RECOMMENDATIONS AND FUTURE RESEARCH

The investigations presented in this thesis have revealed that the MWD method is certainly a method with great potential for studying the chain-length dependence of termination reactions. However, the leap from the theoretical study presented in chapter 3 to the experimental one presented in chapter 4, introduces two additional complications (i) the correct shape of the number MWD must be determined and (ii) this number MWD must be scaled correctly. 

To increase the accuracy of the scaling of the number MWD, there seem to be two experimental techniques (or routes) that might prove to be useful. First of all, a combination of time-resolved single-pulse pulsed-laser polymerization with subsequent analysis of the MWD of the formed polymer product can be employed. From the time-resolved trace, accurate data on the radical concentration versus time can be deduced, which can then be used in the scaling of the number MWD. An alternative method to improve the scaling accuracy might arise form the use of mass-spectrometry techniques. Polymeric material with 

In the kinetic analysis, the fact that termination and chain transfer are second and first order processes with respect to the radical concentration, respectively, can then be exploited. The scaling of the number MWD now has to be done such that the radical concentration versus time that is derived from this distribution, is in agreement with the amount of material that is found to originate from chain transfer to monomer. Hence, the degree of freedom in the scaling of the number MWD is limited by a second kinetic condition. It should be noted, however, that knowledge of the ratio of termination by combination over disproportionation is needed for that. 

Furthermore, the MWD method should certainly be applied to study the effects of solvent quality upon the chain-length dependence of kt. As the solvent quality has a profound effect on the dimensions of polymer coils in solution, a change in this quality will reveal 

In conclusion it can be said that the MWD method is capable of determining the chain-length dependence of kt model-independently. This method has been validated theoretically and, as long as the number MWD can be determined and scaled correctly, the method is robust and reliable. In this thesis, the first model-independent results have been reported for a set of three acrylates. These results will enable a better description of the overall kinetics of free-radical polymerizations and better predictions of the resulting MWDs and polymer properties. It is sincerely hoped that this method and lines of thought presented will find continuation in future scientific work by others in this field of great scientific interest and practical importance. 

---