Replacement Non-Toxic Sealants for Standard Chromated Sealants

摘要

Strategic Environmental Research and Development Program (SERDP) 1075, entitled 'Replacement Non-Toxic Sealants for Standard Chromated Sealants' was funded by SERDP and carried out from 1999- 2004. The goal of this program was to develop environmentally compatible, non-chromated, drop-in replacement sealants for military use. In addition to chrome elimination, the volatile organic content (VOC) of the sealants was significantly reduced. These environmental goals are further enhanced by rapid cure times and longer shelf life. A seven step program was carried out by a team of experts from the Air Force Research Laboratory (AFRL), Naval Air Warfare Center (NAWC), Army Research Laboratory (ARL), Environmental Protection Agency (EPA), Department of Energy (DOE), University of Dayton Research Laboratory (UDRl), and Products Research Corp. (PRC). AFRL was the principle investigator; PRC formulated the sealants; UDRl, NAWC and ARL tested the formulations; EPA provided engineering expertise on low VOC solvents and DOE provided technical support. A new rapid curing polythioether polymer was used as base. Several epoxy and urethane curing agents were tried and combinations of non-chrome salts were investigated. After a number of prototype formulations were developed and tested, the best formulation was tested and qualified to both military and industry standards. The final phase of the program developed other classes of sealants for a wide range of uses. The end result of the program is several full qualified and ready for market sealants that eliminate the use of hexavalent chrome, reduce VOCs, increase shelf-life and cure more rapidly than the current sealants.