By Liu Rencai, University of Chinese Academy of Sciences
With the enhancement of the environmental protection awareness, the whole plastics industry is facing the challenge of transforming from non-degradable plastics to biodegradable polymer plastics. The performance and processing technology of biodegradable polymers have been greatly improved and can thus replace some traditional plastics. It is predicted that in the near future, biodegradable polymer plastics will completely substitute non-decomposable plastics.
Promotion of new materials needs policy support
The governance of white pollution has become one of the top priorities of governments around the world. Countries have introduced many rules and regulations on the restriction of plastics. The Chinese government passed the draft of Renewable Energy Regulations and Solid Waste Regulations in 2004 to encourage the promotion and application of biodegradable plastics; established a special fund for the promotion of biodegradable materials development in 2006; issued definitions, classifications and labeling of degradable plastics and regulations on their degradable performance in 2007. In 2008, the State Council issued a notice to restrict the production and sale of plastic shopping bags and implemented a system of paid use of plastic bags. With the support of various domestic and foreign policies, biodegradable plastics can be expected to enter the golden age of development.
Market demand is growing rapidly
The demand for biodegradable polymer materials has increased significantly since 2014. It is estimated that the global biodegradable polymer demand will be reaching 360 kt in 2018, and the annual growth rate will reach 9% in the next five years. It is expected that the global biodegradable polymers consumption will increase by more than 50% by 2023, totaling 550 kt. According to the IHS Markit analysis, the global biodegradable polymer market has exceeded US$1.1 billion in 2018, and the global market share is expected to reach US$1.7 billion by 2023. Europe's growth in the demand for biodegradable polymer is especially obvious due to the introduction of favorable policies on the promotion of biodegradable plastics in Europe. It is expected that Asia-Pacific market will witness more competition and biodegradable polymer plastics’ market shares will increase from 26% in 2013 to 33% in 2019.
The major application sectors of biodegradable polymer plastics are packaging, fiber textile, agriculture and plastics industries, of which the packaging industry accounts for 70% of the total. The one-off packaging industry will become the mainstream benefiting from the “plastics restriction order” or “plastics prohibition order”, and disposable tableware such as cups, plates, cutlery and plastic shopping bags will have a large room of growth. In addition, biodegradable plastic water bottles may immerge as a new consumer as the biodegradable polymer materials. The plastarch material can also be made into sheets and plates with mechanical shock resistance and shock absorption properties, which can be comparable to that of conventional polyurethane foam materials. Meanwhile, as the global aging social structure is gradually formed, the medical needs for biodegradable polymers in the future may become one of the main growth factors.
Development dilemma of biodegradable difficulties
The followings are the major development difficulties of biodegradable polymer plastics: 1) The technology is not mature, and the performance of degradable plastics cannot fully replace the traditional plastics yet. At present, the comprehensive performance of biodegradable polymer plastics cannot compete with that of the petroleum-based products. For example, there is still a huge gap between biodegradable polymer plastic tableware and the traditional disposable plastic tableware in terms of mechanical strength, heat resistance and waterproofness. 2) The evaluation system for degradable plastics standards in various countries are still not perfect. Up to now, the evaluation systems for biodegradable polymer plastics have not been unified in various countries. 3) The cost remains high. The cost of biodegradable polymer plastics is still higher than that of traditional plastics in terms of feedstock and production, which hinders their application.
Development direction of biodegradable polymers
Followings are three major development directions of biodegradable polymers:
The first development direction is compost, which can be applied to remove the domestic garbage. The market potential of degradable polymer plastic compost is worthy of attention. According to statistics, in 2014, 53% of the US waste was buried, 26% was recycled, 13% was burned, and only 9% was dealt with composting. The biodegradable polymer plastic which is completely degraded by compost is expected to be used in the removal of domestic garbage and is beneficial to organic agriculture.
Secondly, with the advent of the aging society, due to the biocompatibility of most biodegradable polymers, they may enter the field of medical materials, which will be one of the most promising applications of biodegradable polymers in the future. Taking polylactic acid (PLA) for example. In recent years, this material has begun to enter the field of biomedical materials as bone nails, bone plates, surgical sutures, drug carriers and tissue engineering materials, replacing the traditional metal medical implants. Besides, polyester lactone (PCL), water-soluble polyvinyl alcohol (PVA) and polyhydroxyalkanoate (PHA) are also biomedical degradable polymers that will be developed in the future and generate considerable profits.
Last but not least, composite biodegradable polymers are also one of the key development directions. Since a single degradable polymer does not have many excellent properties, composites consisting of two or more degradable polymers enjoy better mechanical properties, shorter degradation rates, improved processing performance and reduced costs. Such composites help to promote the applications of degradable polymer materials.
