Reduction of liquid terminated-carboxyl fluoroelastomers using NaBH(4)/SmCl(3)

Using a simple one-pot method, the reduction of liquid terminated-carboxyl fluoroelastomers (LTCFs) by sodium borohydride and samarium chloride (NaBH(4)/SmCl(3)) was successfully realized and liquid terminated-hydroxyl fluoroelastomers (LTHFs) were obtained. The structure and functional group content of LTCFs and LTHFs were analyzed by FTIR, (1)H-NMR, (19)F-NMR and chemical titration. The results showed that –C[double bond, length as m-dash]C– and carboxyl groups of LTCFs were reduced efficiently, the reduction rate reached 92% under optimum reaction conditions. Compared with other frequently-used metal chlorides, SmCl(3) with a high coordination number could increase the reduction activity of NaBH(4) more effectively and the reduction mechanism was explored.