Summary: Radical homopolymerizations and copolymerizations of styrene were performed in toluene and N,N‐dimethylformamide (DMF) as solvents using different initiators with and without microwave irradiation. Only the homopolymerization of styrene under microwave irradiation in DMF with DtBP showed significantly enhanced styrene conversion whereas other initiators resulted in no or only slight increase of styrene conversion under microwave irradiation. In any case, DMF was required to gain in styrene conversion under microwave irradiation. Significantly higher monomer conversions were observed under otherwise comparable conditions in the copolymerization of styrene and methyl methacrylate (MMA) in DMF. Microwave‐induced selectivity of monomers was not observed in copolymerizations.Yield of styrene polymerizations under varying reaction conditions initiated by DtBP.imageYield of styrene polymerizations under varying reaction conditions initiated by DtBP.
The influence of elastic light scattering on the Raman signal of polymer latexes was investigated by varying the sample position relative to the confocal Raman probe. Measurements on polystyrene latexes revealed that the absolute Raman signal is very sensitive to the alignment of the sample. Furthermore, it was shown that for particle sizes below 140 nm and solid weight contents below 20%, changes in the absolute Raman signal can be described fairly well by turbidity laws. For larger particle sizes and higher solid weight contents deviations occur, but a correlation between these variables and the Raman signal still exists. In contrast, the normalized intensities are not influenced by varying the sample alignment in measurements on polymer latexes when using an excitation laser source at 532 nm. The important consequence of this is that the determination of chemical composition is not influenced by the elastic light scattering effects.
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