With the continuous advancement of science and technology and the improvement of living standards, the discharge of oily wastewater from industrial production and daily life has become increasingly severe, becoming a significant contributor to ecological environmental degradation. Among diverse treatment strategies, physical adsorption using functional oil-absorbing materials has attracted considerable attention due to its eco-friendliness, structural design reliability, and operational simplicity.
Poly(lactic acid), as a representative biodegradable polymer, has attracted considerable attention owing to its renewable origin and environmentally benign degradation products. Its moderate hydrophobicity and affinity for ester groups endow PLA with significant potential for oil absorption applications. However, during supercritical CO₂ foaming, PLA suffers from low melt strength, making it susceptible to cell collapse and rupture, thereby compromising its oil absorption performance. To address these challenges, PBAT and talc were incorporated into the PLA matrix to enhance its foaming performance.
In this study, researchers from Zhengzhou University prepared PLA/PBAT/Talc ternary composites via melt blending, and successfully fabricated PLA-based porous foam materials with high volume expansion ratio and high open-cell content using batch supercritical CO₂ foaming. The effects of talc content on phase morphology, thermal behavior, and rheological properties were systematically investigated.
Results demonstrated that with 10 wt% PBAT and 3 wt% talc introduced into the PLA matrix, the PLA/PBAT-T3 foam achieved a volume expansion ratio exceeding 45 and an open-cell content of 85%. Talc-induced refinement of PBAT domains expanded the interfacial area, promoting interfacial debonding during cell growth. Rheological tests showed that talc incorporation enhanced storage modulus and complex viscosity by restricting molecular chain mobility, thereby improving melt strength and stabilizing cell growth.
Foaming temperature significantly influenced cellular structure. At 90°C, open-cell content was merely 2.5%, but increased to approximately 85% when temperature was elevated to 115°C, as reduced melt viscoelasticity facilitated cell wall rupture. Cyclic compression tests demonstrated that foam fabricated at 100°C exhibited the lowest permanent deformation (22% after 10 cycles), indicating superior structural integrity compared to neat PLA foam (31.5%) and PLA/PBAT foam (23.5%).
Contact angle measurements confirmed hydrophobic and oleophilic characteristics, with water contact angles ranging from 110° to 125°. Oil absorption tests revealed equilibrium capacities of 22.2 g·g⁻¹ for silicone oil and 13.4 g·g⁻¹ for cyclohexane. A significant correlation was established, revealing that oil absorption capacity is directly proportional to the multiplication of volume expansion ratio and open-cell content.
After 10 consecutive absorption-desorption cycles, the PLA/PBAT-T3 foam retained over 85% of its initial capacity, with absorption loss less than 15%, significantly lower than that of comparative materials. This enhanced performance is attributed to the synergistic effect between the unique cellular structure and large specific surface area of layered talc filler.
This work provides a viable strategy for engineering biodegradable and recyclable oil-sorbent materials, while advancing the application potential of PLA-based composites in sustainable environmental remediation technologies.
DOI
10.1007/s11705-026-2626-x