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IR and ~(29)Si NMR were used to determine the structures of ladderlike polymer polyphenylsilsesquioxanes (PPS). It was found that PPS with lots of defects had a wide and strong absorption band in 1000—1400 cm~(-1) with only one sharp peak at 1137 cm~(-1) while two peaks (1130 and 1045 cm~(-1) were observed for PPS with perfect ladderlike structure. Branching and crosslinking of PPS lead to the reduction of 1045 cm~(-1) peak. ~(29)Si NMR spectra, however, showed two peaks (δ=-78 ppm and -87 ppm when δ_(HMDS)=0 ppm) for defective or branched PPS. The -87 ppm peak is related to the ladderlikely constructed Si atoms and -78 ppm corresponds to defective Si atoms. PPS with defects less than 0.1% chain units was obtained by azeotropic polycondensations.
IR and ~ (29) Si NMR were used to determine the structures of ladderlike polymer polyphenylsilsesquioxanes (PPS). It was found that PPS with lots of defects had a wide and strong absorption band in 1000-1400 cm -1 with only one sharp peak at 1137 cm -1 while both peaks (1130 and 1045 cm -1) were observed for PPS with perfect ladderlike structure. Branching and crosslinking of PPS lead to the reduction of 1045 cm -1 peak-29 NMR spectra, however, showed two peaks (δ = -78 ppm and -87 ppm when δ_ (HMDS) = 0 ppm) for defective or branched PPS. The -87 ppm peak is related to the ladder like constructed Si atoms and -78 ppm corresponds to defective Si atoms. PPS with defects less than 0.1% chain units was obtained by azeotropic polycondensations.