Simple Hand Casting Procedure

TDI polyether prepolymers such as the Adiprene LlOO series are viscous liquids at room temperature with a slight isocyanate odour. They are stable at room temperature in the absence of moisture but at elevated temperatures, even when moisture-free, they have only a limited life. A brief description of these prepolymers is given in Table 5.1. 

Chemical composition Fully saturated urethane prepolymer  

Odour Slight isocyanate Slight isocyanate Slight isocyanate None Faint 

Storage stability Excellent at room temperature in the absence of moisture  

Solubility Soluble in aromatic hydrocarbons, ketones esters, and chlorinated hydrocarbons  

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Since flat membranes are relatively simple to prepare, they are very useful for testing on a laboratory scale. For very small membrane surface areas (less than 1000 cm ), the membranes are cast mostly by hand or semi-automadcally, not on a non-woven polyester but often on a glass plate (other materials can also be used, e. g. metals, and polymers such as polytetrafluoroethylene, polymethylmethacrylate etc.). The same procedure is followed as that depicted in figure HI - 5. 

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