The Use of Principal Component Analysis to Classify PDMS Surfactants Used to Make Rigid Polyurethane Foams Based on Their Dynamic Surface Tension Characteristics

Polydimethylsiloxane surfactants are well known in the polyurethane industry. They play a vital role in the manufacture of both rigid and flexible foams. In order to achieve the phaseout of CFCs, as prescribed in the Montreal protocol, new blowing agents have been developed to make polyurethane foams. This has been accompanied by changes in the composition of the foam forming material including the silicone surfactants. This article describes a method for measuring the dynamic surface tension behavior of these silicone surfactants in model liquids representative of the polyol component in the foam forming mixture. The different dynamic surface tension characteristics of commercially available silicone surfactants are reported. In a second stage these data are analyzed using a chemometrics technique called principal component analysis. This allows the classification of the various surfactants in several subsets, each characterized by a specific dynamic surface tension behavior. The combined method of dynamic surface tension measurements and principal component analysis allows fast screening of surfactants used in the polyurethane industry.