Highly improved UV-shielding and mechanical properties of UV-curable epoxy acrylate nanocomposites by incorporating functionalized aramid nanofibers

Introducing nanofillers into UV-curable coatings can not only effectively improve the performance of the coating but also impart new functions to the film. Herein, methacrylate-functionalized aramid nanofibers (mANFs) were constructed by a bottom-up approach, and their influence on the performance of UV-curable epoxy acrylate (EA) coatings was investigated. The microstructure of the EA/mANF nanocomposite was studied using X-ray diffraction and transmission electron microscopy (TEM), which confirmed the homogeneous distribution of mANFs in the matrix. The effect of mANFs on the curing kinetics was investigated. The result showed that the photopolymerization rate and final C = C bond conversion would not be adversely affected until more than 0.1 wt% mANFs were added. The UV–Vis analyses showed that the EA/mANF films maintained high transmittance in the visible light region and exhibited improved UV-shielding performance. The mechanical characteristics of EA/mANF films were significantly improved by mANFs because of strong interactions such as π–π interactions, hydrogen bonds, and chemical bonds between the matrix and mANFs. For the nanocomposite containing 0.025 wt% mANFs, tensile strength and strain at break increased by 53% and 446%, respectively, compared to neat EA. Thus, the introduction of mANFs considerably improved the mechanical performance of UV-curable EA films and expanded their application in the field of UV shielding.