Development of Biodegradable Compositions Based on Poly(Lactic Acid) With Reduced Moisture Absorption

Poly(lactic acid) (PLA) is a biodegradable, biocompatible, and thermoplastic aliphatic polyester with considerable potential for various applications. Its favorable physical and mechanical properties enable processing using conventional equipment, making it suitable for the manufacturing of packaging materials, textile fibers, technical products, and medical devices. However, the presence of polar carbonyl groups in the molecular structure of PLA renders the polymer hygroscopic, for example, water molecules are easily adsorbed. This moisture adsorption represents a challenge during processing, often resulting in defects in PLA and its composite materials. To mitigate these issues, hydrophobization additives serve as an alternative or complement to drying processes for enhancing polymer performance. In this regard, a range of PLA composites has been synthesized with the incorporation of oxides, specifically silicon oxide (SiO 2 ) and calcium oxide (CaO), as well as organic anhydrides like maleic anhydride and succinic anhydride. Experimental analysis reveals that the inclusion of these hydrophobization additives does not markedly alter the physical and mechanical properties of the composites, which closely resemble those of unmodified PLA. The mechanisms of moisture mitigation vary between different additives. In the case of SiO 2 , water molecules are predominantly adsorbed onto its surface through physical interactions. Conversely, other hydrophobization additives chemically capture water via direct chemical reactions. Long‐term testing demonstrated that after 3 weeks, the water content in most PLA‐based hydrophobized composites remained below the critical threshold of 0.2 wt.%, which is considered optimal for maintaining the desired physical and mechanical characteristics of the material.