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Ten poly(amide) oligomers were prepared from four acid dichlorides and two full-aromatic diamines, the latter containing silicon or germanium in their structure. The polymers, which contain Et/Me, Et/Et and nBu/nBu combinations on heteroatom of the acid dichloride moiety, were characterized by spectroscopic techniques, including  29 Si NMR. The yields obtained and the η ιnh  values established were low, indicating the low molecular weight nature of the polymers. Thermal stability was also evaluated by TG and DSC techniques. When a methyl group was replaced by a Et, the Tg of the poly(amides) (PAs) was increased in accordance with the gain in the flexibility of the chain. However and in general terms, the  PAs  with  n Bu groups show the inverse effect. Probably, the possibility of an effective interaction between these side chains affects negatively the flexibility of the main chain. On the other hand,  PAs  that contain single silicon in their structure show lower T g  values than the Ge-containing  PAs . For the other heteroatom combinations, similar results were obtained. This fact does not agree with the lower size of silicon atom which should increase the molecular rigidity and therefore their T g  values. Probably, the influence of the side groups is decisive in hindering the chain rotation. The thermal degradation temperature (TDT) changed in agreement with the packing factor of the chains which was depending on the size of substitute groups. So, when Et group was replaced by  n Bu as lateral group, lower TDT were recovered. With respect to the heteroatoms used in the main chain, the TDT values do not show a clear tendency.

Poly(amide) oligomers with silarylene and/or germarylene units – synthesis, characterization and thermal studies