Synthesis of phosphorous-containing polymers by ATRP and SET-LRP

• Main Author: Fidge, Christopher
• Published: University of Warwick 2009
• Subjects: 541.2254; QD Chemistry
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.524228

The aim of this work was to synthesise phosphorous-containing polymers with controlled molecular weights and low PDIs. Phosphorus functionality was introduced both by polymerising a phosphorus-containing monomer and by the reaction of functional polymers with phosphorous compounds in a postpolymerisation approach. Cu(0)-mediated SET-LRP was studied to ascertain if it could be used for the polymerisation of ethylene glycol containing monomers. When using copper wire as the source of metal, significant periods of inactivity or ‘induction’ time were observed at the beginning of the polymerisation. By altering the polymerisation temperature and the surface area of the copper, their affect on the ‘induction’ time was studied. SET-LRP was used to polymerise DEGMEMA, PEGA454, PEGMA475 and PEGMA1100, serving as model compounds for subsequent polymerisations of phosphorus-containing monomers. ATRP and SET-LRP were used to synthesise homopolymers of DEMOEP and copolymers of DEMOEP with both DEGMEMA and PEGMA475. ATRP resulted in well defined polymers with low PDIs, but SET-LRP of DEMOEP and DEMOEP/DEGMEMA exhibited high termination and high PDIs. By replacing DEGMEMA with PEGMA475, polymer synthesis by SET-LRP was much improved; termination was low, molecular weight growth was linear with respect to conversion and the final polymers had narrow molecular weight distributions. The control of these polymers by SET-LRP equalled those of ATRP. Deprotection chemistry was used to attempt the removal of the ethyl groups of the pendant phosphate groups in DEMOEP-containing polymers. Three different systems were used and their affect on the polymers was studied. Using a post-polymerisation modification strategy, reactive succinimidyl-ester containing polymers were modified with the amino-functional phosphate, AMPA. In a similar fashion, the reaction of P-H bonds residues with amines and aldehydes was also studied for the modification of reactive polymers. These ‘Kabachnik-Fields’ reactions were performed on small molecule model amines, commercially available amino-functional polymers and finally, a water-soluble succinimidyl-ester containing copolymer synthesised by ATRP.