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You searched for +publisher:"North Carolina State University" +contributor:("Dr. Samuel Hudson, Committee Member"). Showing records 1 – 2 of 2 total matches.

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North Carolina State University

1. Gupta, Amit. Novel Approaches to Fiber formation from Hydrogen Bond forming Polymers.

Degree: PhD, Fiber and Polymer Science, 2009, North Carolina State University

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. Advisors/Committee Members: Dr. Samuel Hudson, Committee Member (advisor), Dr. Alan Tonelli, Committee Member (advisor), Dr. Saad Khan, Committee Co-Chair (advisor), Dr. Richard Kotek, Committee Chair (advisor).

Subjects/Keywords: Hydrogen Bonding; Gel Spinning; Nanofibers

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Gupta, A. (2009). Novel Approaches to Fiber formation from Hydrogen Bond forming Polymers. (Doctoral Dissertation). North Carolina State University. Retrieved from http://www.lib.ncsu.edu/resolver/1840.16/4526

Chicago Manual of Style (16th Edition):

Gupta, Amit. “Novel Approaches to Fiber formation from Hydrogen Bond forming Polymers.” 2009. Doctoral Dissertation, North Carolina State University. Accessed April 16, 2021. http://www.lib.ncsu.edu/resolver/1840.16/4526.

MLA Handbook (7th Edition):

Gupta, Amit. “Novel Approaches to Fiber formation from Hydrogen Bond forming Polymers.” 2009. Web. 16 Apr 2021.

Vancouver:

Gupta A. Novel Approaches to Fiber formation from Hydrogen Bond forming Polymers. [Internet] [Doctoral dissertation]. North Carolina State University; 2009. [cited 2021 Apr 16]. Available from: http://www.lib.ncsu.edu/resolver/1840.16/4526.

Council of Science Editors:

Gupta A. Novel Approaches to Fiber formation from Hydrogen Bond forming Polymers. [Doctoral Dissertation]. North Carolina State University; 2009. Available from: http://www.lib.ncsu.edu/resolver/1840.16/4526


North Carolina State University

2. Hunt, Marcus Andrew. Structure and Stability of Columner alpha- and gamma-Cyclodextrin Hydrates.

Degree: MS, Textile Chemistry, 2004, North Carolina State University

α- and γ-Cyclodextrin (CD) recrystallized rapidly from aqueous solution can form columnar structures with only water as the guest molecule. Complementary water vapor sorption and wide-angle x-ray diffractometry (WAXD) experiments were performed on columnar α-CD to elucidate the crystal structure present at varying sorption levels. Equilibrium isothermal water vapor sorption experiments at 40° C revealed that columnar α-CD is unstable above a water activity of approximately 0.67. This was confirmed by WAXD patterns collected over time, which further revealed that columnar α-CD undergoes a phase transformation from columnar to cage structure after approximately 0.25 hours at 40° C and a water activity of 1.0. Upon vacuum-drying at 90° C for 15 hours, γ-CD in the columnar structure undergoes a phase change to an amorphous structure. Complementary water vapor sorption and WAXD experiments were performed on columnar γ-CD in its vacuum-dried and as-precipitated states to elucidate its stability in humid environments and the crystal structure present at varying sorption levels. Isothermal water vapor sorption at 40° C revealed that vacuum-dried γ-CD reverts to cage structure sometime during a sorption experiment at a water activity of 1.0. As-precipitated columnar γ-CD converts to cage structure after 164 hours at a = 1.0 and 40° C. The crystal morphology of as-received CD in the cage polymorph observed by scanning electron microscopy is indicative of its crystal structure, while the crystal morphology of columnar CD is not discernable due to the rapid precipitation method employed. Advisors/Committee Members: Dr. Alan Tonelli, Committee Co-Chair (advisor), Dr. Samuel Hudson, Committee Member (advisor), Dr. C. Maurice Balik, Committee Co-Chair (advisor).

Subjects/Keywords: diffraction; x-ray; absorption

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hunt, M. A. (2004). Structure and Stability of Columner alpha- and gamma-Cyclodextrin Hydrates. (Thesis). North Carolina State University. Retrieved from http://www.lib.ncsu.edu/resolver/1840.16/263

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Hunt, Marcus Andrew. “Structure and Stability of Columner alpha- and gamma-Cyclodextrin Hydrates.” 2004. Thesis, North Carolina State University. Accessed April 16, 2021. http://www.lib.ncsu.edu/resolver/1840.16/263.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Hunt, Marcus Andrew. “Structure and Stability of Columner alpha- and gamma-Cyclodextrin Hydrates.” 2004. Web. 16 Apr 2021.

Vancouver:

Hunt MA. Structure and Stability of Columner alpha- and gamma-Cyclodextrin Hydrates. [Internet] [Thesis]. North Carolina State University; 2004. [cited 2021 Apr 16]. Available from: http://www.lib.ncsu.edu/resolver/1840.16/263.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hunt MA. Structure and Stability of Columner alpha- and gamma-Cyclodextrin Hydrates. [Thesis]. North Carolina State University; 2004. Available from: http://www.lib.ncsu.edu/resolver/1840.16/263

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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