Green Plastic Ideas and Practice Analysis (1)

In recent years, a new field has emerged in the research of international new materials, namely ecological environmental materials. Eco-environmental materials refer to materials that consume as little resources and energy as possible, have little impact on the eco-environment, are highly recycled, and are degradable or reusable. Eco-environmental materials include: environmental engineering materials, green packaging materials, environmental building materials, environmental degradation materials, environmental purification materials, environmental remediation materials, and environmental substitute materials.

Green materials are another reference for ecological environmental materials. The concept of green materials was first proposed in 1988 at the First International Conference on Materials Science. In 1982, the international academic community defined green materials as the materials that have the least environmental burden on the earth and are not harmful to human health in such links as raw material adoption, product manufacturing, application processes, and recycling after use. The plastic that meets the above definition of green material is called green plastic. The principle of consensus on green plastics is that the connotation of green plastics should include five aspects: it does not affect human health, energy efficiency, resource efficiency, environmental friendliness, and high endurance.

In recent years, as environmental issues, energy issues, and personal health and safety issues are valued, green plastics are increasingly showing strong growth momentum.

Pay attention to and develop green plastic

Environmental protection needs

As a major invention of the 20th century, synthetic plastics, because of its durability, have made it widely used in many fields of application. However, this performance has caused it to exist in the environment for a long time, coupled with its light weight (large volume), large combustion heat value and other reasons, has become a difficult problem.

In 2003, the world's plastic production exceeded 200 million. Plastics have been included in the four major building materials together with cement, steel, and wood. Plastics are widely used in various aspects of economy, culture, military, and life, among which the packaging industry is the largest application of plastics. According to statistics, an average of 35% of plastics in all countries of the world are used for packaging, 17% for construction, 7% for electronic appliances, and 6% for automobiles. 5% for agriculture and 4% for daily necessities. However, the widely used plastic packaging and agricultural plastic film also bring serious white pollution. In the domestic garbage of large and medium-sized cities in China, the volume of waste plastic products is close to 1/3, and the quality of waste plastics is close to 2 million t/a. Therefore, it is increasingly urgent to develop low-cost, fully degradable green plastics, such as new materials for packaging, mulching, and sand-fixing vegetation.

Sustainable development requirements

The purpose of developing green plastics is to build on the basis of protecting the ecological environment and taking a sustainable development path. In addition, starting from national security needs, we must implement efficient use and alternative research on China's strategic scarce resources such as oil.

The bio-based polymer (bi0base resin) derived from renewable natural biomass resources such as starch, plant straw, chitin, etc. is a kind of green plastic, has good biodegradability, and is rich in raw materials. Its research and development is even more valued by countries. The fundamental starting point for the development of bio-based polymers is that the currently used petrochemical resources are limited, while renewable resources are sustainable. This starting point can be simply described by the Earth's carbon balance map (Figure 1). As can be seen from Figure 1, carbon dioxide is converted into biomass or bio-organic matter by bio-processors such as photosynthesis of plants, and biomass or organic matter is converted to petrochemical resources in one-foot condition, and from biomass or organic. The process of converting materials into petrochemical resources generally takes more than 106 years; petrochemical resources can be changed into polymers, chemical substances, and fuels through the chemical industry, and the cycles of conversion of polymers, chemicals, and fuels into carbon dioxide are approximately It only takes 1 to 10 years. Obviously, the rate of formation of carbon dioxide by products formed by the chemical industry far exceeds the rate at which carbon dioxide is converted back into petrochemical resources through bio-processors. As such processes are repeated, carbon dioxide on Earth will become more and more, and the amount of petrochemical resources will also become less and less, eventually leading to the depletion of oil resources. Bio-based polymers, on the other hand, are directly transformed from renewable biomass or bio-organic materials into polymers, shortening the conversion process from carbon dioxide to polymers, so that the earth's carbon can be maintained in equilibrium.

It can be seen from the perspective of sustainable development that green plastic meets the requirements of sustainable development. Developing green plastic research is of great significance for long-term national security.

(to be continued)