Plastic gives us a lightweight, strong and inexpensive material to use, but it has also caused the plastic apocalypse and huge environmental risk. Different kinds of plastic take anywhere between 400 and 1,000 years to degrade in a landfill. About 91% of it isn’t recycled. This means that most of the more than 6.3 billion metric tons of plastic products that have ended up as trash is still around. So much plastic is thrown away every year that it’s enough to circle the Earth four times.
We are not only hurting the environment by using so much plastic, we are damaging our own bodies and sea life. Every year, millions of tons of unrecycled plastic pollutes our oceans resulting in potentially major damage to marine life, biodiversity, food security, and human health. Broken down by waves, sunlight and marine animals, a single plastic bag can become 1.75 million microplastic fragments. Those microplastics might finally end up in our bodies through the fish we eat or the water we drink. Chemicals in plastics interact with hormones and may lead to numerous health problems, including heart disease and diabetes. Plastic fragments from bags, bottles and other items that are laced with chemicals can be ingested by marine animals and poison them.
The problem of plastic waste is one of the greatest challenges faced by the current generation. The development of renewable, sustainable, and biodegradable alternatives for plastic materials is therefore essential.
The limitations of traditional plastic recycling are numerous. First, not all plastics are recyclable, and even those that are recyclable cannot be recycled infinitely. Additionally, the recycling process can be energy-intensive and often involves the use of chemicals and other materials that can be harmful to the environment. Furthermore, many plastic products are used only once before being discarded, which means that even if they are recyclable, they may not be collected and processed properly.
For in-depth understanding on Ocean Cleaning technology please visit: Cleaning Up Our Oceans: The Technology Behind Tackling Plastic Pollution
These limitations have led to the need for sustainable alternatives to traditional plastics. Bioplastics are one such alternative that has gained popularity in recent years. Bioplastics are made from renewable materials such as cornstarch, sugarcane, and vegetable fats and oils. They can be biodegradable or compostable, meaning they can break down naturally in the environment without causing harm.
Bioplastics are a type of plastic material derived from renewable sources, such as plants or microorganisms, as opposed to traditional plastics that are made from non-renewable sources like fossil fuels. Bioplastics can be classified into two main categories: biodegradable and non-biodegradable.
Biodegradable bioplastics are capable of being broken down by microorganisms into natural substances like water and carbon dioxide, making them a more sustainable alternative to traditional plastics. Non-biodegradable bioplastics, on the other hand, are made from renewable sources but do not biodegrade and can still have a negative impact on the environment if not properly disposed of. Examples of bioplastics include polylactic acid (PLA), polyhydroxyalkanoates (PHAs), and starch-based plastics.
In recent years, nanomaterials have displayed potential in effective detection and removal of greenhouse gases, chemical contaminants, organic pollutants, and biological agents. These materials come in various morphologies and have various functions (e.g., adsorbents, catalysts, or membranes). The high reactivity and high surface area of nanomaterials are some of the notable features which provide an advantage in environmental remediation over other conventional alternatives.
Given the abundance of plant resources, plant extracts are the most studied category to date for the synthesis of green nanomaterials. Cellulose is one of the most abundant and pervasive bioipolymers on earth. Cellulose based raw materials have been traditionally used in many fields, because of their unique advantages including renewability, biocompaitiblity, low cost, natural biodegradability and chemical stability. It has been used as an engineering material for thousands of years and continues to be used today in forest products such as paper, textiles, etc. Novel cellulose based functional materials, such as cellulose hydrogel, aerogel and porous materials have been developed in various fields.
In 2019, Estonia, researchers at Tallinn University of Technology (TalTech) have developed a biodegradable packaging material from cellulose. Andres Krumme, a professor in TalTech’s Department of Materials and Environmental Technology, has developed cellulose-based plastic that can be melted and processed in the same way as low-density polyethylene. “Cellulose biopolymer is generally highly crystallized with strong hydrogen bonds, which means it can’t easily be melted or processed,” Krumme adds. “But our new polymers—cellulose fatty acid esters—can be processed in the same way as the commodity polymers.” Krumme also notes that cellulose is extremely abundant and using less than 1% of the planet’s resources could replace all petroleum-based plastics currently produced. Taltech is working to pilot the production process.
