This research evaluated the influence of concentration and surface tension (γ) of aqueous solutions of a non-ionic surfactant on the barrier effectiveness of a fabric containing microporous polypropylene (PP) film that may be used in pesticide protective clothing (PPC). Aqueous solutions of Triton® X-100, a non-ionic surfactant, at various concentrations were prepared, and the γ of each solution was determined. The immediate advancing contact angles (θ), made by a 5-<i>μ</i>L drop of each test liquid on the test fabric, were measured. Barrier effectiveness was evaluated from the capillary penetration, wicking, and wetting characteristics of the fabric using the surfactant solutions at various concentrations. Wetting characteristics were evaluated from the drop absorbency test, a modified Draves test, the spreading coefficient (S_c) values and, by inference, from a Zisman plot. As surfactant concentration increased, γ decreased, and then remained relatively steady past the 0.0134 percent concentration level, the critical micelle concentration (CMC) of Triton® X-100. As Triton® X-100 concentration increased, θ decreased, even past the CMC. Results of the study indicate that, as surfactant concentration increases, the amount of capillary penetration and the wicking distance increase even past the CMC. The time for drop absorbency and the Draves wetting tests were very high (> 600 seconds) for all liquids below CMC. Beyond the CMC, drop absorbency times were significantly lower for solutions of 2.0 and 5.0 percent concentration, and the Draves wetting times were also significantly lower. The values of the cos θ and the γ were used to calculate the S_c for each liquid. The calculated spreading coefficients indicate that the liquids at all concentrations did not spread (wet) on the micro-porous PP test fabric for the advancing θ measured within 10 seconds of placing the drop. Results of the statistical analysis showed that surfactant concentration was a significant factor in determining the barrier effectiveness of the fabric tested. Even though γ remained relatively unchanged beyond the CMC of the surfactant, the inability of the test fabric to serve as an effective barrier against liquid penetration by capillary action, wicking, and wetting increased significantly. Surface energy terms, that are normally used to explain liquid transport and wetting phenomena, may not in themselves be sufficient to determine the effectiveness of a fabric for PPC, especially since concentration of the surfactant, a pesticide adjuvant, is a significant factor in determining the barrier effectiveness of PPC. Consideration must be made for the fact that very high concentrations of surfactants are routinely used in pesticide application. / Master of Science

The purpose of this research was to investigate and compare the liquid transport properties of cotton nonwoven laminates of varying cotton/polypropylene fiber content (80:20, 60:40, 40:60, by weight) with a 100% polypropylene fabric and a 100% polyethylene fabric. Capillary, pressure and impact penetration mechanisms were investigated as well as other measures of fabric wetting, wicking, and liquid retention. A water/surfactant solution of surface tension close to that of the pesticide solution was used in some tests to determine whether it could be used to simulate liquid transport characteristics of the pesticide solution. The effect of volume on capillary and pressure penetration was also evaluated. Results indicated that the 100% polyethylene fabric offered the greatest resistance to all three penetration methods. The 80:20 cotton:polypropylene fabric, exhibited significantly greater amounts of penetration than the other fabrics in capillary penetration. There was no significant difference in the penetration values of the 100% polypropylene and the cotton laminates in the pressure penetration of the water/surfactant. There were no significant differences in the impact penetration values of the cotton laminates, but the 100% polypropylene exhibited significantly lower amounts of impact penetration than the cotton laminates. Pressure penetration was found to result in the most severe form of penetration. A high degree of correlation was obtained between penetration by the pesticide and penetration by the water/surfactant solution, whose surface tension was close to that of the pesticide solution. A higher retention of the pesticide resulted in lesser amounts of penetration of the pesticide solution. However, in the case of retention of water/surfactant, it was found that even though there were no significant differences in the retention values of the water/surfactant, there were significant differences in the penetration values of the water/surfactant. Surface tension of the solution was found to have an effect on the wetting and wicking responses of the fabrics, which affected the amount of capillary penetration. Increasing volume resulted in an increase in the amount of penetration that took place. / Master of Science

This study was conducted to explore the feasibility of using sleeves, along with both physiological and perceptual measurements, to assess the thermal comfort and heat strain in chemical protective clothing wear tests. The effect of body sites, i.e. the arms and the chest, and the effect of a Tyvek® coverall on skin temperature and sweat amount were investigated as well. Ten male subjects were selected from college students. Each subject was assigned to wear a garment of either T-shirt and pants or a changeable left-sleeved Tyvek® coverall with or without an experimental sleeve on the left arm. Three experimental sleeves were of the same style, but made of three different fabrics: Tyvek®, Pro/Shield I®, and Pro/Shield II®. Each subject wore an assigned garment and pedaled on a cycle ergometer in an environmentally-controlled room. Skin temperature, sweat amount, and subjective comfort evaluations were recorded and later analyzed by repeated-measures ANOVA. Results showed there is a feasibility in using a sleeve with a T-shirt/pants standard garment for assessing thermal comfort in chemical protective garment wear tests. The T-shirt/pants standard garment yielded more consistent and reliable results than did the Tyvek®-coverall standard garment. Under the same conditions, there were no significant differences in skin temperature and sweat amount among the left and right upper arms and the chest. The Tyvek® sleeve in this study impeded the transfer of heat by the greatest amount, followed by the Pro/Shield II® sleeve and the Pro/Shield I® sleeve, respectively. / Master of Science

