Bioplastic
Bioplastics are materials derived from renewable biological resources, such as plants and microorganisms, offering an alternative to conventional plastics made from fossil fuels. These eco-friendly substances can be molded into various shapes and are designed to decompose more readily than traditional plastics, especially under suitable environmental conditions. Common applications of bioplastics include disposable food packaging, straws, and medical devices, reflecting their versatility. Historical development traces back to the mid-19th century with the creation of Parkesine, the first synthetic bioplastic, and has evolved significantly over the years, especially in response to growing environmental concerns since the 1980s.
Types of bioplastics include those based on plant starch, cellulose, and bacterial fermentation products like polyhydroxyalkanoates (PHA). While bioplastics generally present environmental benefits, such as a reduced carbon footprint and lower pollution potential, they are not without challenges. Many require specific conditions for biodegradation, and the production cost can be higher than that of traditional plastics. Additionally, concerns exist regarding their behavior in landfills and the potential release of harmful by-products. As research continues to innovate in this field, bioplastics are increasingly viewed as a promising solution to combat plastic pollution and promote sustainability.
Bioplastic
Bioplastics are nature-based substances that are soft enough to be formed or molded but become hard enough to hold their shape. Unlike conventional plastics, which are derived from nonrenewable fossil fuels like petroleum, bioplastics are made from fats, oils, starches, or microbial life-forms obtained from renewable sources such as corn, soybeans, seaweed, egg whites, and shrimp shells. Petroleum-based plastics decompose so slowly that they are generally considered nonbiodegradable, but most bioplastics will disintegrate relatively quickly under the right conditions.
Bioplastics are commonly used to make items such as disposable food packaging, egg cartons, water bottles, and straws. They can also be used to make grocery store bags, plastic pipes, carpeting, mobile phone cases, and even some medical implant devices.
History
British inventor Alexander Parkes developed the earliest known synthetic bioplastic in 1856. His polymer, Parkesine, was made from a material that came from cellulose. He showed off his discovery at the 1862 Great International Exhibition in London, England. Experimentation with bioplastics continued into the 1900s. American automobile pioneer Henry Ford made car parts out of bioplastics for his Model-T, and he manufactured a car with body parts constructed from soy-based plastics in 1941. In 1926, French chemist Maurice Lemoigne discovered that Bacillus megaterium, a type of bacterium, produced a form of non-synthetic plastic known as polyhydroxybutyrate (PHB).
Over the next several decades, researchers attempted to identify cheaper, renewable raw materials to keep up with the growing demand for plastic products, but most plastics were still made from petroleum-based polymers. That began to change in the 1980s as concerns about the pollution generated by nonbiodegradable plastics increased, and more scientists began to look into bioplastics.
Types of Bioplastics
There are several types of bioplastics. The most common bioplastics made in the twenty-first century are plant-starch based. Celluloids are a common form of bioplastics made from plant cellulose, much like the material used by Parkes in the 1860s. PHB, the bacteria-produced plastic identified by Lemoigne, is growing in popularity as well. Polylactic acid (PLA) is another common bioplastic produced from corn sugar.
Polyhydroxyalkanoates (PHA) are a form of bioplastic generated by a bacterial fermentation process, much like PHB. For mass production, the microbes are provided within an environment that encourages the production of PHA, which is then harvested and processed. The petroleum-based plastic polyethylene can also be made as a bioplastic using ethylene generated from natural sources like sugarcane.
Benefits
Bioplastics provide some environmental benefits over petroleum-based polymers. Most bioplastics break down quickly with the help of natural microorganisms. This could help alleviate some of the problems caused by discarding large amounts of plastic products, which include water pollution and overstuffed landfills. Plastic store bags and food packages that dissolve when exposed to the elements can also help curtail unsightly litter. This protects the natural environment as well as the health of the animals that live in it.
The use of bioplastics decreases the need for fossil fuels to produce plastic items. The renewable nature of the materials used to make bioplastics offers another advantage over plastics produced from nonrenewable fossil fuels. Also, the process used to make bioplastics generally has a lower carbon footprint than the process used to make traditional plastics.
Additionally, bioplastics are often softer than synthetic plastics, with a feel that may be more appealing to consumers. They are easier to print on, they are less likely to alter the flavor of any food they contain, and they are more transparent than plastics made from petroleum. Some also allow water vapor to pass through more easily, which can be an advantage in some applications, such as wrapping fresh bakery items. Researchers are also developing specialized bioplastics. One example is a bioplastic made from egg whites that has antibacterial properties and could have many applications in the medical and food industries.
Bioplastics are also free of bisphenol A (BPA), a chemical that many believe has a detrimental effect on human health when used in plastics that store food. In 2024, researchers at Virginia Tech's College of Agriculture and Life Sciences announced that they were in the process of developing biodegradable bioplastics that could be created from food waste. They theorized that such a material could result in significant reductions in plastic pollution. Unlike previous projects promising similar goals, this project utilized a much more affordable manufacturing process.
Concerns
Most, but not all, bioplastics are biodegradable. Some, while technically considered biodegradable, require a specific set of circumstances for decomposition to occur. In order to decompose, most bioplastics need an environment with moisture and oxygen, such as a compost pile. A bioplastic item placed in an airtight landfill will become as nonbiodegradable as its petroleum-based counterpart. This is also a concern for products that are made of multiple types of plastic, such as ink pens, which might have a biodegradable casing but contain a traditional plastic tube that holds the ink.
Some researchers are also raising concerns about by-products from the biodegradation process that are showing up in water and soil. One problem is the amount of methane—a greenhouse gas that raises the temperature of the atmosphere—produced when bioplastics are placed in landfills.
Another issue is the cost of producing bioplastics. Compared to traditional plastics, the bioplastic PLA costs about 20 percent more to produce. PHA, which is slightly more biodegradable than PLA, costs twice as much to produce as a petroleum-based plastic.
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