Enhancing Lignin Dispersion in Natural Rubber Latex via Silica Hollow Microsphere Loading With Complementary Compatibilization by Epoxidized Natural Rubber

ABSTRACT Addressed the challenges of poor dispersion and interfacial incompatibility of alkali lignin (AL) in natural rubber (NR) matrices which is arising from AL's high polarity, an innovative wet mixing synergistic strategy was developed using silica hollow microspheres (SHM) as physical carriers for AL and epoxidized natural rubber (ENR) as an interfacial compatibilizer. The effects of different SHM:AL mass ratios on the performance of the resulting SHM/AL/NR composites were systematically investigated. Microstructural characterization revealed that AL achieved optimal dispersion in the NR composite at an SHM:AL mass ratio of 1:3. In the SHM/AL/NR composite with 50 wt% carbon black (CB) replaced by SHM/AL (1:3), the tensile strength reached 26.7 MPa. The retention rates of tensile strength and elongation at break were 97.4% and 89.9%, respectively, indicating excellent mechanical properties and anti‐aging performance. Furthermore, ENR was incorporated as an interfacial compatibilizer to enhance the compatibility between SHM/AL and the rubber matrix. At an ENR content of 20 phr, the tensile strength of the SHM/AL/ENR/NR composite was further increased to 27.8 MPa. In comparison with the 20CB/20ENR/NR composite, its tensile strength retention and elongation retention rose by 12.1% and 22.6%, respectively, whereas the tensile strength remained nearly unchanged.