Industry News
The macroscopic properties of materials are a reflection of their microscopic structure. The brittleness of polylactic acid (PLA) is determined by its molecular and aggregated characteristics, and coating additives provide an effective direction for its modification.
The First "Lock": The "Rigid Body" of the Molecular Chain
The methyl side groups of the PLA molecular backbone act like small, hard lumps regularly bound to a flexible molecular chain, directly leading to two major problems:
- Restricted chain segment movement, macroscopically manifested as material rigidity and lack of flexibility;
- High glass transition temperature, causing chain segments to "freeze" at room temperature, unable to dissipate impact energy. This necessitates strict control of compatibility when PLA is compounded with coating additives.
The Second "Lock": The "Rigid Skeleton" of Crystallization
During processing and cooling, polylactic acid (PLA) molecular chains partially form regular crystals. While this improves strength and heat resistance, it poses a threat to toughness:
- The crystals themselves are hard and brittle, easily becoming stress concentration points that trigger cracks. Specific coating additives can improve this problem by controlling the crystallization process.
- The amorphous regions between crystals are "anchored," restricting chain segment movement. Introducing coating additives can enhance their mobility through interfacial interactions.
The Third "Lock": The "Lightning Propagation" of Microcracks
PLA is extremely sensitive to notches; surface scratches and internal impurities can all become stress concentration points. Once microcracks form, they propagate rapidly due to the lack of energy dissipation mechanisms, leading to fracture. Interfacial modified coating additives can improve the surface density of the material, reduce notches, and delay crack propagation.
In summary, the "brittleness" of PLA is due to its weak energy absorption capacity, not insufficient strength. As multifunctional modifiers, coating additives have become a research hotspot due to their potential application in optimizing its microstructure and improving toughness. This concludes the article. For more information, please follow "Qingtian New Materials".
Suzhou Qingtian is a professional company specializing in coatings and ink additives for 15 years. Our main products include dispersants, leveling agents, defoamers, ice flower paint, electroplating silver resin, texture powder, and wax powder. Please feel free to contact us if you have any needs. Qingtian's hotline is 18020278196. We look forward to your call!
