Synthesis and Solution Behavior of a Novel Polymer of Phosphorus Containing.

Abstract

Phosphorus-based polymers have found applications such as adhesion promoters for paints and adhesives,1 and complexing agents to recover metal ions from the environment and industrial liquids.2 One of the methods of incorporating phosphorus functionality into polymers is the polymerization or copolymerization of phosphorus containing vinyl monomers such as vinyl and allyl phosphonates.3 Polymers with phosphorus in the backbone are usually synthesized by either polycondensation or ring-opening methods.4 Reversible Addition Fragmentation Transfer (RAFT) is one of the most robust controlled/living radical polymerization techniques and allows for the controlled polymerization of such phosphonate-based monomers.5

In this study, a novel block copolymer poly(2-N-morpholinoethyl methacrylate)-b-poly(2-methacryloyloxy ethyl phosphate) (PMEMA-b-PMMEP) was synthesized via RAFT in water using PMEMA-CTA as macro raft agent. MMEP monomer was synthesized with 2-hydroxyethyl methacrylate (HEMA) and triethylamine at 0 oC and under nitrogen. PMEMA-CTA and PMMEP-CTA were synthesized in DMF using cyanoisopropyl dithiobenzoate (CIDB) as chain transfer agent. Polymers were characterized by using GPC and 1HNMR. The pH titration of PMMEP enabled determination of the dissociation constant of the phosphonic diacid group. Titration permitted us to determine that pKa1 and pKa2 were equal to 2.5 and 7.1, respectively. PMEMA-b-PMMEP block copolymer isoelectric point was found to be 5.8 by zeta potentiometer.

PMEMA-b-PMMEP block copolymer formed micelles by the addition of Na2SO4 or at elevated temperature in the basic aqueous solution via formation of the micellar core with MEMA. Characterization of micelles was performed by DLS and TEM.