For in-depth understanding on Bioplastics technology and applications please visit: Bioplastics: A Sustainable Alternative to Traditional Plastics.
Biodegradable plastics have been advertised as one solution to the plastic pollution problem bedeviling the world, but today’s “compostable” plastic bags, utensils and cup lids don’t break down during typical composting and contaminate other recyclable plastics, creating headaches for recyclers. Most compostable plastics, made primarily of the polyester known as polylactic acid, or PLA, end up in landfills and last as long as forever plastics.
University of California, Berkeley, scientists have now invented a way to make these compostable plastics break down more easily, with just heat and water, within a few weeks, solving a problem that has flummoxed the plastics industry and environmentalists, reported in April 2022.
According to Japan’s Osaka University, various groups have already developed plastics that harmlessly biodegrade in the ocean environment. However, these have three main drawbacks: they’re of inferior quality to conventional plastics, they cost over twice as much to produce, and they can only be manufactured in relatively small amounts. Led by Assoc. Prof. Taka-Aki Asoh and Prof. Hiroshi Uyama, an Osaka team therefore developed an alternative type of transparent plastic consisting mainly of cellulose nanofibers and starch, both of which were obtained from plants.
Thanks to a proprietary production process, the finished product is claimed to exhibit excellent water-resistance and high strength, while also being very biodegradable when left floating in seawater over time. And as an added bonus, because the plastic isn’t petroleum-based, its production shouldn’t produce any greenhouse gases. “Since we were able to develop a marine biodegradable plastic sheet by combining familiar materials such as starch and cellulose, because these materials are cheap, and the manufacturing process is simple, we can expect that the developed material will be put to practical use soon,” says Asoh. “We have great expectations that our material will help solve the growing global problem of marine debris accumulation and have a major societal impact.”
Researchers from the Institute of Oceanology under the Chinese Academy of Sciences have found a marine fungus species that can efficiently degrade polyethylene and other plastics, with some plastics degraded into pieces in merely two weeks, reported in April 2022.
It has been confirmed that the fungus can exhibit a degradation efficiency of about 95 percent and is harmless to the environment, Sun said. The researchers have improved the culture condition and degradation efficiency of the fungus. Polyester polyurethane and biodegradable plastics can be degraded to fragments within two weeks by the fungus.
The new technology should theoretically be applicable to other types of polyester plastics, perhaps allowing the creation of compostable plastic containers, which currently are made of polyethylene, a type of polyolefin that does not degrade. Xu thinks that polyolefin plastics are best turned into higher value products, not compost, and is working on ways to transform recycled polyolefin plastics for reuse.
Biodegrading 3D printing material invented in Navy lab
A team of scientists at the Naval Surface Warfare Center in Panama City, Florida, was issued a 20-year patent for a 3D printable material made of a marine-biodegradable base polymer that it says is easy to build from and would break down over time. The use of unmanned or autonomous underwater vehicles (UUVs) to house and deploy oceanic sensors may be made to be single-use (disposable) or to last a certain amount of time before ceasing to function. Retrieval from the ocean floor can be costly or impossible, so in some cases they may be abandoned—a less than an eco-friendly solution.
But the new material, invented by Josh Kogot, Ryan Kincer, and April Hirsch in the center’s Biotechnology Research and Development Lab, and buoyed by the patent issued Tuesday, offers a unique solution. By tweaking a combination of polymers including polycaprolactone (PCL), polyhydroxyalkanoate (PHA), or polybutylene succinate (PBS), along with an agar gelling agent, the material can be 3D printed into any size or shape and made to last a specific amount of time before degrading. “There is currently no known way to design and produce these structures so that their rate of degradation can be controlled,” the patent reads. “There is an unmet need to produce marine biodegradable 3D printable structures for which the rate of degradation of each structure can be selected for a particular mission.”
