In today’s society, as people’s environmental awareness increases, the demand for sustainable materials is becoming more and more urgent. Polylactic acid (PLA), as a new type of biodegradable material, has received widespread attention due to its unique environmental protection characteristics and broad application prospects.
PLA can not only effectively reduce dependence on traditional petroleum-based plastics, but also significantly reduce environmental pollution, providing a new solution for sustainable development.
This article will comprehensively degrade the definition, characteristics, application fields and future development trends of PLA, helping you to gain a deeper understanding of this important environmentally friendly material.
Table of Contents
What Is Pla
PLA, or Polylactic Acid or Polylactide, is a thermoplastic aliphatic polyester. Its chemical formula is (C3H4O2)n.
PLA is not a plastic because it is made from plant starch, a bio-based polymer made from renewable resources such as corn and sugar cane. Unlike traditional plastics, which are extracted from petroleum. The production process and ultimate biodegradability of PLA make it an attractive alternative to traditional plastics.
What Is Made of Pla
The production process involves first converting plant starch into glucose, then converting glucose into lactic acid through fermentation, and finally converting lactic acid into PLA through polymerization.
- Starch to sugar: Starch is extracted from plants such as corn and converted into sugars such as glucose.
- Sugar fermentation to lactic acid: Sugars are converted into lactic acid using microbial fermentation.
- Lactic acid to lactide: Lactic acid is chemically converted into lactide, a cyclic diester.
- Lactide polymerization to PLA: Lactide is polymerized into high molecular weight polylactic acid by epoxy ring-opening polymerization.
The Difference Between Pla and Traditional Plastics:
Raw material difference: Traditional plastics are mainly made from fossil resources such as petroleum, while PLA comes from renewable plant resources.
Environmental impact difference: PLA has good biodegradability and can be decomposed into carbon dioxide and water by microorganisms under specific industrial composting conditions, which is environmentally friendly. Traditional plastics are difficult to degrade naturally and are prone to cause white pollution.
Properties of PLA
Physical properties:
PLA is a thermoplastic material with good processability and can be formed by extrusion, injection molding, 3D printing and other methods.
Its mechanical strength is similar to that of some traditional plastics and can meet a variety of application requirements.
The glass transition temperature of PLA is about 60 degrees Celsius, so its heat resistance is relatively poor.
Biodegradability:
The biodegradation of PLA needs to be carried out under specific industrial composting conditions. It can be quickly decomposed by microorganisms under an environment of 60 degrees Celsius and humidity above 90%.
In ordinary natural environments, the degradation rate of PLA is very slow, and it may even take several years to completely degrade.
Biodegradation and Recycling of PLA
PLA’s biodegradability is one of its biggest advantages.
Biodegradation mechanism: Under composting conditions, microorganisms will decompose PLA into carbon dioxide and water.
Composting conditions: Appropriate temperature, humidity and microorganisms are the key to PLA degradation.
Recycling methods:
Industrial composting: PLA products are sent to professional industrial composting facilities for processing.
Biorecycling: An emerging technology that uses microorganisms or enzymes to decompose PLA and recycle its monomers.
The plastic classification symbol of PLA is.
PLA (Polylactic Acid) Advantages and Disadvantages
| Feature | Advantages | Disadvantages |
|---|---|---|
| Source | Renewable resources (corn starch, sugarcane) | |
| Environmental Impact | Biodegradable (industrial composting), lower carbon footprint | Requires specific industrial composting conditions |
| Processing | Easy to process (3D printing, extrusion, injection molding) | |
| Mechanical Properties | Moderate strength, stiffness | Can be brittle, lower durability compared to some plastics |
| Thermal Properties | Low heat resistance, softens at relatively low temperatures | |
| Applications | Packaging, 3D printing, medical, textiles | |
| Cost | Becoming more competitive | May be higher than some traditional plastics |
| Moisture | sensitive to moisture | |
| Recycling | Requires separate recycling stream |
Applications of PLA
3D printing:
PLA is one of the commonly used materials in the field of 3D printing. It is widely used in prototyping and model making due to its advantages such as easy printing, good molding effect and environmental protection.
Packaging industry:
PLA can be used to make food packaging, degradable compostable bags, disposable tableware, etc., reducing the pollution of traditional plastics to the environment.
Textile industry:
PLA can be made into fibers for the manufacture of textiles.
Medical industry:
PLA has good biocompatibility and can be used to make medical sutures, bone nails, etc.
Agriculture:
PLA can be used to make agricultural mulch, which is degradable and beneficial to the protection of the soil environment.
Other emerging applications:
With the continuous development of PLA technology, its application areas are constantly expanding, such as electronic product housings, automotive interiors, etc.
Environmental Significance of PLA
Reduce dependence on fossils: PLA’s raw materials come from renewable plant resources, which helps reduce the consumption of fossil resources such as oil.
Reduce carbon emissions: The carbon emissions during the PLA production process are much lower than those of traditional plastics, which helps to mitigate climate change.
Reduce plastic pollution: PLA is biodegradable and can effectively reduce the pollution of plastic waste to the environment.
Conclusion
As a biodegradable material made from renewable resources, PLA is of great significance in reducing environmental pollution and addressing climate change. Although PLA still has some limitations, with the continuous advancement of technology and the continuous expansion of its application fields, it will play an increasingly important role in future sustainable development. Let us look forward to the green future brought by PLA!
FAQ
Is PLA biodegradable?
Yes, PLA can be biodegraded under industrial composting conditions. PLA can be decomposed into carbon dioxide, water and humus under high temperature and the action of specific microorganisms.
How can PLA be recycled?
PLA can be recycled through industrial composting and chemical recycling. Chemical recycling can depolymerize PLA into lactic acid, which can then be used to produce new PLA materials.
Does PLA produce microplastics?
Yes, PLA may also produce microplastics. Studies have shown that if PLA plastic waste cannot be completely degraded, the continued release of PLA microplastics will cause more serious PLA microplastic pollution to the environment.
How quickly does PLA degrade?
PLA degrades more slowly than other bio-based degradable plastics. In the natural environment, PLA takes a long time to completely decompose.
Can PLA be home composted?
PLA can only be effectively degraded under industrial composting conditions. The temperature and humidity of home composting are usually not high enough to completely decompose PLA.
Is PLA carbon neutral?
PLA is made from biomass materials such as corn, and plants absorb CO2 during their growth. Therefore, even if PLA is directly incinerated, it will not actually increase the CO2 content in the atmosphere.
