Browsing by Author "Dr. Juan P. Hinestroza, Committee Chair"

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    Performance Evaluation of Chemical Protective Clothing Materials under Dynamic Mechanical Deformation
    (2005-07-13) Shiels, Brian Patrick; Dr. Juan P. Hinestroza, Committee Chair; Dr. Roger L. Barker, Committee Co-Chair; Dr. Morteza G. Khaledi, Committee Member; Dr. Orlando J. Rojas, Committee Member
    This thesis presents a comprehensive assessment of testing methodologies currently used for evaluating the performance of protective clothing materials. Special emphasis is placed on highlighting the inadequacy of such test methods and their lack of correlation with real life scenarios which may introduce mechanical deformation. ASTM F23 standardized rubber sheets were used to evaluate the sorption, permeation and penetration behavior of the samples when exposed to a standardized liquid challenging agent. 2-Chloro-1,3-butadiene (neoprene) was used as the standard chemical protective clothing material and liquid acetone was selected as the standard challenging agent. The dynamic mechanical properties of the samples were assessed via creep and stress relaxation testing techniques using customized submersion clamps. Quantitative agreement between sorption and permeation experimental data validated the concept that diffusion was the rate-limiting step for the transport of acetone through neoprene rubber. Creep and stress relaxation experiments illustrated a strong time dependency of the storage and loss modulus of the neoprene samples when exposed to the challenging agent. The Young's modulus of the standard material was also found to be a decreasing function of the number of loading-unloading cycles highlighting the effect of mechanical deformation of the barrier properties of protective clothing materials. Potential improvements to existing testing methodologies are proposed and discussed in detail.