The real time bulk polymerisation of 2-hydroxyethyl methacrylate (HEMA) and 2-ethoxyethyl methacrylate (EEMA) initiated with benzoyl peroxide has been studied over a range of initiator concentrations and polymerisation temperatures with the purpose of evaluating the kinetic rate parameters for polymerisation across the entire range of conversion. Conversion-time data were obtained using FTIR spectroscopy to monitor the instantaneous monomer concentration while the propagating radical concentration was determined using ESR spectroscopy. For the polymerisation of HEMA at 333 K initiated with 0.0125 M BPO kp= 1200 M-1s-1 and kt = 1.1 x 106M-1s-1 at 10% conversion. All values of kp at low conversion are considerably higher than for MMA and can be explained in terms of the alignment of monomer molecules through the hydrogen bonding of the hydroxyl group on the side chain of the monomer. A lower kt compared to MMA, at low conversion, is the result of the high viscosity of the system which is again the consequence of the hydroxyl group. The early commencement of the Trommsdorff region is simply the result of the alignment of monomer which contributes to the high viscosity of the system. At high conversion, in the glassy state, both kp and kt drop significantly i.e. kp= 60 M-1s-1 and kt = 4 M-1s-1 at 96% conversion. The effect of a different type of initiator on the polymerisation of HEMA was investigated. A lower maximum radical concentration for the bulk polymerisation of HEMA initiated with AIBN was observed. However, the changes in conversion were in accordance with the rate of decomposition of both initiators. For the polymerisation of EEMA the propagating rate coefficient, kp, remained constant throughout the entire range of conversion because the glass transition temperature of the formed polymer is lower than the polymerisation temperature. Hence, the system does not become glassy and so kp does not decrease. The profile of kt was very similar to that of MMA up to the glass region, that is it remained high and constant during the pregel region up to the commencement of the Trommsdorff where it drops marginally and again remains constant to 100% conversion. The effect of different initiators on the polymerisation of EEMA was also studied and it was found that the results for BPO and AIBN are very similar. The γ-radiolysis of these two polymers has been studied using ESR, NMR, GC and DSC techniques. PHEMA : Gamma Irradiation at room temperature resulted in crosslinking of the system and a lower G(R•) was obtained, compared to irradiation at 77 K. The following gaseous products were identified using GC: CH4, CO and CO2 with G-values of 0.24, 0.51 and 0.64, respectively. These gaseous products and other low molecular weight products such as ethanol, acetaldehyde, hydroxyethyl formate and isopropyl formate (minor), which were identified by NMR spectroscopy, are the result of side chain scission of the polymer during the irradiation. A combination of the nine line and the two line ESR spectra at room temperature indicates that main chain scission has occurred (9-line) and that the - • CH- is a very stable species which indicates the system is very rigid. Main chain scission resulted in new chain ends as determined by NMR. Although the polymer undergoes scission, it also crosslinks with the ratio of G(S)/G(X) = 2 above the gelation dose, Dg, of 150 kGy. PEEMA: At 77 K the G(R•) for this polymer was very similar to MMA and PHEMA. The major gaseous products are CO, CO2, C2H4, C2H6 and a very small amount of CH4 with G-values of 0.85, 0.89, 0.15, 0.29 and 0.06, respectively. As the polymer undergoes increased crosslinking, less methane is produced. These gaseous products and other low molecular weight products such as ethanol, ethoxyethanol, tetrahydrofuran and ethoxyethyl formate which were determined by NMR spectroscopy are the result of side chain scission. Monomer is one of the low molecular weight products detected at low doses as the result of depropagation of the polymer since the irradiation temperature is above its glass transition temperature. However, at higher doses, the polymer undergoes crosslinking and hence the monomer was not identified as a low molecular weight product. Main chain scission also occurs leading to the 9-line ESR spectrum of the propagating radical and new chain ends as identified using NMR. The high stability of -•CH- at higher temperature again indicates that the system is very rigid as the result of crosslinking. Crosslinking of the polymer occurs through the radical site of macromolecules along the side chain with the ratio of G(S)/G(X) = 1.5 above the Dg which is about 50 kGy.