The synthesis process and properties of polylactic acid (PLA)

The synthesis process of polylactic acid (PLA)

There are mainly two synthetic pathways for polylactic acid (PLA) : the direct polycondensation of lactic acid
Ring-opening polymerization of (DPC) and lactide(ROP).

The direct condensation polymerization of lactic acid is formed by the direct condensation polymerization of lactic acid as the monomer. This method does not require the addition of a catalyst. Only lactic acid and solvents are needed for the polymerization reaction. The process flow is relatively simple and the operation is convenient, which can reduce production costs and improve production efficiency.

Lactide (LA) ring-opening polymerization is a reaction in which lactide is used as the monomer and undergoes two processes of ring-opening and polymerization to form a linear high-molecular polymer. This method efficiently converts cyclic monomers into high-molecular-weight polymers through ring-opening polymerization reactions, with good controllability of the reaction. The resulting polylactic acid (PLA) can meet its wide application requirements in the field of biodegradable materials. 

The characteristics of polylactic acid (PLA) :

Polylactic acid (PLA), as a bio-based and biodegradable material, possesses a series of unique properties:
Biodegradability
Polylactic acid (PLA) can be decomposed by microorganisms in natural environments or under specific conditions, eventually converting into carbon dioxide and water, thereby reducing environmental pollution.
Biocompatibility
Polylactic acid (PLA) can be gradually degraded in the human body through hydrolysis, and the lactic acid monomers produced participate in the body's metabolism, eventually generating carbon dioxide and water and being excreted from the body.
Processability
Polylactic acid (PLA) can be formed through various processing methods such as injection molding, blown film, and extrusion. The processing temperature is moderate and it is easy to operate.
Customizability: Through modification, such as adding plasticizers, fillers, and reinforcing agents, the performance of polylactic acid (PLA) can be adjusted to meet different application requirements.
Thermal stability: The melting point of polylactic acid (PLA) is typically between 155 and 185°C, and it exhibits good thermal stability within a certain temperature range.
Barrier performance
Polylactic acid (PLA) has certain barrier properties against certain gases, such as oxygen and carbon dioxide.