The Use of Principal Component Analysis to Classify PDMS Surfactants Used to Make Rigid Polyurethane Foams Based on Their Dynamic Surface Tension Characteristics
✍ Scribed by G. Biesmans; L. Colman; R. Vandensande
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 154 KB
- Volume
- 199
- Category
- Article
- ISSN
- 0021-9797
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✦ Synopsis
Usually the polyol stream contains the necessary additives Polydimethylsiloxane surfactants are well known in the polyureto achieve the final end properties and to aid the processing; thane industry. They play a vital role in the manufacture of both among these additives are the blowing agents, catalysts, and rigid and flexible foams. In order to achieve the phaseout of CFCs, surfactants. Polydimethylsiloxane based surfactants are as prescribed in the Montreal protocol, new blowing agents have known for their surface tension lowering effect on the polyol been developed to make polyurethane foams. This has been accomcomponent (1). These surfactants play a crucial role in facilpanied by changes in the composition of the foam forming material itating mixing of the two liquid streams, in helping with the including the silicone surfactants. This article describes a method nucleation, and in stabilizing the foaming mixtures. As such for measuring the dynamic surface tension behavior of these silicone surfactants in model liquids representative of the polyol com-the surfactants determine to a great extent the technical perponent in the foam forming mixture. The different dynamic surformance of the final foam. face tension characteristics of commercially available silicone sur-In view of the CFC phaseout new blowing agents were factants are reported. In a second stage these data are analyzed developed to make rigid polyurethane foams for insulation using a chemometrics technique called principal component analypurposes (2, 3). As such the more polar CFC 11 (trichlorosis. This allows the classification of the various surfactants in sevfluoromethane) was replaced with less polar molecules like eral subsets, each characterized by a specific dynamic surface ten-HCFC 141b (dichlorofluoro ethane) or even hydrocarbons sion behavior. The combined method of dynamic surface tension like n-pentane. These changes in blowing agent were accommeasurements and principal component analysis allows fast panied by the necessary changes in the polyol and isocyanate screening of surfactants used in the polyurethane industry. ᭧ 1998 streams to accommodate the changes in blowing agent polar-Academic Press