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Biodegradable Bags

Biodegradable bags in laboratory

1. What are biodegradable bags?
    1.1 Difference between compostable and biodegradable bags
    1.2 What are materials of biodegradable bags?
    1.3 Bioplastic degradation
2. What is biodegradable plastic?
    2.1 Advantages of biodegradable plastics
    2.2 Types of biodegradable plastics
    2.3 Examples of biodegradable plastics
3. How to buy biodegradable bags?

What are biodegradable bags?

Biodegradable bags are plastic bags that are degraded under natural conditions such as soil and/or sand, and/or specific conditions such as composting conditions or anaerobic digestion conditions, or aqueous cultures, caused by the action of naturally occurring microorganisms such as bacteria, molds, and algae, and eventually completely degraded into carbon dioxide (CO2) or/and methane (CH4), water (H2O) and mineralized inorganic salts of the elements they contain, as well as new biomass.

Biodegradablebags are bags that can be broken down by bacteria or other living organisms. There are approximately 500 billion to 1 trillion plastic bags that are used worldwide each year.

Difference between compostable and biodegradable bags

In typical parlance, the term biodegradable means something different from compostable. Biodegradable simply means that the object is capable of being broken down by bacteria or other organisms, whereas compostable in the plastics industry is defined as being able to break down in an aerobic environment maintained under specific controlled temperature and humidity conditions. Compostable means capable of biodegradation in a compost pile, making the material visually indistinguishable and decomposing into carbon dioxide, water, inorganic compounds, and biomass at a rate consistent with that of known compostable materials.

The inclusion of "inorganic material" precludes the end product from being considered compostable or humus, which is purely organic material. In fact, the criteria required for a plastic to be called compostable under the ASTM definition is that it must disappear at the same rate as other things that are already known to be compostable under the traditional definition.

Biodegradable plastic bags can be made "oxo-biodegradable" by being made from a common plastic polymer (i.e., polyethylene) or polypropylene and mixed with an additive that causes the polymer (polyethylene) to degrade and then biodegrade due to oxidation.

What are materials of biodegradable bags?

Most bags made from plastic are made from corn-based materials, such as polylactic acid blends. Today, biodegradable plastic bags are as strong and reliable as conventional (mainly polyethylene) bags. Many bags are also made of paper, organic materials, or polycaprolactone.

Bioplastic degradation

At present, there is no unified international standardized definition of biodegradable plastic bags, but the definition of biodegradable plastic bags refers to the significant changes in the chemical structure of biodegradable plastic bags under specific environmental conditions, and the physical properties of biodegradable plastic bags can be measured by standard test methods. The molecular chain of biodegradable plastic bags can have microorganisms biodegrade them in waste disposal systems or natural rings in the environment, eventually converting them into carbon dioxide (or methane) and water, and entering into a combined biological cycle process that is completely absorbed by the environment, leaving no polymer.

Degradation mechanism of biodegradable plastic bags

Most synthetic, pure polymers will be resistant to microbial attack. However, some additives (such as plasticizers, lubricants, pigments and antioxidants) can reduce this ability. Residual fatty acids such as stearates from plasticizers can be degraded by microorganisms, leading to damage to the polymer surface, properties, and even infrastructure. The degradation of natural polymers by microorganisms is known to be accomplished by enzymes and proteins produced during the biosynthesis process. These enzyme proteins can be localized in the cell wall or in the protoplasmic structure of the cell. Some enzymes can submerge into the surrounding environment, while others remain within the cell and are released only when the cell is mechanically lysed or disrupted. Enzymes have only a highly specific catalytic capacity for biochemical reactions and can proceed rapidly under appropriate physiological conditions.

Biodegradable plastic bags are degraded by the following two methods.
a. Biophysical degradation
When microorganisms attack and erode polymer materials due to biological cell growth and polymer components are hydrolyzed, ionized, or protonated and then split into oligomeric fragments. The polymer is degraded and the molecular structure remains unchanged, which is the degradation process of polymer biophysical action.
b. Biochemical degradation
Due to the direct action of microorganisms or enzymes, polymers are broken down or oxidized into small molecules, which eventually break down into carbon dioxide and water.

What is biodegradable plastic?

There are two types of biodegradable plastics: complete biodegradable plastics and destructive biodegradable plastics.

Disruptive biodegradable plastics currently include mainly starch-modified (or filled) polyethylene PE, polypropylene PP, polyethylene PVC, and polystyrene PS.PE, PP, PVC, PS, etc.

Fully biodegradable plastics are mainly made from natural polymers (e.g. starch, fibrin, chitin) or agricultural by-products through microbial fermentation or synthesis of polymers with biodegradable properties. Thermoplastic starch plastics, aliphatic polyesters, polylactic acid, and powders/polyethylenes are all examples of these plastics.

