near alkyl, branched alkyl or cyclic alkyl having 1 to 10 carbon atoms, or simple or substituted aryl having 1 to 10 carbon atoms or heterocyclic, and R12 can in addition be H, R13 and R14 are same or different and represent H or linear alkyl, branched alkyl or cyclic alkyl having 1 to 10 carbon atoms, or aryl, 1 is 0 or an integer from 1 to 10, m is an integer of 1 to 10, and n is 2 to 1000. 41.