Can biodegradable plastic polymers exhibit barrier properties to moisture?

Biodegradable plastic polymers can exhibit a certain degree of water barrier performance, but this performance is usually not as efficient as traditional plastics. The following are some factors and improvement methods related to the water barrier performance of biodegradable plastic polymers:
Polymer type: Different types of biodegradable polymers have different water barrier properties. For example, polylactic acid (PLA) has good water barrier properties, but it is still not as good as traditional plastics such as polyethylene (PE) or polypropylene (PP).
Material structure: The molecular structure and crystallinity of polymers can affect their water barrier properties. Polymers with high crystallinity typically have better barrier properties.
Additives and coatings: The water barrier performance of biodegradable plastics can be improved by adding certain fillers or coatings. For example, adding nanoclay, starch, or coating with biodegradable coatings can significantly improve the barrier performance of materials.
Multi layer structure: By combining biodegradable plastics with high barrier materials in a multi-layer structure, the water barrier performance can be significantly improved. This structure is commonly used in food packaging to extend the shelf life.
Copolymerization and blending modification: Through copolymerization or blending modification, the physical properties of biodegradable plastics, including water barrier properties, can be improved. For example, blending polylactic acid (PLA) with polycaprolactone (PCL) can improve the toughness and barrier properties of PLA.
It should be noted that although the water barrier performance of biodegradable plastics can be improved through the above methods, their performance is often not completely comparable to traditional plastics. For applications that require high barrier properties, such as certain food and medical product packaging, traditional plastics or a combination of multi-layer structures may still be required to meet the requirements.
Overall, through reasonable design and modification, biodegradable plastic polymers can exhibit water barrier properties to a certain extent, meet various application needs, and have environmental advantages.