Polylactic acid (PLA) is a novel biodegradable material made from starch raw materials proposed from renewable plant resources such as corn. The starch raw material is saccharified to obtain glucose and then fermented by glucose and certain strains to produce high-purity lactic acid and then synthesize polylactic acid with a specific molecular weight by chemical synthesis. It has good biodegradability and can be completely degraded by natural microorganisms after use, eventually producing carbon dioxide and water without polluting the environment. It is beneficial to protecting the environment and is recognized as an environmentally friendly material.
Advantages of PLA
1- Adequate sources of raw materials
The raw materials for the production of polylactic acid are renewable resources such as corn, without using precious natural resources such as petroleum and wood, so it will play a very important role in protecting the increasingly depleted petroleum resources.
2- Superior physical properties
Polylactic acid is suitable for various processing methods, such as blow molding and thermoplastic, and is easy to process and widely used. It can be used to process various plastic products from industry to civilian use, packaged food, fast food lunch boxes, non-woven fabrics, and industrial and civilian fabrics. And then processed into agricultural fabrics, health care fabrics, rags, sanitary products, outdoor anti-ultraviolet fabrics, agriculture, forestry, environmental protection, 3D printing, medical fields, and automotive technology fields are also constantly expanding. From the perspective of application form, polylactic acid is mainly film, sheet, fiber, and silk, and the market prospect is very promising.
3- Food and human safety
Polylactic acid also has excellent biocompatibility, and its degradation product, L-lactic acid, can participate in human metabolism. It has been approved by the US Food and Drug Administration (FDA) and can be used as medical surgical sutures, injection capsules, microspheres, and implants. Plants, etc.
4- Good hardness, gloss, and thermoplasticity
Polylactic acid (PLA) film has good air permeability, oxygen permeability, and carbon dioxide permeability, and it also has the property of isolating odor. Viruses and molds are easy to attach to the surface of biodegradable plastics, so there are doubts about safety and hygiene. However, polylactic acid is the only biodegradable plastic with excellent antibacterial and anti-mildew properties.
Fully bio-compostable and degradable
Polylactic acid (PLA) can be completely degraded by microorganisms in nature after use and finally generate carbon dioxide and water without polluting the environment. This is very beneficial to the protection of the environment. It is recognized as an environmentally friendly material, and its production energy consumption and carbon footprint are relatively low.
Disadvantages of PLA
- Polylactic acid contains a lot of ester bonds, and it has poor blend-ability with most other plastics.
- The product has a wide molecular weight distribution and is a linear polymer with high brittleness and poor impact resistance.
- Low thermal deformation temperature (generally only heat-resistant if it is crystallized with a thermal mold after modification).
- It must be degraded in 3-6 months under the condition of industrial composting. The degradation in the natural environment is slow, the cycle is long, and it isn't easy to control.
- The price is higher than traditional plastics.
It is worth noting that the advantages and disadvantages of polylactic acid are relative when used. For example, in the field of packaging materials, high air permeability becomes a shortcoming that needs to be overcome. When used in the textile field, the characteristics of hardness and brittleness will also become a problem that needs to be solved. Question. In terms of mechanical properties, the tensile strength and modulus of polylactic acid are comparable to those of PET and higher than those of PS and PP. In use, it is basically a standard replacement for some applications of PET and PP.
PLA is one of the most researched biodegradable materials at home and abroad. Food packaging, disposable tableware, and medical materials are its three popular application fields. PLA uses natural lactic acid as the main raw material. It has good biodegradability and biocompatibility. Its life cycle load on the environment is significantly lower than that of petroleum-based materials. It is considered to be the most promising green packaging material.
As a new type of pure bio-based material, PLA has great market application prospects. Its good physical properties and the environmental protection of the material itself will inevitably make PLA more widely used in the future.