In the 19th century, hayatt, an American printer, saw a reward for finding a substitute for ivory. After repeated experiments, he found that the material obtained by adding camphor to nitrocellulose was hard but not brittle, and could be shaped into various shapes at will. He named the material "Celluloid nitrate," the first synthetic plastic in human history. In 1907, American chemist Baekeland realized the synthesis of phenolic resin, which opened the prelude to the application of synthetic polymer plastics. The word plastic comes from the Greek word "plastikos", meaning a substance shaped into any shape.

In the past half century, the production of plastics has increased more than 20 times. They are light, durable, low-cost and versatile. They have become a ubiquitous product. Plastic footprints are found in every corner of the world, including the deepest sea floor, the summit of Mount Everest and the polar ice sheet.

Plastic is harmful to the environment because it is difficult to degrade. Is it possible to change the material formula to make it eventually degrade under specific environmental conditions? Biodegradable plastics are highly sought after and expected. But can biodegradable plastics cure plastic pollution?

Xu Zhonghua, vice president of R & D Asia of France's total group and chief scientific representative of total China, believes that it is unrealistic to promote large-scale biodegradable plastics based on bio base. 'for quite a long time, we still have to rely on traditional plastic products,' he said in an interview with surging news.

"The premise of popularizing the use of bio based plastics is to give priority to the protection of food security. In addition to the problem of where the raw materials come from, the cost of biodegradable plastics is still higher than that of ordinary plastics. At the same time, we should strengthen the recycling of traditional plastics, give full play to their value, and gradually move towards an environment-friendly sustainable development road Xu Zhonghua said.

Biodegradable plastics, the terminator of plastic pollution?

Where does plastic waste come from? Straw and packing bag of online ordering, tape and buffer in express box, and solid plastic particles in shower gel are produced in large quantities all the time. The global spread of COVID-19 has created a sudden increase in plastic demand, disposable masks, protective clothing, gloves, and the packaging of the best selling disinfectant products. Plastic shapes are everywhere.

The vast majority of fossil based plastics can not be degraded, which means that they may exist in nature for hundreds or even thousands of years. Since the 1980s, scientists began to study whether plastics can be degraded and disappeared in the environment with active microorganisms. Polylactic acid (PLA) products from corn and other crops are the most successful biodegradable plastics. PLA is completely recyclable and biodegradable because it is an all bio based material. It can be recovered by mechanical or chemical means or, in some cases, used as fertilizer by composting.

In addition to being a well-known multinational oil and gas giant, total has long entered the field of biodegradable bio based materials and biofuels. In 2007, total and galactic set up a joint venture company futero in Belgium to explore the production of PLA bioplastics from renewable plant resources. In 2018, the PLA plant jointly built by total and its Dutch partner corbion was put into operation in Thailand to produce bio based polymers from non transgenic sugarcane. With an annual capacity of 75000 tons, the plant is the second largest PLA plant in the world.

Total Thailand PLA plant uses non transgenic sugarcane as raw material to produce bio based polymers

Xu Zhonghua said that there are several development directions for Degradable Plastics: in addition to PLA, which can be completely decomposed into carbon dioxide and water under specific conditions, there are also destructive biodegradable plastics that can promote degradation through additives, and photodegradable plastics that add light sensitive photoinitiators and other additives to the polymer chain of traditional plastics.

With the rise of the global plastic reduction movement, the emergence of "biodegradable plastics" in the market has been mistakenly regarded as "Saviour" by many people. People seem to feel at ease when they discard this kind of plastics, because they assume that these plastics will eventually degrade in the environment and will not cause harm. However, it is worth noting that degradable plastics also need to be recycled and properly disposed of in a specific way, and should not be discarded at will.

One of the reasons why the plastic dilemma is difficult to solve is that people's requirements for materials are changing in the whole life cycle of a plastic product“ In the process of use, the strength, temperature resistance and moisture resistance of plastics should meet certain conditions. Even degradable plastics can only be decomposed under the combined action of specific temperature, humidity and microorganisms after being discarded. They will not "disappear" in the natural environment, otherwise they will not be able to realize the use function at room temperature. "

Biodegradable plastics are not everything. Xu Zhonghua said that at the beginning of the establishment of total's Belgian PLA plant, there were many difficulties in product promotion. Even now, the whole degradable plastics industry is still facing a series of common challenges. For example, the cost is higher than that of ordinary plastics, and the application range of bio based materials is narrowed.

But the greater restriction is that we can't compete with grain for resources“ The biggest challenge, whether it is to make plastics or lubricants with biological materials, is where the raw materials come from. First of all, we can't compete with traditional food crops for land resources. Under this basic premise, Thailand is a very good choice for us to be as close as possible to the place where we can provide raw materials with a certain scale, low cost and long-term guarantee. " At present, PLA plant of total Thailand has launched PLA materials for different industries, which are used in food packaging, automobile interior decoration and so on. In general, PLA materials are more suitable for areas with higher requirements for food safety, such as tea bags, capsule coffee and so on.

Total's PLA plant in Belgium

Based on the above reasons, Xu Zhonghua believes that there is still a development process for large-scale application of bio based degradable plastics. If all the biodegradable plastics are used in the world today, it will have a great impact on the food supply.

"At the present stage, it is more suitable for specific fields related to food and medical treatment. Maybe in the future we can develop carbon dioxide based plastics, which will eventually decompose into gases. But there is still a long way to go before we can make further breakthroughs in technology and completely rely on degradable plastics. "

Plastic recycling under the ban is not only a matter for manufacturers

China is the world's largest producer and consumer of plastics. In 2019, China will produce 63 million tons of waste plastics and recover 18.9 million tons. In recent years, China's plastic pollution control system has been continuously upgraded from the "foreign waste" ban to the new "plastic restriction order".

In 2007, the Chinese government issued the "plastic restriction order" for the first time. The core is to ban the production, sale and use of ultra-thin plastic shopping bags nationwide from June of the next year, and implement the system of paid use of plastic shopping bags. The plastic restriction order has been implemented for more than ten years, and its effect is controversial. However, it is undeniable that with the rapid rise of e-commerce, express delivery and takeout industries, disposable plastic packaging materials have switched to the main battlefield, and the consumption has increased instead of decreasing.

In 2019, an average of 7.08 million pieces of express will be sent to the whole country every hour. According to the statistics of environmental protection agencies, the total length of adhesive tape consumed by domestic express industry in 2018 exceeded 39.8 billion meters. These plastic tapes can wrap around the earth nearly 1000 times, compared with 425 in 2015. 99% of the waste plastic will be mixed with domestic waste and eventually burned or buried.

At the beginning of this year, the national development and Reform Commission (NDRC) and the Ministry of ecological environment jointly issued the updated "plastic restriction order", which formulated a clear timetable and put the policy measures of plastic reduction and recycling through the whole process and links of plastic products production, circulation, use, recycling and disposal.

"Plastics are human friends, not enemies. They provide a lot of support and convenience for the development and progress of human society." Xu Zhonghua said that under the plastic restriction order, it is most important for everyone to participate in the efficient recycling of plastics. The treatment of waste plastics is not only the business of producers and scientists, but also the business of plastic users. The challenge of plastic recycling can be greatly reduced if the public do a good job in waste classification.

In February 2019, total acquired French plastics recycling company synova. Combine polymer expertise with synova's recycling expertise to increase the supply of recycled polypropylene for automotive applications. Synova can produce 20000 tons of polypropylene from recycled plastics every year.