Due to the overuse of humans, there are now about 8 billion tons of plastic waste piled up on the surface and in the ocean. It is no wonder that plastics have been in poor reputation in recent years.
But the importance of plastic is also unquestionable. The invention of plastic revolutionized life in the 20th century. It is durable, versatile, and hygienic. Such materials are almost non-existent in nature. If there is no plastic, we will never create records, tapes, film, etc. Naturally, we will not be able to record music, film, or develop modern medicine. Auto parts, light aircraft materials, satellites and spacecraft also rely on plastics, and global travel and space exploration are possible, not to mention computers, mobile phones and a wide range of networking technologies. Look around, if there is no plastic, our life will be difficult.
Despite the importance of plastics, the disposal of plastics has always been a tricky issue. Not only that, but the source of plastic is also a headache. Plastics are made from fossil fuels, and about 40% of the oil and natural gas consumed by humans every year is used to produce plastic polymers. It may not sound like much, but it still involves issues of fossil fuel extraction and climate change.
Bioplastics - does it sound so good?
So, do we have alternatives? Bioplastics such as polylactic acid (PLA) are now a development area that many people are focusing on, such as disposable tableware made of potatoes, plastic bottles made of corn, garbage bags made from food residues, etc., although it sounds like It's like an ideal solution, but the truth is far from that simple. First of all, bioplastics do not sound so easy to degrade and generally require industrial processing. Not only that, but also the production of bio-plastics requires a lot of energy. The steps of harvesting crops and processing raw materials emit more carbon dioxide than traditional plastics.
Foreign researchers have recently examined the environmental impact of the production of plastic bottles from various materials, including the use of corn and recyclable polyester, etc., and found that the performance of bioplastics is not satisfactory.
Considering the cost of fertilizers, transportation and harvesting costs, the benefits of plastics made from biomaterials are the worst, and the best performers are plastics produced from crude oil. The researchers said that this is not what they hope to see.
The water and fertilizers used to produce bioplastics can also pollute rivers and estuaries, leading to eutrophication of water bodies. In addition, if people inadvertently throw biowaste into recyclable waste, they will pollute the entire recycling chain. Reduce the quality of recycled plastics.
So from the current point of view, the performance of bioplastics is still quite disappointing.
In addition to bioplastics, there is another alternative: making plastics from carbon dioxide. Scientists have been working in this field for more than a decade, and now they finally see the dawn of hope.
Making plastic from carbon dioxide
Scientists point out that instead of using fossil fuels as raw materials for plastics, we are better off doing the opposite. Using some chemical techniques to make plastics from waste carbon dioxide, this will revolutionize the entire petrochemical industry. Most of the current carbon dioxide comes from hydrogen production, but researchers are still trying to capture carbon dioxide from industrial waste. This approach will not only reduce the use of fossil fuels, but also affect climate change and reduce greenhouse gas emissions.
The key to producing plastics from carbon dioxide is the design of the catalyst, such as compounds containing metals such as copper. Scientists have discovered that there is a catalyst that allows carbon dioxide and epoxide to react to form a class of substances called polyether polycarbonate polyols, which are the basis for the production of polyurethanes, which are often used to make beds. Pads, cushions and insulation for the refrigerator.
One day, we may be able to use "air" to produce plastic. One day, we may be able to use "air" to produce plastic.
Making a mattress with gas
A German company is producing a special mattress called Cardyon, 20% of which is made of carbon dioxide. Considering that the current annual production of polyurethane in the world exceeds 15 million tons, if the raw materials are replaced by carbon dioxide, it will inevitably have a huge impact.
British company Econic is also producing polyurethane with carbon dioxide, hoping to launch foam, paint, sealant and elastic fiber within two years. The quality of these materials is not only comparable to traditional plastics, but in some respects even better than traditional plastics. Econic points out that some of the materials they produce are more excellent, such as fire resistance, scratch resistance and more.
According to the company's estimates, if 30% of the polyol is made of carbon dioxide, it can reduce 90 million tons of carbon dioxide emissions, equivalent to a variety of 4 million trees, or a reduction of 2 million cars. In addition, due to the low price of carbon dioxide (about $100 per ton, compared to the standard raw material propylene oxide of about $2,000 per ton), a factory that produces 50 metric tons per year can save 1,000 per year. Ten thousand U.S. dollars.
Scientists even have a bigger "ambition": the production of ethylene from carbon dioxide. About half of the plastics produced worldwide are made of ethylene, so ethylene is one of the most important industrial raw materials in the world. Researchers are working on a copper-containing catalyst that produces carbon dioxide and water to produce ethylene under energization.
It may take another 20 years for polyethylene plastics made from carbon dioxide to be commercialized, but in the next 30 or 40 years, we can no longer use fossil fuels to produce ethylene, so we have no choice. Other methods must be sought.
British scientists have invented a method that combines carbon dioxide with sugars such as xylose to form polycarbonate (which can be used to produce recyclable containers such as baby bottles). In the current polycarbonate production process, phosgene (a highly toxic gas used as a chemical weapon in World War I) and a chemical called bisphenol A are generally used. Bisphenol A has an estrogen-like nature and has been banned for use in infant products by countries such as Canada. If polycarbonate is produced on the basis of carbohydrates, the safety of its production and use will be greatly enhanced, making it more suitable for the production of medical implants, sutures and organ scaffolds.
American scientists have also invented a new technology that uses an electrocatalyst containing nickel and phosphorus to combine water and carbon dioxide under the action of electricity to produce complex carbon-containing molecules that can be used to produce products such as plastics and pharmaceuticals. Researchers say the essence of this process is equivalent to artificial photosynthesis and can be more efficient than natural photosynthesis.
Traditional plastic production methods may be the current normal, but not ideal. The use of fossil fuels to produce monomolecular substances consumes both energy and environmental pollution. Because thermal energy drives chemical reactions at a slow rate, consumes a lot of energy, and is inefficient, we must find another way to find a better solution.
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