ROMP-processing of mono- and di-functional imidonorbornene derivatives
The work described in the thesis is concerned with making new polymeric materials via ring opening metathesis polymerisation (ROMP) using a well-defined ruthenium carbene as an initiator. The object of the study was to provide a process for producing shaped articles by introducing a reactive liquid mixture into a mould in which the reacting liquid mixture undergoes ROMP in the bulk to produce the moulded article. Mono- and difunctional imidonorbomene derivatives were used as monomer and crosslinker respectively. The properties of the cured samples were determined by sol-gel analysis, DSC, TGA, nmr and IR spectrometry. Gel fraction, Tg and content of unreacted monomer were used to characterise the cured samples. The results indicated a strong dependence of the polymers appearance and properties on the polymerization formulation and protocol, i.e. the monomer, the crosslinker and the polymerization conditions. The relative reactivity of the exo- and endo-monomers was investigated using the 'Hnmr technique since the initiation and propagation steps of the polymerisations can be followed in detail by this technique. The results showed that the polymerisations are living and the exo-isomer is more reactive than endo-isomer. A wider range of polymers can be prepared from solution polymerisation as compared to bulk polymerisation. The polymers derived from solid monomers, the monofunctional monomer with short N-alkyl pendant groups and all the difunctional monomers, could be prepared more easily in solution than in bulk polymerisation. The endo-monomer and the monofunctional monomer with long N-alkyl pendant group showed very low reactivity and were not suitable for ROMP in bulk but underwent solution polymerisation. It was found that the thermal properties of the linear polymers depend upon the amount of each monomer isomer incorporated into the polymer chain and the ength of the N-alkyl pendant groups. All linear polymers are soluble in chlorinated solvents from which clear films can be cast. The work described establishes conditions for production of fully crosslinked solids with only traces of the sol fraction.