Some frequently asked questions about plastic bags in life

1. What materials are plastic bags made of, and what are its characteristics?
Plastic bags are made from different materials but are mainly made from petroleum-derived polyethylene (PE) and polypropylene (PP) resins along with a number of other chemical additives. Polyethylene plastic used to produce plastic bags usually has two types: Low Density Polyethylene (LDPE) and High Density Polyethylene (HDPE). Plastic bags have the following characteristics: good mechanical strength, transparency, smooth surface, waterproof but poor air permeability.

HDPE is often used to produce plastic bags with medium clarity, surface gloss, poor flexibility, certain stiffness, easy to fold, and a clear rustling sound when rubbed. so often called foam bags). Common HDPE foam bags are garbage bags, plastic bags for grocery stores, supermarket bags and small shops. Plastic bags making LDPE film have clarity, smooth surface, and glossier than HDPE foam bags. Thanks to its toughness and smoothness, the production cost of bags is higher than that of HDPE bags, but the quality of plastic bags will be better. Common LDPE bags are large-sized PE bags, used to store goods of relative weight, often printed advertising products, printing logos, and branding for businesses.
Plastic bags made from PP plastic have higher mechanical strength, quite hard, so they are not flexible, difficult to stretch along like HDPE or LDPE. In particular, PP bags have smoothness, high surface gloss, and better mechanical strength. In addition, PP material is resistant to gas and water, so it is often used as a bag for food, for preserving goods, or for packing pallets of goods - food.

2. In today's daily life and production, people are increasingly using plastic bags, so how does that affect our health and living environment?
When manufacturing plastic bags, people have to use chemical additives such as dyes, heavy metals (lead, cadmium, ..), plasticizers, etc., which are hazardous to health. of human. At a temperature of 70-80oC, toxic additives contained in plastic bags will dissolve into food. Among them, some plasticizers can damage and degenerate peripheral nerves and spinal cord; They are toxic to the testicles and cause some birth defects if they are regularly exposed to them.

If using plastic bags to store acidic foods such as pickles, pickled tomatoes, hot foods, the plasticizers in the plastic bags will separate from the plastic ingredients and cause food poisoning. When soaked in pickles, lactic acid in melons and tomatoes will dissolve some metals that can cause cancer.

Besides, plastic bags made from PE and PP are both very difficult materials to decompose in normal landfill conditions (it takes hundreds of years to completely decompose), so the use of plastic bags will affect the environment. bad for the human environment. The existence of plastic bags in the environment will seriously affect the soil and water because the plastic bags mixed with the soil will prevent oxygen from passing through the soil, causing soil erosion, making the soil degraded, not porous, poor quality. nutrients, thereby slowing plant growth. Plastic bags stuck deep in sewers and canals also clog causing sewage stagnation and flooding. Sewage stagnation points will be the breeding ground for many disease-causing bacteria. Besides, waste from plastic bags also detracts from the beauty of the environment.

3. How to properly destroy plastic bags? What are the consequences if destroyed incorrectly?
Consumers need to classify waste as plastic bags immediately after use for environmental companies to collect and destroy or re-manufacture to ensure environmental safety. Do not arbitrarily bury it because it will pollute the soil and water sources, and also do not burn it because when burning plastic, it will produce carbon dioxide, methane, which are substances that cause greenhouse effects and even produce dioxins (in Agent Orange) is an extremely toxic substance that seriously affects human health and the living environment.

4. Any advice for users of plastic bags to minimize the harm it brings?
To minimize the harmful effects of plastic bags, users should limit the use of ordinary plastic bags by using reusable and biodegradable bags when shopping; Do not use cheap, colored plastic bags to store food, especially not to store hot and sour foods. After using, do not arbitrarily burn or bury, but separate plastic bags for the environmental company to collect and destroy according to regulations.

Assoc.Prof.Dr. Le Duc Giang - Faculty of Chemistry, Vinh University