Utilising anionic branched polymerisation techniques for the synthesis of novel nanoparticles



Alhilfi, Tamara
Utilising anionic branched polymerisation techniques for the synthesis of novel nanoparticles. [Unspecified]

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Abstract

Anionic polymerisation techniques have been optimised to develop a “one-pot”, facile method to produce both linear and branched polystyrenes utilising the “Strathclyde” route to highly branched structures. ATRP was investigated as a possible method but anionic polymerisation was found to give much better control over the size and structure of polystyrenes produced. Using this anionic polymerisation relatively monodisperse linear polystyrenes were synthesised with dispersity values as low as 1.03 for a polystyrene chain with a targeted degree of polymerisation (DPn) of 100 monomer units. A number of different structures of branched polystyrene were synthesised, and their different physical properties examined by viscometry measurements and differential calorimetry scanning experiments. It has been found that very dense, highly branched materials (with approximations of 48 polymer chains branched together) can be synthesised with a targeted primary chain DPn = 10 monomer units. Weight average molecular weight (Mw) values as high as 992,000 gmol-1 for branched polystyrene can be synthesised with a primary chain length of DPn =50 monomer units. Functional polystyrenes were synthesised both by initiation with an amine containing compound and sec-BuLi, resulting in chain end functionalisation, and also post-functionalised by sulphonation of synthesised polystyrenes, resulting in a statistical distribution along the polymer chains pendant groups. The hydrophilicity could be manipulated by the percentage of sulphonation. At over 30% sulphonation of the pendant polystyrene groups, the polymers become water soluble. Polymer nanoparticles have been synthesised by a nanoprecipitation method from functionalised branched polystyrene synthesised by anionic polymerisation techniques. Nanoparticles synthesised from DPn10 branched sulphonated polystyrenes were analysed by dynamic light scattering and found to be approximately 60nm with dispersity values as low as 0.15. They were found to be stable after 6 months ambienmt storage, and some preliminary testing on the encapsulation of Oil red suggests that the nanoparticles may be capable of encapsulating hydrophobic drugs.

Item Type: Unspecified
Additional Information: Date: 2014-02 (completed)
Subjects: Q Science > QD Chemistry
Divisions: ?? dep_chem ??
Depositing User: Symplectic Admin
Date Deposited: 05 Aug 2014 09:35
Last Modified: 29 Sep 2020 08:12
URI: http://livrepository.liverpool.ac.uk/id/eprint/16757