Biodegradable mulch refers to a type of plastic mulch that can be degraded by microorganisms under natural conditions. After microorganisms such as bacteria, fungi and actinomycetes erode the plastic film, due to the growth of cells, the polymer components are hydrolyzed, ionized or protonated, mechanically damaged, and split into oligomer fragments. Enzymes secreted by fungi or bacteria decompose or oxidatively degrade water-soluble polymers into water-soluble fragments, generating new small molecular compounds, and finally decomposing into CO2 and H20.
Biodegradable mulch film is a new type of ground cover film, which is mainly used for ground cover to increase soil temperature, maintain soil moisture, maintain soil structure, prevent pests from attacking crops and diseases caused by certain microorganisms, thereby promoting plant growth.
Classification
There are many classification methods for biodegradable mulch, which can be divided into the following types according to different classification methods:
1. According to the degradation mechanism and damage form, biodegradable plastic film can be divided into two types: complete biodegradable plastic film and additive biodegradable plastic film. Completely biodegradable mulch film is a plastic film composed of substances that can be completely decomposed by microorganisms. The substances are mainly derived from starch, cellulose, chitosan and other polysaccharide natural materials. The final products of degradation are CO2 and H20, which can be It is completely absorbed by nature and will not cause secondary pollution to the environment. Its main varieties are polylactic acid (PLA), polycaprolactone (PCL), polyhydroxybutyrate (PUB) and so on. In addition, polyvinyl alcohol can also be completely degraded by water and microorganisms. Additive biodegradable mulch film is made by adding natural or synthetic polymers or biodegradation accelerators, processing aids, etc. The additive biodegradable mulch film is mainly composed of general plastic, starch, compatibilizer, auto-oxidant and processing aid. Its typical variety is polyethylene starch biodegradable mulch.
2. According to the raw materials, biodegradable mulch film can be divided into starch-based biodegradable mulch film, cellulose-based biodegradable mulch film, blending and copolymerization mulch film of cellulose and other natural polymer materials, lignin-based biodegradable mulch film, etc.
3. According to the molding process, biodegradable mulch can be divided into film type, injection type, sheet type and foam type.
