Hyperbranched polymers are by definition highly branched and polydisperse polymers. The synthesis of such materials has drawn much attention in recent years because of their properties being similar to those of dendrimers. The principal advantage of hyperbranched polymers compared to dendrimers is that they can be synthesised via a one step process. Among the different approaches employed to obtain hyperbranched polymers, free radical techniques are preferred due to the versatility the free radical process offers. For instance, such processes are tolerant of impurities, including water. The strategy followed by different groups involved the copolymerisation of a monofunctional vinyl monomer with only small amounts of a bifunc-. tional vinyl monomer; if higher amounts of bifunctional monomer were employed, only insoluble materials were obtained. In contrast, previous work in our group demonstrated that by using an enhanced controlled polymerisation method, the homopolymerisation of bifunctional vinyl monomers to obtain hyperbranched polymers could be achieved in high yield. This reported new strategy was found difficult to reproduce. Therefore, in Chapter 1 the background of the thesis is introduced followed by Methods (Chapter 2). In Chapter 3 the process development carried out to obtain an optimised system for the polymerisation of an 80% commercially available pure bifunctional monomer is presented. In Chapter 4, the characterisation and reproducibility of the synthesised materials is investigated. Finally in Chapter 5, 100 % pure bifunctional monomer is synthesised and polymerised using the best conditions from Chapter 4. In addition, a comparison between the polymerisation of 80% and 100% pure bifunctional monomer is presented.