Browsing by Author "Peter Hauser, Committee Member"

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Co-Presence of Durable Flame Retardant and Repellent Nano-Finishes.
(2010-05-13) Halbur, Jonathan; Xiangwu Zhang, Committee Chair; Jeffrey Joines, Committee Member; Henry Boyter, Committee Member; William Oxenham, Committee Member; Peter Hauser, Committee Member
Durable and Non-Toxic Topical Flame Retardants for Cotton and Cotton Blends
(2008-04-26) Mathews, Marc Christopher; Brent Smith, Committee Co-Chair; Peter Hauser, Committee Member; Kristin Thoney, Committee Member; Henry Boyter, Committee Member
Flame retardant chemicals were used as topical finishes on cotton and cotton blended fabric. Comparison of flame resistance and durability of non-bromine/non-antimony flame retardants were explored based on flame resistance testing and physical testing results. Three 100% cotton fabrics and 3 cotton blended fabrics were used. Twenty one different commercially available flame retardants were used as topical finishes on all fabric types. Fabrics were treated and tested at 0, 5, 10 and 25 washes. Final results show that two of the phosphorus flame retardants were durable to 25 washes. Physical testing results show that there were undesirable side effects from the two durable topical treatments. The two phosphorus based flame retardants outperformed the bromine⁄antimony flame retardants and the non-treated samples in flame resistance.
Durable Flame Retardant and Antimicrobial Nano-Finishing
(2010-06-01) Dalton, Edward Arthur; Peter Hauser, Committee Member; Martin King, Committee Member; Xiangwu Zhang, Committee Chair; Henry Boyter, Jr., Committee Member
Due to the costs associated with processing, materials, and the inherent difficulties in applying durable flame retardant and/or antimicrobial finishes, alternatives to conventional finishing methodologies are one of the focal points in todayâ€™s textile research and industry. We, therefore, propose a new nano-finishing, involving the use of conventional flame retardants, titanium dioxide (TiO2) nanoparticles, and multifunctional silanes, to replace conventional methodologies as this new finishing combines the functionality of flame retardant and antimicrobial performance, each feeding off of the synergistic properties of the other. In this work, 100% cotton and 80/20 polyester/cotton fabrics were treated with a combination of Degussa P25 TiO2 nanoparticles, tetrakis(hydroxymethyl)phosphonium chloride and urea flame retardants, and silane cross-linkers (such as tetraethoxysilane). These fabrics were prepared using a conventional pad-dry-cure laboratory-scale methodology. Following the coating process, fabrics were evaluated for flame retardant performance through the use of a vertical flame chamber. Fabrics were also evaluated for antimicrobial performance under varying light conditions (i.e. ultraviolet, visible, and no light) at Aerobiology Labs in Dulles, VA. Fabrics showing most flame resistant promise were further investigated for finish durability by flame retardant testing following a series of 5 washing and drying cycles. These laundered fabrics received further flame retardant evaluation in the flame chamber and also ICP elemental analysis comparing active ingredient concentrations on the fabrics pre and post-laundering. Results of this work show that without the addition of TiO2, THPC and urea were unsuccessful in imparting flame retardant properties on 80/20 polyester/cotton blended fabrics. However, flame retardant properties of both 100% cotton fabrics and 80/20 polyester/cotton fabrics are enhanced as add-on of titanium dioxide nanoparticles increase, specifically when using the silane cross-linker tetraethoxysilane (TEOS). Properties that were enhanced include char length as well as length of ignition. As on-weight-of-bath percentage of TiO2 increased to levels of 6% and above, all poly/cotton fabrics self-extinguished. Similar results were observed on 100% cotton fabrics. This, in fact, does show that TiO2 possesses synergistic effects with the phosphorus-based, condensed phase flame retardant, THPC + urea. Flame retardant performance levels following the laundering process were much more variable. In the case of the 100% cotton fabrics, some flame retardant property enhancements were noted, however poly/cotton fabrics showed no improvement over the control. Antimicrobial properties of un-treated poly/cotton fabrics were compared to fabrics treated with only THPC + Urea flame retardants and a combination of THPC + Urea + TiO2. Un-treated poly/cotton fabrics had no resistance to bacteria as each sample exhibited colony growth after 24 hours of incubation. THPC proved to be antimicrobially active against gram positive S. aureus under no light and active against gram negative K. pneumoniae under no light, visible light, and UV light. THPC + Urea + TiO2 proved to be antimicrobially active against both gram positive S. aureus and gram negative K. pneumoniae under no light, visible light, and UV light. This shows that both THPC + Urea and THPC + Urea + TiO2 have antimicrobial efficacy, however, the efficacy of THPC + Urea + TiO2 has higher overall efficacy than THPC + Urea as it is able to effectively eliminate both S. aureus and K. pneumoniae at all conditions. It is suggested that in future works, further attempts are needed to increase durability of flame retardant and antimicrobial coatings to the abrasive forces of laundering. Other cross-linkers, flame retardants, and application methodologies should be investigated.
