Browsing by Author "Sam Hudson, Committee Member"

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    Hemostatic Mechanisms of Common Textile Wound Dressing Materials
    (2010-05-04) Rush, Tabitha; Marian McCord, Committee Chair; Sam Hudson, Committee Member; Russell Gorga, Committee Member
    The objective of this research is to develop a series of material treatments and modifications, and, using a standardized set of tests, determine the extent of the ability of the modified material to enhance coagulation. This research focuses on materials commonly used in traditional textile based wound dressings; utilizing Streaming Potential studies, Scanning Electron Microscopy (SEM) and Thrombin Assays. The materials tested can be classified into 4 groups: control materials, modified PLA, SAMs treated glass, and TEOS treated materials. The control materials included: spun cotton and rayon yarn; continuous filament Nylon, Polypropylene (PP), and Polyethylene terephthalate (PET); heat cleaned glass (control glass); and PLA staple fibers. Contact angle measurements showed that both the control glass and the PET showed an increase in contact angle when treated with TEOS. This corresponds to a decrease and no improvement, respectively, in thrombogenicity for these materials in the thrombin assay. The remaining materials tested showed no change or a decrease in contact angle after TEOS treatment, and a corresponding increase in thrombogenicity. These results support previous studies that indicate an increase in wettability contributes to the enhancement of coagulation (16). While the streaming potential studies showed no correlation between thrombin formation or contact angle data, these tests provided an important launching platform for future studies utilizing the Streaming Potential Jar. Future work could benefit from the use of more physiologically relevant solutions, such as CaCl2, NaCl, or other blood substitutes (15). While no definitive correlations between test methods were elucidated, the results garnered from this research created a strong launching platform from which future materials research can continue.
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    Novel Supramolecular Polyamides
    (2005-10-23) Saunders, Joshua Daniel; Richard Kotek, Committee Chair; Sam Hudson, Committee Member; Peter Hauser, Committee Member; Christian Melander, Committee Member
    The objective of this research is to use low DP poly(p-benzamide) (PBA) segments, terminated by units forming supramolecular bonds, able to extend the overall DP of the aromatic polyamide. PBA fibers, and the related industrially produced PPTA (Kevlar), exhibit their most interesting ultra-high strength properties only when a considerably large DP (>100) is attained. Use of cumbersome and expensive syntheses and solvents are required to attain DP in the range (~200-300) of industrial interest. Moreover, the fully covalent polymers thus far produced are highly insoluble in common organic solvents. On the other hand, easier processing becomes feasible if the DP of conventional PBA (prepared by the Yamazaki reaction) is increased by supramolecular bonding through ionic or hydrogen bond interactions. The effects of three different binding methods were first investigated on short rigid monomers with promising results the same binding was then used on rigid segments of PBA. The binding methods used two diamine binders triethylenediame (TED) and bipiperidine (Bipip) to form ionic bonds with the monomer, and polymer segments. The last method utilized a 2(6-iso cyanato hexylamino carbonyl amino)-6-methyl-4[1H]pyrimidinone (Upy) end group covalently bonded to the PBA polymer. This end group has the ability to form 4 hydrogen bonds with itself and thus could be used to increase the overall DP of the polymer starting material. This is believed to be the first recorded hydrogen bonded supramolecular interaction in amide type solvents. The novel and revolutionary idea of using low DP segments of PBA to increase the overall DP of polymer could be an industrially viable way to produce the highly sought after industrial polyamides.