Polylactic Acid
Polylactic acid has good thermal stability, a processing temperature of 170-230°C, good solvent resistance, and can be processed in a variety of ways, such as extrusion, spinning, biaxial stretching, injection blow molding, etc. In addition to being biodegradable, products made of polylactic acid have good biocompatibility, gloss, transparency, feel and heat resistance.
Advantages
A. Polylactic acid (PLA) is a new type of biodegradable material, made from starch raw materials from renewable plant resources (such as corn). Starch raw materials are saccharified to obtain glucose, which is then fermented with glucose and certain strains to produce high-purity lactic acid, and then polylactic acid of a certain molecular weight is synthesized by chemical synthesis. It has good biodegradability and can be completely degraded by microorganisms in nature after use, eventually generating carbon dioxide and water, without polluting the environment. This is very beneficial to protecting the environment and is a recognized environmentally friendly material.
B. Good mechanical and physical properties. Polylactic acid is suitable for various processing methods such as blow molding and thermoplastics. It is easy to process and has a wide range of applications. It can be used to process various plastic products from industry to civilian use, packaged food, fast food lunch boxes, non-woven fabrics, industrial and civilian fabrics. It can then be processed into agricultural fabrics, health fabrics, rags, sanitary products, outdoor UV protection fabrics, tent fabrics, floor mats, etc., and the market prospects are very promising.
C. Good compatibility and degradability. Polylactic acid is also widely used in the medical field, such as producing disposable infusion equipment, non-disassembly surgical sutures, etc., and low-molecular polylactic acid as a drug sustained-release packaging agent.
D. In addition to the basic characteristics of biodegradable plastics, polylactic acid (PLA) also has its own unique characteristics. The strength, transparency and resistance to climate change of traditional biodegradable plastics are not as good as ordinary plastics.
E. The basic physical properties of polylactic acid (PLA) are similar to those of petrochemical synthetic plastics, that is, it can be widely used to manufacture various application products. Polylactic acid also has good gloss and transparency, which is equivalent to the film made of polystyrene, which is not available in other biodegradable products.
F. Polylactic acid (PLA) has the best tensile strength and ductility. Polylactic acid can also be produced by various common processing methods, such as melt extrusion molding, injection molding, blown film molding, foaming molding and vacuum molding. It has similar molding conditions as widely used polymers. In addition, it also has the same printing performance as traditional films. In this way, polylactic acid can be made into a variety of application products to meet the needs of different industries.
G. Polylactic acid (PLA) film has good air permeability, oxygen permeability and carbon dioxide permeability, and it also has the property of isolating odors. Viruses and molds easily attach to the surface of biodegradable plastics, so there are concerns about safety and hygiene. However, polylactic acid is the only biodegradable plastic with excellent antibacterial and antifungal properties.
H. When polylactic acid (PLA) is incinerated, its combustion calorific value is the same as that of incinerating paper, which is half of that of incinerating traditional plastics (such as polyethylene), and incinerating polylactic acid will never release toxic gases such as nitrides and sulfides. The human body also contains lactic acid in monomer form, which shows the safety of this decomposable product.
Industry Application
Disposable Products
The absolutely harmless nature of polylactic acid to the human body makes it uniquely advantageous in the field of disposable products such as disposable tableware and food packaging materials. Its ability to be completely biodegradable also meets the high environmental protection requirements of countries around the world, especially the European Union, the United States and Japan. However, disposable tableware processed with polylactic acid raw materials has defects such as poor heat resistance and oil resistance.
Biomedical Field
The biomedical industry is the earliest field where polylactic acid has been applied. Polylactic acid is highly safe for the human body and can be absorbed by tissues. In addition to its excellent physical and mechanical properties, it can also be used in the biomedical field, such as disposable infusion tools, non-disassembly surgical sutures, drug relief packaging agents, artificial fracture internal fixation materials, tissue repair materials, artificial skin, etc.
The recycling technology of PLA plastic mainly includes two methods: physical recycling and chemical recycling
Physical recycling method
Physical recycling is the process of washing, crushing, melting and remolding the discarded PLA plastic. This method does not need to change the chemical structure of PLA, so it can maintain its original performance. The advantages of physical recycling are relatively simple process, low cost, and no new pollutants are introduced. However, physical recycling also has some challenges, such as the difficulty of separating and purifying discarded PLA plastic, and the performance of the recycled material may be slightly reduced.
Chemical recycling method
Chemical recycling is to decompose the discarded PLA plastic into monomers or oligomers through chemical reactions, and then polymerize them into new PLA plastic. This method can recycle PLA more thoroughly and restore its original performance. The specific steps of chemical recycling include:
Pretreatment: Wash and crush the discarded PLA plastic.
Depolymerization: Decompose PLA into monomers or oligomers by chemical methods.
Purification: Purify the depolymerization product to remove impurities.
Repolymerization: Repolymerize the purified monomers or oligomers into new PLA plastics