By incorporating biological materials, like the synthetic hagfish slime the same lab invented, the process of biodegradation of the carrier vehicle structure is accomplished by microorganisms or enzymes feed on the biodegradable polymers that comprise the structure. Through technology transfer, the new biodegradable 3D printing material technology is available to private companies via license agreement. TechLink, the Department of Defense’s national partnership intermediary for technology transfer is providing licensing services to businesses at no cost. Brian Metzger, a senior technology manager at TechLink, works with the Navy tech transfer team in Panama City to help private companies commercialize their growing list of inventions. Metzger said that the new printing material could be used for any number of applications, not just UUVs and that the first step to commercializing it is licensing the patent.
“Not only can you 3D print this material into just about anything, but to finely control the rate at which it degrades is really useful,” Metzger said. “This technology has the potential to cut costs and benefit the environment, it could have many military and commercial applications for all types of underwater equipment.”
Scientists Develop Cellulose-Based Plastic Substitute
Researchers at the University of Science and Technology of China have used cellulose, the most abundant organic molecule on Earth, to develop a strong and light plastic substitute. Their findings have been published in Science Advances.
To develop an alternative to plastics, a team led by Professor Yu Shu-Hong has turned to cellulose, the main material in the cell walls of plants. Cellulose nanofibers, which can be derived from plants or bacteria, are stronger than steel and more heat resistant than silica glass, making them in ideal nanoscale building block for constructing high-performance materials, Yu said.
Using the bacteria Gluconacetobacter xylinus, the team first produced cellulose hydrogels that they cut into sheets. After treatment, the sheets were stacked, pressed together and heated until they were completely dry, resulting in cellulose nanofiber plates. These cellulose nanofiber plates were four times stronger than steel and tougher than aluminum alloy, despite being only half its density. Unlike plastics or other polymer-based materials, the cellulose nanofiber plates were extremely heat resistant, with a thermal expansion coefficient similar to that of ceramic materials. Furthermore, the plates retained their strength despite undergoing ten rapid thermal shocks where they were baked at 120°C and then immersed in -196°C liquid nitrogen.
The researchers reported that the plates could be produced for as little as US$0.50/kg, making them cheaper than—and thus likely to displace—most plastics. In particular, they suggested that the low density, toughness and thermal stability of the cellulose nanofiber plates makes it an attractive and environment
Cellulose Nanopaper as Plastic Substitute
Nanopaper has attracted attention as a low-cost, environmentally friendly, high-performance material with strong potential to replace plastic substrates in many electronic and material applications.
Paper-based materials like nanopaper are excellent substrates for functionalization by nanoparticles (NPs) because the porous structure allows for high NP loadings. Additionally, paper-based materials can be effectively functionalized by a wide variety of NPs, resulting in materials suitable for a wide range of applications. For example, the use of inorganic NPs (e.g., TiO2, Au, Ag) can produce paper-based materials with excellent catalytic, antibacterial, sensing, and anticounterfeit properties.
Netherlands Researchers have developed transparent UV-blocking nanopaper by embedding tunable UV-absorbing NPs from ethyl cellulose into nanopaper. These functional nanopaper films are highly transparent, selectively block UV light, and show excellent photostability, therefore with great potential as high-performance, renewable, sustainable, and biodegradable materials for photoprotection applications.
Chinese scientists develop robot fish that gobble up microplastics
A team of Chinese scientists from Sichuan University in southwest China has envisioned robot fish that “eat” microplastics which may one day help clean up the world’s polluted oceans. Soft to touch and just 1.3 centimeters (0.5 inch) in size, these robots already suck up microplastics in shallow water. The team aims to enable them to collect microplastics in deeper water and provide information to analyze marine pollution in real time, said Wang Yuyan, one of the researchers who developed the robot.
“We developed such a lightweight miniaturized robot. It can be used in many ways, for example in biomedical or hazardous operations, such a small robot that can be localized to a part of your body to help you eliminate some disease.” The black robot fish is irradiated by light, helping it to flap its fins and wiggle its body. Scientists can control the fish using light to avoid it crashing into other fish or ships. If it is accidentally eaten by other fish, it can be digested without harm as it is made from polyurethane, which is also biocompatible, Wang said.
The fish is able to absorb pollutants and recover itself even when it is damaged. It can swim up to 2.76 body lengths per second, faster than most artificial soft robots. “We are mostly working on collection (of microplastics). It is like a sampling robot and it can be used repeatedly,” she said.
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