This dissertation focuses on the versatility and integrity of a novel, ultrasoft polycarbonate polyurethane (PCPU) by the introduction of nanoparticles and lithium salts. Additionally, the research takes into account the use of electrospinning as a technique to create PCPU and polyimide (PI) fibers. These polymers are of interest as they offer a wide range of properties and uses within the medical and industrial fields. An industrial batch of an ultrasoft thermoplastic polyurethane (TPU) was synthesized using a two-step process. The first was to create an end capped pre-polymer from methylene bis (4-cyclohexylisocyanate), and a polycarbonate polyol made up of 1,6- hexanediol and 3-methyl-1,5-pentanediol. The second step was done by reacting the pre-polymer with an excess of the polycarbonate polyol with a chain extender, 1,4-butanediol. Biocompatibility testing such as USP Class VI, MEM Elution Cytotoxicity and Hemolysis toxicology reported that PCPU showed no toxicity. This novel type of polyurethane material targets growing markets of biocompatible polymers and has been used for peristaltic pump tubing, but also can be utilized as balloon catheters, enteral feeding tubes and medical equipment gaskets and seals. This material is ideal for replacing materials such as soft plastisols containing diethylhexyl phthalate for use in biomedical and industrial applications. After extensive characterization of this polymer system another dimension was added to this research. The addition of nanoparticles and nanofillers to polyurethane can express enhanced mechanical, thermal and adhesion properties. The incorporation of nanoparticles such as nanosilica, nanosilver and carbon black into polyurethane materials showed improved tensile strength, thermal performance and adhesion properties of the PCPU. Samples were characterized using contact angle measurements, Fourier transform spectroscopy (FTIR), differential scanning calorimetry (DSC), parallel plate rheology and tensile testing. The second chapter entails the fabrication and characterization of PCPU nanofibers and nanomembranes through a process known as electrospinning. The resulting PCPU nanomembranes showed a crystalline peak from the WAXS profile which is due to electrospun and solution strain induced crystallinity. The PCPU nanocomposite nanomembranes displayed increased thermal stability and an increase in tensile performance at higher weight percent. The nanomembranes were investigated using contact angle measurements, thermogravimetric analysis (TGA), DSC, WAXS, SAXS and tensile testing. The final chapter focuses on investigating the rheological properties of PCPU/lithium electrolytes as well as transforming an unprocessable polyimide powder into a nanomembrane. The PCPU/ lithium composite electrolyte showed an increase in the activation energy and conductivity, while the PI/lithium showed increased conductivity over time. Dynamic mechanical analysis and four-point probe was used to investigate the samples.

Four novel high performance soft thermoplastic polyurethane elastomers utilizing methylene bis(4-cyclohexylisocyanate) as a hard segment, 1,4 butanediol as a chain extender and modified low crystallinity carbonate copolymer as a soft segment were synthesized. The samples were characterized by infrared spectroscopy (FTIR), tensile, elongation, hardness, abrasion resistance and atomic force microscopy (AFM). SAXS data shows evidence of an interdomain "center-to-center" distance of 45Å. DSC traces show evidence of one glass transition temperature and a weak melting region. DMA analysis reveals a low temperature secondary relaxation and the glass to rubber transition followed by a rubbery plateau. All samples demonstrated the ability to maintain excellent physical and mechanical properties in hardness below 70 Shore A. Thermoplastic polyurethanes in this study do not possess surface tackiness usually observed in soft polyurethanes. Biocompatability testing showed no toxicity of these samples as indicated by USP Class VI, MEM Elution Cytotoxicity and Hemolysis toxicology reports. This novel type of polyurethane material targets growing markets of biocompatible polymers and can be utilized as peristaltic pump tubing, balloon catheters, enteral feeding tubes and medical equipment gaskets and seals. Polyimides are a family of engineering polymers with temperature stability, high polarity and solvent resistance. These high-performance materials are used in aerospace applications, in the production of semi-dry battery binders, and in a host of other high temperature demanding situations. However, their glass transition and melt temperatures are characteristically very high and close to one another, making them difficult to melt process and limiting them to thin film formulations from their polyamic acid precursors. Here, a new series of thermoplastic polyether-polyimides (PE-PIs) are synthesized by incorporating a polyetherdiamine monomer to reduce rigidity and break up an otherwise fully aromatic backbone as seen with most conventional polyimides. It will be shown that control of the stoichiometric ratio between the aromatic 4,4'-methylenebis(2,6-dimethylaniline) and aliphatic polyetherdiamines relative to PMDA (pyromellitic dianhydride), along with the molecular weight of the polyetheramine, can be used to tune the Tg to best balance between temperature performance and processability.