Natural substances such as starch-based biodegradable plastics currently include the following products: polylactic acid (PLA), polyhydroxyalkanoates (PHA), powdered plastics, bioengineered plastics, biopolymers, and bioproducts. Biological engineering plastics, and bio-common plastics (renal olefins and polyethylene). Advantages of Fully biodegradable plastics are as follows.

a. Full biodegradable plastic bags are made of animal straw, starch, etc. There is no harm to the human body and the environment, a kind of packaging plastic bags, discarded, in the role of sunlight, water, and other biological environments, can be self-synthesis, whether it is not harmful to people or the environment, belong to the green packaging plastic bags.

b. Fully biodegradable plastic bags are used to high standards. They are solvent and oil resistant and can be heat-sealed. This kind of packaging plastic bag is used for catering and other aspects, clean and hygienic.

c. In terms of quality, the full biodegradable plastic bags have good tension, strong stretch, high softness, and good hand-feel, which is a better packaging plastic bags.

d. Full biodegradable plastic bags have a good anti-static function and do not absorb dust.

Advantages of biodegradable plastics

Compared to white waste plastics which will disappear only in hundreds of years, under composting conditions, the fully biodegradable products can be decomposed by microorganisms more than 90% in 30 days. Biodegradable plastic bags can generally be decomposed within a year, and the Olympic environmental plastic bags can even start to decompose 72 days after disposal. Non-biodegradable plastic bags will take 200 years to degrade them.

Types of biodegradable plastics

A. Biodegradable plastics of natural polymer materials

The natural polymer raw materials of biodegradable plastics are of two types: plant and animal. Plant sources include starch, cellulose, lignin, its derivatives, etc., while animal sources include gelatin, chitin, prion acetylated chitin, chitosan, and its derivatives. The modification of natural polymer materials by making them thermoplastic is the main method to prepare biodegradable plastics of natural polymer materials type. In the 18th century, celluloid, made from digested cellulose, was the first example of a plastic made from a natural polymer.
PLA is made from lactic acid, which is synthesized mainly from biomass resources such as corn starch and is a representative of bio-based biodegradable plastics. There are three main routes for synthesizing PLA: first, direct condensation of lactic acid; second, synthesis of lactic acid into propylene glycol ester and then catalytic ring-opening polymerization; and third, solid-phase polymerization. The synthesis route of domestic PLA is mostly based on the second route.
PHA is a polyhydroxy fatty acid ester, which is a new type of completely biodegradable thermoplastic with biocompatibility, biodegradability, and animal edibility.

PHA is a large family of materials, more than 150 different monomer structures have been found, but only a few of them have been produced on a large scale.

B. Petrochemical-based biodegradable plastics

Dibasic diol copolyester
Although PBS and PBSA have been developed earlier, due to their performance limitations, the market usage is not as high as that of PBAT, and the current global production is mainly based on PBAT.
Carbon Dioxide Copolymer (PPC), Polycaprolactone (PCL)
Other petrochemical-based biodegradable plastics are PPC, PCL, etc.

Examples of biodegradable plastics

According to the application fields, the uses of biodegradable plastics are textile fiber, packaging, agriculture, forestry, fishery and animal husbandry, automotive, 3D augmentation, etc.

Textile fibers

The current production capacity of PLA fiber in China is about 15 kt/year. It has the advantages of both natural fiber and synthetic fiber, and its excellent core absorption makes its products have the characteristics of good resilience, strong drapability, and high comfort.

Daily-use film and bags

Biodegradable plastic film bags are mainly based on PBAT, most co-blended PLA and other materials, after processing, in the domestic garbage bags, plastic shopping bags, daily-use plastic bags, etc. have begun to be used on a large scale, in the fresh packaging film also have applications. In addition, PLA-type biaxially oriented film is used as cling film, which has an excellent effect on the freshness of vegetables and fruits.

Sheet and thermoformed products

PLA extruded sheets are being used in fresh food, salad, and food packaging after thermoforming, such as transparent fruit boxes and egg cartons.

Foam products

PLA foam products have been used in many packaging trays and boxes for fresh food and vegetables in supermarkets, and starch-based plastics and PLA foam cushioning materials are used in the packaging of electrical and electronic machines and precision machinery.

In addition, biodegradable plastics have been used in automotive parts and 3D printing products.

How to buy biodegradable bags?

ANTITECK provide lab equipment, lab consumable, manufacturing equipment in life sciences sector.
If you are interested in our biodegradable bags or have any questions, please write an e-mail to, we will reply to you as soon as possible.

    AntiTeck Life Sciences Limited

    A1-519, XingGang GuoJi, Yingbin Road, Huadu, Guangzhou, China, 510810
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