Tailored alendronate-based copolymers for efficient complexation of neodymium, surrogate of actinide

• Well-defined P(OEGMA x - co -MAA y-z - co -AleMAAm z ) MW were synthesized. • Alendronate-based copolymers were able to efficiently complex neodymium (III) cations. • Sorption capacities are of great interest compared to materials already described in the literature. Bisphosphonate-functionalized copolymers were prepared through a two-step synthetic procedure to develop materials with enhanced metal coordination capabilities. Initially, poly(oligo(ethylene glycol) methyl ether methacrylate- co -methacrylic acid) (P(OEGMA- co -MAA)) copolymers were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. By varying the molecular weight (20000 or 60000 g.mol −1 ) and OEGMA/MAA molar ratio, a range of copolymers was obtained with controlled molecular characteristics. Optimal RAFT conditions, using a [AIBN]/[CTA] molar ratio of 0.5/1, enabled high monomer conversion rates while maintaining narrow dispersity. The random incorporation of monomers was confirmed by kinetic studies and the determination of reactivity ratio. In the second step, bisphosphonate functionalities were introduced by achieving EDC/NHS coupling reaction in the presence of alendronate sodium to afford P(OEGMA- co -MAA- co -AleMAAm) copolymers. The successful functionalization was confirmed by 1 H and 31 P NMR spectroscopy. Finally, complexation properties toward neodymium (III) cations, surrogates of actinides, were determined as a function of OEGMA/MAA molar ratio, alendronate functionalization rate, and copolymer molecular weight. Best neodymium (III) sorption dealt with the complexation of 47.3 mg of Nd(III) ions per gram of P(OEGMA 25 - co -MAA 65 - co -AleMAAm 10 ) 60k copolymer. This result is of great interest, as it shows that optimized synthesized materials are more efficient than most of the materials reported to date in the literature for the complexation of Nd(III) cations, thus opening the way to their use for application in actinide decontamination.