Hydrogen bond forming polymers such as aliphatic polyamides and polyvinyl alcohol are important engineering plastics with good mechanical properties, high melting point and good chemical resistance. However, any further attempt at improving their mechanical properties gets thwarted due to the presence of intermolecular hydrogen bonding. Many approaches have been attempted in the past to suppress hydrogen bonding in aliphatic polyamides and have met with little or no success. These include, plasticizing the structure, dry spinning, wet spinning, gel spinning, and zone drawing/annealing. We have employed a new technique that involves the dry-jet wet spinning and drawing of GaCl3/nylon 66 complex. This new method allows traditional low draw ratios for nylon 66 to be increased by disrupting the interchain hydrogen bonded network. Fibers with a high modulus were obtained when high molecular weight nylon 66 was used. Further, we have also reviewed the concept of thermoreversible gelation and its application for gel spinning of ultra high molecular weight polyethylene fibers. We developed high strength and modulus nylon 6 and PVA fibers from the gels of these polymers in N-methyl pyrrolidinone. High molecular weight is essential for achieving more drawing of polymer chains which leads to high molecular orientation. Electrostatic spinning or electrospinning has received considerable research attention in recent years. It involves the application of an electric filed to a polymer solution or melt to facilitate production of fibers in the sub-micron down to nanometer range. We have investigated the complexation of GaCl3 with nylon 6 and developed porous nanofibers via the technique of electrospinning. Pores are generated by removal of salt from the as spun nanofibers via dipping in water. Researchers have tried in the past using a highly volatile solvent, or selective removal of one polymer from a bicomponent nanofiber for developing pores in nanofibers. However, using a metal salt proved to be a simple and fast approach for generating pores in electrospun nanofibers.
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-08152008-135907 |
| Date | 18 August 2008 |
| Creators | Gupta, Amit |
| Contributors | Dr. Samuel Hudson, Dr. Alan Tonelli, Dr. Saad Khan, Dr. Richard Kotek |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-08152008-135907/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dis sertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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