Title

Application of Wheat Gluten in Polymer Composites and Composite Particleboard

Date of Completion

January 2011

Keywords

Engineering, Chemical

Degree

Ph.D.

Abstract

Wheat gluten (WG) is a complex protein from wheat and has been investigated for potential use in non-food applications, such as WG-based plastics, composites and a binder. In this research, WG was used to prepare: (1) particulate-filled WG composites, (2) natural fiber-filled WG composites, and (3) coconut materials composite particleboard using WG as a binder. ^ In the particulate-filled WG composites, functionalized silica and alumina with various functionalities (e.g. thiol, epoxide, aldehyde, and isocyanate groups) were used as fillers. Two mixing procedures, two-step mixing and in-situ mixing, were used for preparation of the composites and the effect of particle dispersion on the properties of filled WG composites has been studied. More homogeneity of filler particles was observed in the in-situ blended composites, which led to better mechanical properties than those observed in the two-step blended composites. ^ In the natural fiber-filled WG composites, the coconut fiber was used as a filler. Interfacial adhesion between the fiber and WG is crucial for mechanical properties of the composites. Two different chemical surface treatments of the fiber, alkaline treatment and silane treatment, were used to enhance the WG-fiber adhesion. It was found that the WG composite reinforced with the alkaline-followed by silane-treated coconut fiber (ASCCF) significantly improved the mechanical properties. ^ Formaldehyde-free particleboard based on coconut pith (CCP) with three binders, wheat gluten (WG), commercial polyisocyanate (RUBINATE ®1780; RN), and commercial polyurethane (PU), were prepared. Alkali-followed by silane-treated coconut fiber (ASCCF) at 10 wt% fiber was used to reinforce the particleboards. Modulus of elasticity (MOE), modulus of rupture (MOR), tensile strength parallel to surface (TS), water absorption (WA%), thickness swelling (TSW%), and thermal stability of the particleboards were investigated. It was found that the particleboards bound with binders have higher mechanical properties than the binderless particleboard. Among these binders, RN provided superior mechanical and thermal properties, as well as increased water resistance. ^