Cellulose nanofiber (CNF), derived from renewable resources, is a good candidate to reinforce transparent plastics without sacrificing their transparency, owing to its size on the nano-meter scale, reflective index similar to the plastics’, excellent mechanical property, and low density. This study investigates effects of CNF on optical, viscoelastic, and thermal properties of CNF reinforced poly(methyl methacrylate) (PMMA). CNF/PMMA with different CNF contents and different types of PMMA were prepared through a solvent casting method with a low toxic and inexpensive solvent, acetone, and compression-molded to create nanocomposite films. The films were characterized using a transmission electron microscope, ultraviolet–visible (UV-Vis) spectrophotometry, dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). It was found that CNFs were well-dispersed in the PMMA matrix and the viscoelastic and thermal properties of the PMMA were increased by the addition of CNF, while maintaining a high degree of transparency and increasing attenuation capability of ultraviolet light
