Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Master of Engineering Science

Program

Mechanical and Materials Engineering

Abstract

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.

Summary for Lay Audience

Cellulose fiber offers an environmentally friendly, sustainable reinforcement option for plastics and can be acquired from a wide range of plant sources along with some animal sources. A cellulose nanofiber (CNF) is a cellulose fiber which has been broken down from a macroscale to a nanoscale. The size reduction creates a fiber with an exceptionally high mechanical properties, providing a unique reinforcement option. Furthermore, CNF exhibits high optical transparency because the fiber diameter is much smaller than the wavelength of visible light. Poly(methyl methacrylate) (PMMA) is a transparent plastic and rivals glass and polycarbonate (PC) for optical transparency. PMMA is lighter than glass and less expensive than PC. However, PMMA possesses relatively low mechanical and thermal properties, which hinders its use in wider applications. In this study, the mechanical and thermal properties of two types of PMMAs were increased by adding CNFs, while maintaining a high degree of their transparency.

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