Engineering Commons^™

Production Of Lignin-Based Phenolic Resins Using De-Polymerized Kraft Lignin And Process Optimization, Homaira Siddiqui

Electronic Thesis and Dissertation Repository

Commercialization of Lignin-based phenol formaldehyde resins (LPF) has been limited due to the increase in curing temperatures and decrease in adhesive strength of LPF compared to conventional phenolic resins. Lignin depolymerization can increase the reactivity of lignin; however, the effect of lignin molecular weight on curing performance of LPF resins has yet to be investigated. This research work examined the optimization of synthesis parameters including percent substitution of phenol with lignin, formaldehyde- to-phenol ratio (F/P), and Mw of lignin to reduce the curing temperature and increase the adhesive strength of LPF. DSC analysis indicated that lignin with Mw ~1200g/mol resulted …

Biomimetic Poly(Ester Amide) Biomaterials For Vascular Tissue Engineering, Darryl K. Knight

Electronic Thesis and Dissertation Repository

The focus of this research was to develop a biomimetic, degradable vascular scaffold that could be considered as part of a tissue-engineered vascular graft strategy. A family of degradable poly(ester amide)s (PEAs) derived from naturally occurring α-amino acids, aliphatic diols and diacids were synthesized to yield PEAs with glass transition temperatures below physiologic temperature ensuring their pliability. Tri-functional amino acids l-lysine or l-aspartic acid were incorporated into the polymer backbone yielding complementary functional handles for subsequent conjugation of growth factors. Higher molecular weight PEAs were obtained using an interfacial polycondensation technique compared with a solution polymerization approach.

Human coronary artery …

Amine Functionalization Of Bacterial Cellulose For Targeted Delivery Applications, Justin Cook

Electronic Thesis and Dissertation Repository

Bacterial cellulose (BC), produced by acetic acid bacteria Gluconacetobacter xylinus, is ideal for delivery and related biomedical functions. It is FDA approved for wound dressings and internal applications, non-toxic to endothelial cells and has little effect on blood profiles. Conjugation of therapeutics to BC can be accomplished through the available alcohol groups of the anhydroglucose units (AGU), making targeted delivery possible. Amine was introduced to BC through a reaction involving epichlorohydrin and ammonium hydroxide. The chemical structure was analyzed using infrared spectroscopy and quantified through pH titration. Conjugation of amine to BC was demonstrated through fluorescein-5’-isothiocyanate (FITC) and bromocresol …

Butyl Rubber-Aliphatic Polyester Graft Copolymers For Biomedical Applications: Synthesis And Analysis Of Chemical, Physical And Biological Properties, Bethany A. Turowec

Electronic Thesis and Dissertation Repository

Biomaterials can be used in a wide variety of medical applications owing to their breadth of characteristics that can be imparted by varying their chemical structures. Butyl rubber (IIR), which is a copolymer of isobutylene (IB) and small percentages of isoprene (IP), is particularly attractive as a biomaterial because of its elastomeric mechanical properties, biocompatibility, impermeability and high damping characteristics. IIR is typically vulcanized through chemical-based crosslinking mechanisms. However, these methods are not acceptable for biological applications. This thesis focuses on the synthesis of IIR-polyester graft copolymers by grafting biodegradable and biocompatible polyesters including poly(caprolactone) (PCL) and poly(d,l-lactide) (PDLLA) to …

Sol-Gel Derived Biodegradable And Bioactive Organic-Inorganic Hybrid Biomaterials For Bone Tissue Engineering, Bedilu A. Allo

Electronic Thesis and Dissertation Repository

Treatments of bone injuries and defects have been largely centered on replacing the lost bone with tissues of allogeneic or xenogeneic sources as well as synthetic bone substitutes, which in all lead to limited degree of structural and functional recovery. As a result, tissue engineering has emerged as a viable technology to regenerate the structures and therefore recover the functions of bone tissue rather than replacement alone. Hence, the current strategies of bone tissue engineering and regeneration rely on bioactive scaffolds to mimic the natural extracellular matrix (ECM) as templates onto which cells attach, multiply, migrate and function.

In this …

Engineering Nanocomposites For Antimicrobial Application, Binyu Yu

Electronic Thesis and Dissertation Repository

In this thesis, active and passive antimicrobial methods have been applied to fabricate antifouling surfaces. In the first study, we reported the synthesis and characterization of neat TiO₂ and Ag-TiO₂ composite nanofilms prepared on silicon wafer by sol-gel method. The synthesized Ag-TiO₂ thin films showed enhanced bactericidal activities compared to the neat TiO₂ nanofilm both in the dark and under UV illumination. The advantage of Ag-TiO₂ nano-composites is to expand the nanomaterial’s antibacterial function to a broader range of working conditions. In the second study, we reported the synthesis, characterization and environmental application of nitrogen …