics are not only used for everyday items like packaging, plates, forks, bowls, and straws but also for specialized materials that can conduct electricity.

Biopolymers are sometimes used as coatings on paper instead of the more common coatings made from petroleum. Some bioplastics, called drop-in bioplastics, are chemically the same as traditional plastics made from fossil fuels but are produced from renewable resources. Examples include bio-PE, bio-PET, bio-propylene, bio-PP, and biobased nylons. These bioplastics are easy to use because existing equipment and systems can handle them. Other bioplastics, made through a dedicated bio-based process, can create products that traditional methods cannot produce, offering unique and improved properties compared to fossil-based alternatives.

The idea of bioplastics began in the early 1900s. Major progress happened in the 1980s and 1990s when scientists started creating biodegradable plastics from natural sources. The construction industry began paying attention to bioplastics in the late 2000s because of global efforts to build more environmentally friendly structures and the benefits bioplastics offer, such as better energy efficiency and the ability to break down naturally.

In recent years, bioplastics have improved in strength, cost, and performance. New mixtures of biopolymers and other materials have made bioplastics more suitable for construction uses, such as insulation and structural parts.

The future of bioplastics in construction appears promising. Continued research and innovation may expand their uses and improve their performance. As the construction industry focuses more on sustainability, bioplastics may become an important part of creating eco-friendly building materials.

Bioplastics provide a sustainable and flexible alternative to traditional construction materials, offering environmental and economic advantages. While challenges like cost and performance remain, improvements in bioplastic technology may 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 that only made bioplastics, called Marlborough Biopolymers, was created. However, Marlborough and other similar companies did not achieve lasting business success. The first company to achieve long-term financial success 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 save more carbon emissions than are needed to produce them. It is estimated that replacing 250 million tons of traditional plastic made each year with bioplastics would require 100 million hectares of land, which is about 7% of the world’s farmland. When bioplastics reach the end of their life cycle, those designed to be compostable or biodegradable are often thrown into landfills because there are not enough composting centers or proper waste sorting systems. In landfills, these materials break down without oxygen and release methane, a type of gas.

COPA (Committee of Agricultural Organisation in the European Union) and COGEGA (General Committee for the Agricultural Cooperation in the European Union) studied how bioplastics could be used in different parts of the European economy.

The bioplastics market is growing because more people want sustainable construction materials. This growth creates new economic opportunities for manufacturers and suppliers. The estimated size of the bioplastics market in 2024 is 7.41 billion USD, and it is expected to grow up to 127.55 billion USD by 2025. The European economy is expected to produce the largest share of bioplastics during this time.

