Enhancing mechanical and anti-aging properties of Eucommia Ulmoides rubber UV shielding film through lignin incorporation.

Ultraviolet (UV) irradiation is a significant cause of material degradation, prompting the need for effective UV shielding materials. Herein, the lignin/Eucommia ulmoides rubber (EUR) composite films were developed to enhance UV shielding, mechanical and anti-aging properties of the EUR film. To improve compatibility, the enzymatic lignin (EL0) was fractionated into EL100 (100 wt% ethanol used as solvent), EL70 (70 wt% ethanol used as solvent), and ELR (residue). Compared to 12.5 % UV transmittance of the EUR film at 300 nm, incorporating lignin into EUR significantly reduced the UV transmittance to <2.0 %. The anti-aging test showed that after 96 h of UV irradiation, the tensile strength of the EUR film decreased from 12.7 to 3.6 MPa, and the elongation at break dropped from 198.5 % to 16.7 %. However, the incorporation of lignin can effectively retard the aging degradation. Specifically, the tensile strength of the EL70/EUR film decreased from 16.2 to 10.2 MPa, while the elongation at break increased from 510.1 % to 208.4 %. As a result, the prepared composite films have potential UV-shielding applications in packaging and agricultural coverings, providing a sustainable approach to utilize lignin and EUR.