Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R03-OH-008354, 2008 May; :1-19
Protective clothing is one of the most important personal protective equipment for emergency responders, who are facing increased occupational threats in their high risk jobs. However, currently used protective clothing has significant shortfalls, including the lack of multiplepurpose protective clothing, the unsatisfactory protective performance, and the tradeoff between protection and comfort. Some of these problems cannot be solved using current principles and technologies. Innovative approaches are needed to develop wearable multipurpose protective clothing to enhance the safety and health of emergency responders. The long term goal of this project is to develop novel wearable thermal, biological, and chemical protective clothing materials with enhanced comfort performance for emergency responders. To reach this goal, currently used thermal protective fabrics were chosen as the base material, and a coating technology was employed to coat reusable and rechargeable polymeric oxidizers onto the base fabrics through breathable flame-retardant coatings. The specific aims of the proposed research are to: (1) screen reusable and rechargeable polymeric oxidizers that can effectively decontaminate surrogates of biological and chemical warfare agents; (2) establish the optimal formulations and technologies to coat the selected polymeric oxidizers onto thermal protective fabrics through breathable flame-retardant coatings containing chemical absorbents; (3) evaluate the thermal protective, biological protective and chemical protective functions, the mechanical properties, as well as the comfort performance of the new fabrics; and (4) provide preliminary data for the determination of the cost-effectiveness of the new approach. In our studies, we first evaluated chloromelamines, N-halamines, nitroxyl radicals, photosensitizers and chromate salts as reusable oxidizers. We found that chloromelamines and amide-based N-halamines could effectively inactivate gram-negative bacteria, gram-positive bacteria, fungi, and viruses in less than 5 min, and spores in less than 3 h. Both of them could also oxidize different chemicals including CES. Other oxidizers showed little effect on spores. Therefore, we decided to use chloromelamines and amide-based N-halamines as the oxidizers for the next step. Upon the successful completion of the first step, we studied how to incorporate the oxidizers into different fabrics. For chloromelamines, we synthesized a novel compound, ACHT, which could be directly covalently bound onto fabrics materials. The treated fabrics inactivated multi-drug resistant E. coli and S. aureus in less than 1 min. For amide-based N-halamines, we successfully grafted MAA onto different fabric materials including Nomex and Kevlar. To select coating formulations, we evaluated 5 commercially available textile coatings, and we have successfully formulated the coating formulations which bound tightly to Nomex and Kevlar, and the coatings were durable for 50 washes. We found that the treated textiles inactivated 1,000,000 spores/mL of B. subtilis spores in less than 2 h. The spore-killing functions were stable for more than 12 months, and most importantly, once it was lost, it could be easily recharged by washing in the presence of chlorine bleach. The recharge process could be repeated for more than 20 times. We also found that the treated fabrics decomposed 85% of CES in 30 min, and that the fire-resistant performances of the Nomex and Kevlar fabrics were not affected. Nevertheless, after treatment, although the tearing strength was increased to around 2 times higher, the abrasion resistance decreased because the fabrics become more rigid than before. These results successfully demonstrated the concept that wearable multi-purpose protective clothing can be developed to provide thermal, biological, and chemical protective activities simultaneously. These findings will serve as an important base for the continuation and expansion of the project to utilize the new technology in real applications to significantly enhance the occupational safety and health of emergency responders. Based on these results, an RO1 application, Multi-Protective Clothing For Emergency Responders will be submitted to NIOSH to continue and expend the studies to achieve this long-term goal.
Yuyu Sun, Biomedical Engineering Program, University of South Dakota, 2329 N Career Ave., Suite 207, Sioux Falls, SD 57107