History and development of bioplastics

• 1855: The first version of linoleum was created.
• 1862: At the Great London Exhibition, Alexander Parkes displayed Parkesine, the first thermoplastic. Parkesine is made from nitrocellulose and has good properties, but it is very flammable. (White 1998)
• 1897: Galalith, a bioplastic made from milk, was created by German chemists in 1897. It is still produced today and is commonly used in buttons. (Thielen 2014)
• 1907: Leo Baekeland invented Bakelite, which was 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 invented Cellophane using cellulose from wood, cotton, or hemp. (Thielen 2014)
• 1920s: Wallace Carothers discovered Polylactic Acid (PLA) plastic. PLA was very expensive to make and was not produced in large amounts until 1989. (Whiteclouds 2018)
• 1925: French microbiologist Maurice Lemoigne isolated and described Polyhydroxybutyrate.
• 1926: Maurice Lemoigne invented polyhydroxybutyrate (PHB), the first bioplastic made from bacteria. (Thielen 2014)
• 1930s: A car made from soybeans was created by Henry Ford. (Thielen 2014)
• 1940–1945: During World War II, plastic production increased because it was used in many wartime materials. Government support caused U.S. plastic production (including bioplastics) to triple between 1940 and 1945. (Rogers 2005) A 1942 U.S. government film called The Tree in a Test Tube showed how bioplastics helped the war effort and the economy.
• 1950s: Amylomaize, a type of corn with more than 50% amylose content, was bred successfully. This led to early research on commercial bioplastics. (Liu, Moult, Long 2009) However, development of bioplastics slowed because oil was cheap, while synthetic plastics continued to grow.
• 1970s: The environmental movement encouraged more research into bioplastics. (Rogers 2005)
• 1983: The first bioplastics company, Marlborough Biopolymers, was started. It used a bioplastic called biopal, which is made from bacteria. (Feder 1985)
• 1989: Dr. Patrick R. Gruber discovered how to make PLA from corn. This led to the creation of Novamount, a company that produces bioplastics for many uses. (Whiteclouds 2018)
• Late 1990s: BIOTEC developed TP starch and BIOPLAST, which led to the creation of BIOFLEX film. BIOFLEX film can be used in three ways:
• Blown films: sacks, bags, trash bags, mulch foils, hygiene products, diaper films, air bubble films, protective clothing, gloves, double rib bags, labels, and barrier ribbons.
• Flat films: trays, flower pots, freezer products, packaging, cups, and pharmaceutical packaging.
• Injection moulding: disposable cutlery, cans, containers, performed pieces, CD trays, cemetery items, golf tees, toys, and writing materials. (Lorcks 1998)
• 1992: A study in Science reported that the plant Arabidopsis thaliana can produce PHB. (Poirier, Dennis, Klomparens, Nawrath, Somerville 1992)
• 2001: Metabolix Inc. bought Monsanto’s biopol business (originally from Zeneca), which uses plants to make bioplastics. (Barber and Fisher 2001)
• 2001: Nick Tucker used elephant grass as a base to create plastic car parts. (Tucker 2001)
• 2005: Cargill and Dow Chemicals became NatureWorks, the leading producer of PLA. (Pennisi 2016)
• 2007: Metabolix Inc. tested a 100% biodegradable plastic called Mirel, made from corn sugar and bacteria. (Digregorio 2009)
• 2012: A bioplastic made from seaweed was developed. Research showed it is one of the most environmentally friendly bioplastics. (Rajendran, Puppala, Sneha, Angeeleena, Rajam 2012)
• 2013: A patent was filed for a bioplastic made from blood and crosslinking agents like sugars, proteins, and other chemicals. This bioplastic can be used for tissues, cartilage, tendons, ligaments, bones, and in stem cell delivery. (Campbell, Burgess, Weiss, Smith 2013)
• 2014: A study showed that bioplastics can be made by mixing vegetable waste (like parsley stems, cocoa husks, and rice hulls) with solutions of pure cellulose. (Bayer, Guzman-Puyol, Heredia-Guerrero, Ceseracciu, Pignatelli, Ruffilli, Cingolani, and Athanassiou 2014)
• 2016: An experiment showed that a car bumper meeting safety rules can

Testing procedures

To say a plastic product is compostable in Europe, it must meet the EN 13432 standard. This standard requires several tests and sets rules for passing or failing. For example, the product must break down physically and visually within 12 weeks, its polymeric ingredients must convert into carbon dioxide within 180 days, and it must not harm plants or contain harmful heavy metals. In the United States, the ASTM 6400 standard serves a similar purpose.

Many plastics made from starch, PLA, and certain co-polyester compounds like succinates and adipates have met these standards. However, plastics labeled as photodegradable or Oxo Biodegradable do not meet these rules in their current form.

The ASTM D 6002 method defined "compostable" as a plastic that breaks down as quickly as materials already known to compost under traditional rules. This definition was criticized because it ignored the traditional goal of composting, which is to create usable compost (humus) as the final product. In 2011, the ASTM removed this standard, which had allowed companies to legally label plastics as compostable. The ASTM has not yet replaced this standard.

The ASTM D6866 method measures the amount of carbon from living organisms in bioplastics. Carbon-14, a radioactive form of carbon, is found in the atmosphere and absorbed by plants during photosynthesis. Over time, carbon-14 decays, leaving only carbon-12 in fossil fuels. Biomass products contain carbon-14, while petrochemical products do not. Scientists use an accelerator mass spectrometer to measure the percentage of renewable carbon in a material.

Biodegradability and biobased content are different. A bioplastic like high-density polyethylene (HDPE) can be 100% biobased (made from renewable carbon) but still not biodegrade. These plastics help reduce greenhouse gases when burned for energy because their carbon is considered carbon-neutral, as it originally came from biomass.

Testing methods like ASTM D5511-12 and ASTM D5526-12 follow international standards, such as ISO DIS 15985, to assess the biodegradability of plastics.