Fabrication of high-expansion, fully degradable polylactic acid-based foam with exponent oil/water separation

Polylactic acid (PLA) foam is widely regarded as an effective substitute for petroleum-based foams. However, the fabrication of high-expansive, lightweight, highly hydrophobic foams for oil/water separation remains a challenge. Here, an innovative method was developed to improve the foaming ability of PLA by introducing silane modified alkaline lignin (m-LA), and a lightweight PLA foam with a high expansion ratio, high porosity, and high hydrophobic performance was successfully developed. The crystallization behavior, rheological properties, pore morphology, and oil/water separation performance of foams were evaluated. The results show that m-LA not only improves the crystalline properties of PLA, but also plays an important nucleation role during the foaming. m-LA increased the foaming ratio of PLA to 40.17 times, and reduced the apparent density of the foam to only 0.0303 g cm −3 . The PLA foam has exponent hydrophobicity. The water contact angle is up to 130.0°, and the adsorption capacity of various organic solvents is 5.17–12.44 g g −1 , because the surface energy of LA is reduced by silane modification. This study provides a new insight into the development of environment-friendly PLA foams for oil/water separation applications.