Enhancing Electrostatic Properties and Hydroentangling Efficiency via Atmospheric Plasma Treatment
(2009-08-12) Malshe, Priyadarshini Prakash; Mohamed Bourham, Committee Co-Chair; Marian McCord, Committee Co-Chair; Peter Hauser, Committee Member; Hoon Joo Lee, Committee Member
ABSTRACT MALSHE, PRIYADARSHINI PRAKASH. Enhancing Electrostatic Properties and Hydroentangling Efficiency via Atmospheric Plasma Treatment. (Under the guidance of Professors Marian G. McCord and Mohamed A. Bourham) Keywords: Hydroentangling, atmospheric plasma, nonwoven Hydroentangling is the fastest growing nonwoven bonding technology. Known for the production of most textile-like nonwoven fabric, hydroentangling is a mechanical bonding technique which involves impingement of high velocity water jets onto a nonwoven fiber web. The mechanical action of needle-like water jets entangles fibers and consolidates the web into a fabric. The final properties of a hydroentangled web are reported to depend on the textile material and its intrinsic properties such as strength, modulus, bending rigidity and the fiber surface properties such as friction, fiber shape etc. Hydroentangling efficiency is also shown to depend on fiber to water interaction by way of hydraulic drag force. In previous works by other research groups, water pooling problem has been reported when hydroentangling hydrophobic fibers such as polypropylene. The focus of this work is to eliminate the problem via atmospheric plasma treatment prior to hydroentangling. The purpose of this study is to determine the effects of atmospheric plasma pre-treatment on nonwoven webs due to plasma induced hydrophilicity and other surface modifications such as roughness/smoothness. Different fiber substrates were treated with atmospheric plasma in a continuous run and hydroentangled at different times post-plasma treatment to determine the effect of aging on hydroentangling efficiency.
Novel Applications of Atmospheric Pressure Plasma on Textile Materials
(2009-11-16) Cornelius, Carrie Elizabeth; Richard Venditti, Committee Member; Mohamed Bourham, Committee Co-Chair; Peter Hauser, Committee Member; Marian McCord, Committee Chair; Ahmed El-Shafei, Committee Member
Various applications of atmospheric pressure plasma are investigated in conjunction with polymeric materials including paper, polypropylene non-woven fabric, and cotton. The effect of plasma on bulk and surface properties is examined by treating both cellulosic pulp and prefabricated paper with various plasma-gas compositions. After treatment, pulp is processed into paper and the properties are compared. The method of pulp preparation is found to be more significant than the plasma, but differences in density, strength, and surface roughness are apparent for the pulp vs. paper plasma treatments. The plasma is also used to remove sizes of PVA and starch from poly/cotton and cotton fabric respectively. In both cases plasma successfully removes a significant amount of size, but complete size removal is not achieved. Subsequent washes (PVA) or scouring (cotton) to remove the size are less successful than a control, suggesting the plasma is cross-linking the size that is not etched away. However, at short durations in cold water using an oxygen plasma, slightly more PVA is removed than with a control. For the starch sized samples, plasma and scouring are never as successful at removing starch as a conventional enzyme, but plasma improves dyeability without need for scouring. Plasma is also used to graft chemicals to the surface of polypropylene and cotton fabric. HTCC, an antimicrobial is grafted to polypropylene with successful grafting indicated by x-ray photoemission spectroscopy (XPS), dye tests, and Fourier transform infrared spectroscopy (FTIR). Antimicrobial activity of the grafted samples is also characterized. 3ATAC, a vinyl monomer is also grafted to polypropylene and to cotton. Additives including MohrÃ¢â‚¬â„¢s salt, potassium persulfate, and diacrylate are assessed to increase yield. Successful grafting of 3ATAC is confirmed by XPS and dye testing. A combination of all three additives is identified as optimum for maximizing graft yield.
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.
Synthesis, Characterization, and Evaluation of Novel Flame Retardant Monomers for Plasma-Induced Graft Polymerization.
(2010-07-07) Edwards, Brian; Ahmed El-Shafei, Committee Chair; Abdel-fattah Seyam, Committee Member; Peter Hauser, Committee Member