The utilization of MS and MS/MS techniques have resulted in the complete characterization of chain-end, in-chain and cyclic polystyrene and polybutadiene as well as an analytical method which allows the rapid determination of the location of functionality as well as determining if the material is linear or cyclic.
The characterization of in-chain polystyrene is described and compared to chain-end polymers comprised with similar functionality. This allowed the differentiation of fragment ions resulting from the CAD fragmentation between the two types of functionalization. Additionally, the MS/MS spectra of in-chain functional polymers allow the determination of average chain length on either side of the functional group.
Further expansion of polystyrene understanding was accomplished by characterizing macrocycle polystyrene which also contained a functional group. The CAD spectrum provided conclusive proof that the material was in fact cyclic due to the observed monomer losses as a result of CAD induced ring opening. After ring opening the macrocycle behaves similarly to an in-chain functional polymer and produces a mid- mass range Poisson distribution corresponding to the chain length on each side of the functional group, however, in this case it does not directly correlate to average chain length. This cyclic fragmentation pattern was confirmed when cyclic non-functionalized polybutadiene was characterized. Here the mid-range Poisson distribution was absent due to no functionality being present. However, the same monomer loss was observed which further confirmed that the monomer loss was indeed a function of the ring opening rather than a spectral feature induced by the ToF/ToF mechanism being akin to PSD. This was further confirmed by using a Q/ToF to verify the monomer loss after ring opening.
Characterization of polybutadiene without pyrolysis was also conducted. While the adherence to free radical degradation was maintained it was discovered that unlike polystyrene, polybutadiene preferentially fragments by internal rearrangements.
Finally, by comparing the different MS/MS fragmentation patterns of the various materials utilized for this work the ability to determine where the functional group is and whether or not the material is cyclic and further if the macrocycle contains functionalization is possible by simply observing the MS/MS fragmentation pattern.