Environmentally friendly plastics

Environmentally friendly plastics: material innovation for sustainable development

Environmentally friendly plastics are a new type of material developed on the basis of traditional plastics, aimed at reducing negative impacts on the environment and achieving resource recycling. It has become an important solution to address "white pollution" by improving materials, production processes, or recycling systems to reduce pollution risks while maintaining the practicality of plastics.

1、 Classification and characteristics of environmentally friendly plastics

Environmentally friendly plastics can be divided into three categories based on their environmental characteristics: biodegradable plastics, recycled plastics, and bio based plastics, each with unique properties and application scenarios.

degradable plastic

Degradable plastics can be decomposed by microorganisms into carbon dioxide, water, and harmless substances in natural environments such as soil, seawater, and composting conditions, avoiding long-term residual pollution.

Polylactic acid (PLA): Made from plant starch such as corn and sugarcane, it has high transparency and mechanical properties similar to traditional plastics. It is suitable for packaging films, disposable tableware, etc., but its heat resistance is poor (usually not exceeding 60 ℃).

Polybutylene adipate/polybutylene terephthalate (PBAT): It has good flexibility and can improve brittleness when blended with PLA. It is commonly used in agricultural film, garbage bags, etc. It can be completely degraded under composting conditions for 3-6 months.

Polyhydroxyalkanoates (PHA): produced by microbial fermentation, with excellent biocompatibility, can be used in the medical field (such as surgical sutures), and can also degrade in seawater environment, suitable for marine related packaging.

recycled plastic

Recycled plastics are made by recycling waste plastics through cleaning, crushing, melting, and reshaping, achieving resource recycling and reducing crude oil consumption.

Physical recycled plastics: Directly processing waste plastics, with slightly lower performance than virgin plastics, can be used to make trash cans, recycled fiber fabrics, etc.

Chemical recycled plastics: By chemically depolymerizing plastics into monomers, they can be re polymerized and have properties similar to raw materials. They are suitable for high demand scenarios such as food packaging, and recycled PET bottles have been widely used in beverage packaging.

Biobased plastics

Biobased plastics are made from renewable biomass such as starch, vegetable oils, and straw, reducing dependence on fossil resources and partially being biodegradable.

Starch based plastics: Low cost, easy to process, often blended with other materials to make packaging materials, but have poor water resistance.

Bio based PE/PET: Made from ethylene or terephthalic acid produced through biomass fermentation, with performance consistent with traditional PE/PET and recyclability, reducing carbon emissions.

2、 Production process and technological breakthroughs of environmentally friendly plastics

The production of environmentally friendly plastics focuses on greening and low carbonization, reducing energy consumption and pollutant emissions during raw material acquisition and processing.

Raw material innovation

Degradable plastics and bio based plastics can break free from dependence on crude oil and utilize carbon resources stored by plant photosynthesis. For example, the production of PLA uses corn starch as raw material, which is fermented and converted into lactic acid, and then polymerized to form polymer materials. The entire process reduces carbon emissions by 30% -50% compared to traditional plastics.

Recycled plastics achieve precise separation of different types of plastics through efficient sorting techniques such as infrared spectroscopy recognition, providing high-quality raw materials for subsequent recycling processing and avoiding impurities affecting product performance.

Process optimization

Enzymatic catalysis technology is widely used in the synthesis of biodegradable plastics, such as using lipase to catalyze the polymerization reaction of PBAT, reducing reaction temperature and energy consumption, and minimizing the use of chemical catalysts.

Green solvents and catalysts are used in the chemical regeneration process, such as using supercritical water technology in PET depolymerization, which does not require organic solvents and has higher reaction efficiency and improved product purity.

3、 Application scenarios of environmentally friendly plastics

Environmentally friendly plastics have penetrated into multiple fields such as packaging, agriculture, daily necessities, and healthcare, gradually replacing traditional plastics.

Packaging field: Biodegradable plastic bags and meal boxes are popular in food delivery and supermarkets; Biobased PET bottles are used for packaging beverages and cosmetics, while recycled plastic films are used for express packaging.

In the agricultural field, biodegradable agricultural film solves the problem of traditional film residue, automatically degrades after crop harvest, and avoids soil compaction; Biobased fertilizer bags can degrade upon contact with soil, reducing waste.

Daily necessities: starch based garbage bags, disposable tableware made of PLA, clothing made of bio based fibers, etc., balancing practicality and environmental friendliness.

In the medical field, sutures made of PHA can be absorbed by the human body after wound healing, without the need for secondary surgery to remove them; Degradable drug carriers can accurately release drugs and naturally degrade them.

4、 Challenges and Future Trends

Despite the rapid development of environmentally friendly plastics, they still face many challenges:

Cost issue: The production process of bio based plastics and chemically recycled plastics is complex, with higher costs than traditional plastics, which limits their large-scale application.

Performance limitations: Some biodegradable plastics have deficiencies in temperature resistance, water resistance, and mechanical properties, such as PLA, which is prone to deformation at high temperatures and difficult to use for holding hot drinks.

Imperfect recycling system: Mixing biodegradable plastics with traditional plastics can affect recycling efficiency, and consumers have insufficient understanding of the classification of different environmentally friendly plastics, leading to increased difficulty in recycling.

In the future, environmentally friendly plastics will develop towards the direction of "high performance, low cost, and full lifecycle environmental protection":

Material compounding: By using blending and copolymerization techniques to improve the defects of a single material, such as PLA and PBAT composite, it has both good strength and flexibility.

Intelligent degradation: Develop environmentally responsive biodegradable plastics that only initiate degradation under specific humidity and temperature conditions (such as in soil) and maintain stability during storage and use.

Closed loop recycling system: Combining blockchain technology to achieve full lifecycle traceability of plastics, recording the entire process from production, consumption to recycling and regeneration, improving recycling efficiency and transparency, and promoting the "production consumption regeneration" circular model.

The development of environmentally friendly plastics is not only about material technology innovation, but also requires policy support (such as plastic restriction orders, subsidy policies), collaborative efforts of enterprise participation and consumer awareness enhancement. With the advancement of technology and the improvement of the industrial chain, environmentally friendly plastics will become a key material for achieving the "dual carbon" goal and sustainable development, promoting the transformation of human society towards a green and low-carbon model