DEVELOPING NEW FUNCTIONAL NANOMATERIALS FOR APPLICATIONS IN ADVANCED POLYMER COMPOSITES

This thesis presents methods to make novel functional nanomaterials and to incorporate them into advanced polymer composites. In two studies, nanoparticle systems are developed in biopolymer materials and explored for their potential in water treatment applications. Methods are optimized to make nanoparticles in lignocellulose without damaging the biopolymer material, then Natural Fiber Welding (NFW) is used to engineer a novel, sustainable fiber-welded Pd-Cu catalyst reactor to effectively reduce the contaminant nitrate. Next, a new Pd-In nanoparticle system is introduced that is 10-times more reactive (than analogous Pd-Cu) and completely air stable. Using a custom-built yarn-coating system and a novel, scalable NFW process, the more robust Pd-In catalysts are fiber-welded as a shell-coating onto the surface of hundreds of meters of linen yarn. This fiber-welded catalyst yarn is integrated into a novel water treatment reactor optimized for nitrate reduction. During four months and more than 180 h of nitrate reduction tests, the fiber-welded catalyst reactors are successfully evaluated in ultrapure water, and in four raw or (partially) treated drinking water and wastewaters. This research demonstrates an innovative, scalable approach through NFW to design and implement robust, sustainable lignocellulose-supported catalysts with enhanced reactivity capable of water purification in complex waters. In a third study, a new nanoparticle flame retardant is developed using phosphoric acid and multi-walled carbon nanotubes (MWCNTs). These novel, phosphorus-functionalized MWCNTs (P-MWCNTs) are evaluated for their flame-retardant potential in polystyrene and poly (methyl methacrylate). This work reveals methods to maximize phosphorus loading onto MWCNTs and shows how P-MWCNTs are synergistic flame-retardant additives when properly dispersed into synthetic polymer matrices. In a fourth study, a series of silanized cellulose nanofibers (Si-CNFs) are developed and evaluated for potential as NFW coatings onto lignocellulose yarn. Using NFW, the Si-CNFs are fiber-welded as shell-coatings onto textile fibers. Thermogravimetric analysis reveals how the Si-CNFs improve the underlying textile fiber’s thermal stability by as much as 25 °C by delaying their onset of thermal degradation during pyrolysis. More importantly, this work unveils the potential for NFW as a green engineering method to improve the thermal stability of textile fibers