High -temperature polystrackic acid (PLA) is one of the more degradable plastics that are more degradable for research and applications. Its raw materials come from renewable plant fibers, corn, agricultural by -products, etc., which have good biodegradability. PLA has excellent mechanical properties and is similar to polypropylene plastic. It can replace PP and PET plastic in some fields. At the same time, it has good gloss, transparency, feel, and certain bacteriostatic.
1. The production status of high -temperature polystraphin PLA
At present, there are two types of PLA’s synthesis routes. One is the direct aggregation method. The lactic acid is about to dewater and shrink at high temperature and low pressure. The production process is simple and the cost is low, but the product molecular quality is uneven and the actual application effect is poor. The other is that the propylecly polymerization of Cyrne is legal, which is the current mainstream production method. The specific process is as follows.
PLA is legal, with high production efficiency, good product quality, and high cost.
2. De degradability of high -temperature polystraphin PLA
PLA is more stable at room temperature, but it is easy to quickly degrade CO2 and water in a slightly higher temperature environment, acid to the ministry ring cup, and microbial environment. Therefore, the PLA products can be used to use the environment and fillers to be safely used during the validity period, and it can be degraded at a time after abandonment.
The factors that affect PLA degradation include molecular quality, crystalline state, micro structure, environmental temperature and humidity, pH value, light time and environmental microorganism.
PLA and other materials are mixed with other materials that can affect degradation speed. For example, PLA adds a certain amount of wooden powder or corn straw and fiber to greatly accelerate the degradation rate.
3. resistance to high temperature polystrackic acid PLA
Obstruction refers to the ability to prevent gas and water steam through the material. Division of blocking materials is very important for packaging materials. At present, the most common cutting plastic bag on the market is Plapbat composite material. The resistance of the PLA film can be widening the application field.
The factors that affect PLA blockage mainly include their own factors (molecular structure and crystalline state) and external factors (temperature, humidity, external force).
1. Heating the PLA film will reduce its blockage, so PLA is not suitable for food packaging as a food that needs to be heated.
2 PLA stretching within a certain range can increase resistance. When the tensile ratio increases from 1 to 6.5, the crystallization of PLA is greatly improved, so the obstruction is improved.
3. Adding some blocking (such as clay and fiber) to the PLA substrate can improve the obstruction of PLA. This is because blocking the bending path of the water or gas penetration of small molecules.
4. Pailoring treatment on the surface of the PLA film can improve resistance.
4. PLA’s mechanical performance
PLA has a good strength. The mechanical properties are similar to PP, but the lack of toughness is easy to bend and deform, and it usually needs to be toughened and modified. In order to ensure the biodegradability of PLA, PLA and other plastic performance are usually mixed with biodegradable resin. PBAT, PBS, PCL, natural rubber and other substances can improve PLA toughness.
5. PLA’s optical performance
PLA has the rare transparency and gloss of other degradable plastic, which is equivalent to glass paper and PET, especially suitable for use (visual packaging, good decoration effect. Generally, the transparency and lightness of PLA do not need to be improved. It should be noted that other other in other is in other. Do not reduce its good transparency as much as possible to ensure its packaging visuality and decoration effect.
PLA transparent packaging box
6. PLA’s thermal performance
The thermal stability of PLA materials is equivalent to PVC, but lower than PP, PE and PS. The processing temperature is generally controlled between 170 ~ 230 ° C. It is suitable for injection, stretching, extrusion, blowing, 3D beating, etc. Essence
PLA tableware
In actual processing, the PLA crystallization rate is slow and generally requires modification. Due to the slow and low crystallization rate, the heat deformation temperature of the PLA is low, which limits its application on the packaging of heat -filled or thermal sterilization products.
In order to improve the PIA crystal rate and crystallinity, PLA’s optical purity can be improved as much as possible during production. Antuction treatment is also a way to improve PA crystallinity. In addition, it can be added with nuclear agents to improve the crystallization behavior, improve its crystallinity, thereby improving thermal deformation temperature, and improving its heat resistance.
High temperature 3D printing PLA
7. PLA’s antibacterial performance
PLA can form a weak acidic environment on the surface of the product, which has the effects of bacteriostatic and mildew. If the auxiliary antibacterial agent is used to reach more than 90%of the antibacterial rate, it can be used for antibacterial packaging of the product.
PLA cardiovascular stent, antibacterial PLA is often used in the medical field
Commonly used inorganic antibacterial agents are mainly silver, copper, zinc and other metals. The commonly used organic Hango bacteria include vanadal or ethyl vanadal formation compounds. The food safety of other antibacterial agents needs to be studied. Generally organic The antibacterial agent is poor and the validity period is short.
8. PLA’s electrical performance
PLA can prepare conductive particles such as carbon black (CB), carbon nanotubes (CNTS), carbon fiber (CFS), or stone ringne. Conductive polymer composite materials are widely used in anti -static plastic, electromagnetic shielding materials, self -control temperature heat -thermal materials, positive temperature coefficient materials, and environmental sensitive devices.
CPCS, which is based on PLA, also has degradation and biocompatibility. It can be used for special anti -static packaging, electromagnetic shielding packaging, and intelligent packaging. For example, PLA base conductive polymer can be used for gas or liquid sensors to detect food quality information.
Post time: Oct-08-2022