Poly(amides) and poly(imides) containing silicon and germanium in the main chain: Synthesis, characterization and thermal studies

Abstract

Poly(amides) and poly(imides) containing the heteroatoms Si or Ge in the main chain and bonded to four carbon atoms were synthesized and characterized by IR and 1 H, 13 C and 29 Si NMR. The acid dichlorides bis(4-chloroformylphenyl)-dimethylgermane, bis(4-chloroformylphenyl)-diphenylgermane, bis(4-chloroformylphenyl)-dimethylsilane, and bis(4-chloroformylphenyl)-diphenylsilane were synthesized from the ditolyl derivatives, which were oxidized to the respective diacids. The dianhydrides bis(3,4-dicarboxyphenyl)-dimethylgermane dianhydride, bis(3,4-dicarboxyphenyl)-diphenylgermane dianhydride, bis(3,4-dicarboxyphenyl)-dimethylsilane dianhydride, and bis(3,4-dicarboxyphenyl)-diphenylsilane dianhydride were synthesized from the dixylyl derivatives, which were oxidized to the tetraacids. Fully aromatic diamines also containing Si or Ge were synthesized from 4-bromo-N,N-bis(trimethylsilyl)-aniline and diphenyl-dichlorosilane or germane. The ditolyl and dixylyl derivatives were synthesized from 4-bromo-toluene or 4-bromo-xylene and dimethyl-or diphenyl-dichlorogermane, dimethyl-or diphenyl-dichlorosilane. The glass transition temperatures and the thermal stability were determined showing in general that the polymers with Si atom in the main chain presented higher values of both parameters due to the higher ionic character of the CÀ ÀSi bond compared with the CÀ ÀGe one, and due to the lower size of the Si atom that presents lower rotational barriers.

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

“…Probably, the packing factor of the chains is affected by the volume of the side groups. Similar results were obtained when we compared methyl of phenyl groups, with those poly(amides) with phenyl groups showing a higher TDT value [15].…”

“…Also we have described many kinds of condensation polymers containing Si and/or Ge in the main chain, bonded to side groups such as phenyl, methyl and other aliphatic groups, such as poly(carbonates), poly(thiocarbonates), poly(amides), poly(imides), poly(esters), and poly(urethanes) containing one or both heteroatoms [8][9][10][11][12][13][14][15][16]. In these works we have described the synthesis of the monomers (acid dichlorides, diphenols, diamines, or bischloroformates) and polymers, and all of them were characterized including 29 Si NMR spectroscopy when it corresponds.…”

Poly(urethanes) containing silarylene and/or germarylene units

“…So, poly(esters), poly(amides), poly(imides), poly(thiocarbonates), and poly(carbonates) containing silaryleneand/or germarylene-units in their structure have been prepared. [8][9][10][11][12][13][14][15] Several organic groups have been bonded to the central heteroatoms. In general, all polymers present low molecular weights and those polymers with Ge showed a small improvement in the thermal stability in comparison with the analogous with Si, which has been related to the differences in the polarity of the heteroatom-C bond and to the higher bond energy of the CÀ ÀGe bond in relation to the CÀ ÀSi one.…”

Synthesis and low-temperature dehydrating imidation polymerization of 1,4-dihydro-1,4-diarsininetetracarboxylic acid dianhydride

“…Among the various types of such polymers, much attention has been paid to heteroatomcontaining polyimides in attempts to develop high-performance functional polymers, such as high-refractive-index polymers for optical applications, polymers resistant to atomic oxygen and ultraviolet radiation, as well as thermostable polymers. [6][7][8][9][10] Organoarsenic compounds are currently being considered as ligands for transition metals because of their special properties; 11,12 however, fewer studies have been conducted with these than with their phosphorus analogs, because most organoarsenic compounds are prepared from arsenic chlorides or arsenic hydrides and require extreme caution in handling because of their volatility and toxicity. We previously reported the facile synthesis of a novel cis-1,4-diarsa-2,5-cyclohexadiene, that is, cis-1,4-dihydro-1,4-dimethyl-2,3,5,6-tetrakis(t-butoxycarbonyl)-1,4-diarsinine (cis-DHDAtBu), which was synthesized by the radical reaction of pentamethylcyclopentaarsine (cyclo-(MeAs) 5 ) and di-t-butyl acetylenedicarboxylate.…”