Volatile contaminant materials: relationship between condensate, effluent and bulk composition

Abstract

DC-93-500, SCV-2590 and SCV-2590-2 silicone/siloxane based co-polymers serve as adhesive components of satellites and other spacecraft. It is well known that out gassing of these materials is a major source of contamination. For the past several years we have been optically characterizing the condensates and their photofixed films via in-situ ellipsometry and quartz crystal microbalance (QCM) measurements. We have identified several common outgassed components in each of these materials via FTIR, including polydimethylsiloxane (PDMS), and Tetra-n-propylsilicate (NPS). We have studied the optical properties of the photofixed films produced at various wavelengths of incident light , as well as when mixtures of these films are employed as the outgassing source via variable angle spectroscopy ellipsometry. We can relate the photofixed material optical properties to the bulk liquids and to the films produced by the outgassssing of the actual co-polymers mentioned above. This work may lead to the evaluation of the optical properties of the photofixed effluents of actual adhesives by evaluating a few basic components