SBIR-STTR Award

Metal deposition and coating processes developed at Versar Inc., Make it possible to modify commercially available reticulated foam materials so that they will be more conductive without degrading other properties unacceptably. Thereby the problem of electrostatic charge buildup during aircraft refueling operations can be alleviated and the risk of fires reduced. Two parallel approaches are suggested: metal coating the foam structure and metal impregnating the foam polymer mass. Either should achieve the objective of reduced resistance and good physical properties in the treated foam. We propose to investigate a number of combinations of metals and processes involving cobalt nickel, copper, silver gold and palladium. From these will be selected the best in terms of attained conductivity, processing ease, and freedom from materials problems. The best process(ES) will be used to produce specimens that will be evaluated under mil-b-83054 to show that feasibility has been attained in physical properties as well as conductivity. A working relationship already exists between VERSAR and AFWAL (mlbt) from joint evaluations of other materials.

In a Phase I program to develop a conductive form of polyether polyurethane reticulated foam, coating foam with a small amount of nickel was found to impart electrical conductivity to the foam without degrading the physical properties. The process used is a form of chemical vapor deposition that is carried out at an unusually low temperature, accounting for the undergraded state of the coated foam. The conductivity was retained after severe flexing of the foam while immersed in kerosene, and no adverse reactions were found between the coated foam and kerosene or aluminum alloy. The proposed Phase II program will address the task of coating full size reticulated foam buns, 44 inches x 110 inches x 8 inches. The first stage will be to develop coating reactor data on buns of full cross section and subscale length. A full size reactor will then be designed and built to carry out the process uniformly and efficiently so that a set of coated foam buns can be furnished to the air force for evaluation in use. A parallel effort to develop a process to impregnate foam with metal will be carried out using different raw materials than in Phase I. The purpose is to make available a simpler process that can be appropriate for future reticulated foams of higher temperature polymers that may need less conductivity modification than polyether polyurethane.