Functionalization of chlorogenic acid extracted from honeysuckle and preparation of highly efficient anti-aging NR composites: Experimental and molecular simulation study

Abstract

In this study, chlorogenic acid (CA) was extracted as a natural antioxidant from honeysuckle by ultrasonic method. The CA was quantitatively analyzed by high performance liquid chromatography (HPLC). And the extracted CA was successfully loaded into treated carbon nanotubes (CNTs) by immersion method. An effective strategy to improve the anti-aging property of natural rubber (NR) was proposed by the collaborative use of CNTs-loaded CA (CNTs-CA) and free CA that enabling the NR matrix to maintain a comparatively high concentration of antioxidants for a long period of time. The experiment results showed that the loaded CA was 2.25 times more resistant to migration than that of the free CA after three days of aging. Encapsulation of antioxidant into CNTs inhibited the antioxidant blooming. And the addition of CNTs-CA significantly enhanced the mechanical characteristics of NR. Furthermore, molecular dynamics (MD) simulations elucidated the migration process of the antioxidant in the NR system at the molecular level. The migration kinetics analysis was carried out by MD simulation, and the results showed that the CNTs-CA has more significant migration resistance than free CA. It can be concluded from the calculation results of the binding energy (Ebinding) that the Ebinding of loaded CA and NR was more than three times that of the free CA and NR. In summary, the proposed synergy NR/CA/CNTs-CA system resolved the issue of easy migration and blooming of the antioxidant. Overall, through such efforts, it has become possible to prepare environmentally friendly materials that are durable and resistant to aging.