The very nature of the fire fighting environment makes thermal degradation of turnout gear inevitable. Standards that are currently in place to ensure that new gear performs adequately for the protection of the fire fighter do not provide a quantitative measure for assessing this gear once it is in service. When the performance of the gear is compromised due to degradation, it could put the fire fighter wearing the gear at unnecessary risk. A non-destructive test that indicates the end of the useable service of the garment would be a benefit to the fire service. Full scale fire tests were conducted to suggest a range of heat fluxes that turnout gear specimens should be subjected to in order to simulate degradation caused by in-field use of the gear. A series of destructive tests were conducted on exposed specimens. A number of non-destructive tests were performed on the same specimens. The results of destructive and non-destructive tests were compared. This research explored some options for non-destructive tests of turnout gear. Digital image analysis and colorimetry were both offered as possibilities for a diagnostic test of this gear. Correlations between destructive performance tests and the colour changes of the outer shell fabric could be used to develop non-destructive tests to evaluate every garment owned by a department. More work is required to improve these test methods, but the door has been opened to better testing for in-use gear, and ultimately to provide better protection for the fire fighters who use this clothing.

The very nature of the fire fighting environment makes thermal degradation of turnout gear inevitable. Standards that are currently in place to ensure that new gear performs adequately for the protection of the fire fighter do not provide a quantitative measure for assessing this gear once it is in service. When the performance of the gear is compromised due to degradation, it could put the fire fighter wearing the gear at unnecessary risk. A non-destructive test that indicates the end of the useable service of the garment would be a benefit to the fire service. Full scale fire tests were conducted to suggest a range of heat fluxes that turnout gear specimens should be subjected to in order to simulate degradation caused by in-field use of the gear. A series of destructive tests were conducted on exposed specimens. A number of non-destructive tests were performed on the same specimens. The results of destructive and non-destructive tests were compared. This research explored some options for non-destructive tests of turnout gear. Digital image analysis and colorimetry were both offered as possibilities for a diagnostic test of this gear. Correlations between destructive performance tests and the colour changes of the outer shell fabric could be used to develop non-destructive tests to evaluate every garment owned by a department. More work is required to improve these test methods, but the door has been opened to better testing for in-use gear, and ultimately to provide better protection for the fire fighters who use this clothing.

Clothing can influence heat stress depending on the design and its ability to act as a barrier. The progressive heat stress protocol permitted the collection of data to empirically estimate the apparent total evaporative resistance (Re,T,a). Five different clothing ensembles were evaluated, which included work clothes, cotton coveralls, and three limited-use protective clothing ensembles including a pthesis-barrier ensemble, (Tyvek® 1424), water-barrier, vapor-permeable ensemble (NexGen® LS 417), and a vapor-barrier ensemble (Tychem QC®). The study design called for three metabolic level's: low, moderate, and high (L, M, & H) and three heat stages: compensable, transitional, uncompensable (C, T, U). The purpose of this study was to determine if Re,T,a values remained constant over a range of metabolic and heat stage levels. Calculated Re,T,a values were compared using a four-way mixed model analysis of variance. Significant differences for Re,T,a were found among ensembles, metabolic levels, heat stress stages, as well as interactions among ensembles and metabolic levels along with ensembles and heat stress stages (p < 0.0001). A Tukey's Honestly Significant Difference multiple comparison test identified where significant differences occurred (p < 0.05). Results show Re,T,a values differ over a range of metabolic levels and stages of heat stress. Additionally, convection is more supportive of evaporative cooling than diffusion.

Dissertation (Ph.D.)--University of South Florida, 2006. / Title from PDF of title page. Document formatted into pages; contains 107 pages. Includes vita. Includes bibliographical references.

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Made available in DSpace on 2014-10-09T12:48:28Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:28Z (GMT). No. of bitstreams: 1 09066.pdf: 3054181 bytes, checksum: 62e4252d9f76ef15308c15317e1fca18 (MD5) / Dissertacao (Mestrado profissionalizante em lasers em Odontologia) / IPEN/D-MPLO / Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo