1. Daily necessities: item packaging bags

The most commonly used fields of biodegradable plastics are in the daily life field, including packaging of daily necessities (food bags, supermarket shopping bags, fast food tableware), express packaging (plastic packaging bags, plastic tape, disposable plastic woven bags), cosmetics/skincare packaging materials, and other daily consumption fields. Degradable plastics PLA (polylactic acid) and PBAT (polyadipic acid/butylene terephthalate) are the most widely used biodegradable plastics in the field of degradable plastics.

Biodegradable plastics undergo a hydrolysis reaction after water molecules enter the degradable plastic in the early stage of degradation. Single PBAT plastic has rigid ester bond in its molecular structure, which makes it difficult for water molecules to enter; PLA plastic, on the other hand, is prone to internal decomposition due to water molecules entering. The higher the PLA content, the faster the plastic decomposition time.

Due to the use of bio based raw materials such as corn, PLA has a higher price, while PBAT uses petroleum based raw materials with a lower price. Therefore, the cost of PLA is higher than that of PBAT, and PBAT plastics are more widely promoted in industry. In the process of biodegradation, such as biodegradable packaging bags, they are basically composed of bio based plastic PLA and PBAT. In the case of industrial composting, they have appropriate temperature and humidity and can be completely decomposed into water and carbon dioxide, without pollution to the environment.

2. Food and beverage takeout: degradable lunch box

The application of degradable plastics in food and beverage delivery has gradually increased with the promotion of national policies and regulations. The most commonly used types of takeout packaging lunch boxes are traditional plastics, followed by pulp or paper based film lunch boxes, and then biodegradable lunch boxes. Due to the low cost, low cost, and wide range of use of traditional plastics, biodegradable plastics are advancing in the direction of replacing traditional plastics.

Non degradable plastics in food packaging can be replaced by paper based materials, pulp materials, or degradable plastics such as polylactic acid PLA. In response to the characteristics of Chinese cuisine in China, there are many oily and watery soups, and the application scenarios of degradable plastic packaging are relatively wider. However, after the breakthrough of degradable plastic technology in China, production capacity continues to increase, and the supply of degradable plastic is in short supply, with high costs.

Therefore, for Western cuisine, tea and coffee, as well as some Chinese dishes and staple foods, paper based materials will still be an important choice to replace traditional plastic products, while degradable plastics will be a green and environmentally friendly trend for future development.

3. Medical surgery: consumables and tissues

The medical device industry is a key industry in the application of biodegradable raw materials. At present, PHA and PCL in degradable plastics have good thermoplasticity, molding processability and biocompatibility. They are mainly used for degradable surgical suture, fracture fixation equipment, human organ repair, artificial skin, histiocyte engineering, etc. The use of degradable surgical suture can avoid the pain of patients' suture removal, and the use of implanted biodegradable repair equipment can reduce the risk of rejection and infection.

China's "14th Five Year Plan" and "Made in China 2025" both proposed to focus on the development of high-value medical devices such as fully biodegradable vascular stents. In the future, the application of biodegradable plastics in the medical field will flourish. At present, degradable plastics are widely used in surgical suture; In terms of degradable implantable devices, foreign countries have relevant technologies and production; In terms of biodegradable coronary stents, Chinese medical enterprises have launched biodegradable coronary stents developed using PLA, marking a new development in China's research on biodegradable plastics. In the future, technological breakthroughs and cost issues will still be a major challenge for the application and development of the biomedical industry.

4. Agricultural planting: degradable plastic film

The mechanism of agricultural plastic film covering is to improve the growth and development conditions of crops and resist abnormal natural environments by increasing soil temperature, preventing ground water loss, inhibiting grass and weeds, inhibiting salt and protecting seedlings, increasing the uniformity of light under the canopy, and increasing reflected light.

Agricultural plastic mulch is a polymer compound that cannot be independently degraded and has a long degradation time. Long term adhesion to the soil can damage the soil texture and organic matter, leading to reduced crop yield. The additives in the plastic mulch will be released into the soil with increasing humidity, causing pollution to food crops, thereby damaging food sources and human health. The final degradation products of degradable plastic film are carbon dioxide and water, which can control plastic film pollution from the source and ensure crop yield. Therefore, it can balance environmental protection and economic benefits, and has good application prospects.