Preparation, Curing and Properties of Liquid Amine-Terminated Fluoroelastomers

A two-step nucleophilic substitution mechanism was used and described to prepare liquid amine-terminated fluoroelastomers (LTAFs) by using liquid hydroxy-terminated fluoroelastomers (LTHFs) as raw materials, benzenesulfonyl chloride as an activator, and hexanediamine as an amine source. A reaction time of 24 h at 18°C and a molar ratio of groups –NH₂/–OH = 6.00 is an optimal condition for obtaining LTAFs with a yield of amino groups of 51%. The resulting LTAFs has a higher viscosity and lower thermal stability than LTHFs, while the molecular weight and distribution, as well as the glass transition temperature, remain essentially similar. Aziridine cured LTAFs has the best comprehensive mechanical properties and excellent chemical solvent resistance.