Polylactic acid (PLA) is a new type of biodegradable material made from starch feedstock raised from renewable plant resources such as corn. Glucose is obtained by saccharification of starch raw material, then high purity lactic acid is made by fermentation of glucose and certain strains of bacteria, and then polylactic acid of certain molecular weight is synthesized by chemical synthesis method. It has good biodegradability and can be completely degraded by microorganisms in nature after use, which eventually generates carbon dioxide and water without polluting the environment, which is very beneficial to the protection of the environment and is recognized as an environmentally friendly material.
PLA Advantages
1. Adequate source of raw materials
The raw materials for PLA production are renewable resources such as corn, and there is no need to use precious natural resources such as oil and wood, which will help to protect the depleting oil resources.
2. Superior physical properties
PLA is suitable for various processing methods such as blow molding, thermoplastic, etc. It is easy to process and very widely used. It can be used to process various plastic products from industrial to civil, packaged food, fast food lunch boxes, non-woven fabrics, industrial and civil cloths. Further processing into agricultural fabrics, health care fabrics, wipes, hygiene products, outdoor UV protection fabrics, agriculture and forestry environmental protection, 3D printing, medical field, and automotive craft field is also expanding. In terms of application form, PLA is mainly used in films, sheets, fibers and filaments, and the market prospect is very promising.
3. Food and human safety
PLA also has excellent biocompatibility and its degradation product, L-lactic acid, can participate in human metabolism and has been approved by the U.S. Food and Drug Administration (FDA) for use as medical surgical sutures, capsules for injection, microspheres and implants, etc.
4. Good hardness, gloss and thermoplasticity
Polylactic acid (PLA) film has good air permeability, oxygen permeability and dioxydi-carbon permeability, and it also has the property of isolating odor. Viruses and molds tend to adhere to the surface of biodegradable plastics, so there are concerns about safety and hygiene, but PLA is the only biodegradable plastic with excellent anti-bacterial and anti-mold properties.
5. With full bio-compostable degradability
Polylactic acid (PLA) can be completely degraded by microorganisms in nature after use, eventually generating carbon dioxide and water without polluting the environment, which is very beneficial to the protection of the environment, and is recognized as an environmentally friendly material with relatively low production energy consumption and carbon footprint.
Disadvantages of PLA
1. PLA contains a large number of ester bonds and is poorly miscible with most other plastics.
2. The product has a wide molecular weight distribution and is itself a linear polymer with high brittleness and poor impact resistance.
3. Low heat deflection temperature (generally not heat resistant unless modified and crystallized in a hot mold).
4. Must be in industrial composting conditions to degrade in 3-6 months, natural environment degradation is slow, long cycle, more difficult to control.
5. Higher price than traditional plastic.
It is worth noting that the advantages and disadvantages of PLA are relative when used, for example, when used in the field of packaging materials, high permeability becomes a disadvantage that needs to be overcome, and when used in the field of textiles, the hard and brittle characteristics will also become a problem that needs to be solved. In terms of mechanical properties, the tensile strength and modulus of PLA are comparable to PET and higher than PS and PP, which are basically benchmarked to replace PET and PP in some applications in use.
PLA is one of the most popular biodegradable materials for domestic and international research, with food packaging, disposable tableware and medical materials as its three most popular applications. With lactic acid of natural origin as the main raw material, PLA has excellent biodegradability and biocompatibility, and its life-cycle load on the environment is significantly lower than that of petroleum-based materials, which is considered to be the most promising green packaging material.
As a new type of pure bio-based material, PLA has a great prospect of market application. Its good physical properties and the environmental protection of the material itself will certainly make PLA more widely used in the future.
