ly fluorine, chlorine and bromine, [0027] a linear or branched alkyl group comprising 1 to 12 carbon atoms, [0028] a linear or branched alkoxy group comprising 1 to 12 carbon atoms, [0029] a haloalkyl or haloalkoxy group corresponding to the (C1-C12) alkyl or alkoxy groups above respectively which are substituted with at least one halogen atom, and notably a fluoroalkyl group of this type, [0030]