1. These are substances having the inherent property of expanding by chemical transformation into thermally insulative heat- and fire-resistant foams or sponges upon exposure to heat above some critical temperature. Unpublished exploratory work on such materials has been carried out at Armstrong Cork Company.
2. Ueber Verbindungen des Formaldehydes mit mehrwerthigen Alkoholen (Mannit etc)
3. b Idem., Ann. Chem., 289, 20 (1898).
4. CCXIX.—The condensation of pentaerythritol with aldehydes
5. J. Janku, Z. Cervanka and S. Duras, Czechloslovakian Patent 107,978 (1963);