The present invention relates to chain extenders, processes for their preparation and their use in the preparation of biocompatible biodegradable polyurethanes and polyurethane ureas for biomedical applications such as stents, scaffolds for tissue engineering. The chain extenders comprise a compound of formula (I) ##STR00001##

The invention relates to a process for preparing an alkoxylated product. The aim of the invention is to provide aromatic polyols for preparing polyurethane-based and polyisocyanurate-based polymers, which ensure good miscibility with the isocyanate component and other components, have a good storage stability and render the end product flameproof. For this purpose, the invention devises a process for preparing an alkoxylated product by. reacting bisphenol F with propylene carbonate and/or propylene oxide as propoxylation agent and ethylene carbonate and/or ethylene oxide as ethoxylation agent, the propoxylation agent and the ethoxylation agent being used in a molar ration of 70:30 to 45:55.

The invention relates to a process for preparing an alkoxylated product. The aim of the invention is to provide aromatic polyols for preparing polyurethane-based and polyisocyanurate-based polymers, which ensure good miscibility with the isocyanate component and other components, have a good storage stability and render the end product flameproof. For this purpose, the invention devises a process for preparing an alkoxylated product by reacting bisphenol F with propylene carbonate and/or propylene oxide as propoxylation agent and ethylene carbonate and/or ethylene oxide as ethoxylation agent, the propoxylation agent and the ethoxylation agent being used in a molar ration of 70:30 to 45:55.