Synthesis of Oligomeric Silicon-containing Poly(imide-amide)s Derived from Trimellitic Anhydride and Amino-Acids. Vibration Spectral, Optical, Thermal and Morphological Characterization

Abstract

Poly(imide-amide)s (PIAs) were synthesized from diacids, which were obtained by trimellitic anhydride and glycine, L-alanine, Lphenylalanine, L-valine, L-leucine, L-isoleucine and p-aminobenzoic acid, and bis(4-aminophenyl)diphenylsilane. Compounds were characterized by elemental analysis, optical activity, IR and NMR spectroscopies. Yields were good, but η inh values were low, showing materials of oligomeric nature, confirmed by MALDI-TOF spectrometry. PIAs were soluble in polar aprotic solvents, while those derived from amino acids with bulky side groups were soluble in CHCl 3 and acetone. The wavenumber of vibrational bands were compared by Infrared and Raman spectroscopy. However, the high fluorescence emitted for PIAs, difficult to predict the vibrations of certain functional groups by Raman spectroscopy. The incorporation of chiral, amide and imide moieties interrupt the conjugation and increase the flexibility of the system. In addition, the adjacent phenyl units from the silicon-containing diamine, disfavors the planar conformation, which affects the optical properties showing an insulator behavior. DSC analyses showed that PIA-VII of aromatic nature had the higher glass transition temperature (Tg) value. For the other PIAs the Tg values decreased when volume of the side groups was increased, with the exception of PIA-VI derived from L-isoleucine. The thermal decomposition temperatures showed that only PIA-VII derived from p-aminobenzoic acid was thermostable. For the other PIAs it was possible to see a decrease of the TDT values when the size of the side chain is increased. The size and shape of the polymeric particles were studied by Scanning Electronic Microscopy (SEM), showing a relation between structure, incorporation of rigid aromatic rings and voluminous group into the system.

Silarylene-containing oligo(ether-amide)s based on bis(4-(4-amino phenoxy)phenyl)dimethylsilane. Effect of the dicarboxylic acid structure on some properties

“…From these works, several polymerizations have been developed with diamines containing diphenylsilane unit (Ph-Si-Ph), where the silicon atom is bonded to combinations of R 1 ¼ methyl and R 2 ¼ phenyl 8 as well as R 1 ¼ R 2 ¼ methyl 6,9 or phenyl. 6,[9][10][11][12][13][14][15][16][17][18][19][20] On the other hand, the inclusion of ether linkages into the chain of PAs has been explored by several research groups. Thus, diverse difunctional monomers have been synthesized and the properties of the derived polymers were established, with special attention to the solubility and their thermal parameters.…”

Molten salt-supported polycondensation of optically active diacid monomers with an aromatic thiazole-bearing diamine using microwave irradiation

“…In the polycondensation reactions, we use natural amino acids as chiral inducting agents [18] . Chiral polymers containing amino acids are of great interest in scientific research and technological innovation because they are expected to be nontoxic and can be employed for biomedical applications [19–21] . Furthermore, a high degree of amino acid functionality can lead to polymers with increased solubility and the ability to form secondary structures [22] .…”

Silicon-containing oligomeric poly(imido-amides) with amino moieties. Synthesis, characterization and thermal studies

“…This effect was described for us in other work. 39 Respect to the 29 Si NMR, it was possible to see the corresponding signal to the Si atom at high eld. If the signal corresponding to the Si atom bonded to four aromatic rings (dicarboxylic imido-acids III-(a-g)) is considered like a reference about À13.5 ppm, the signal corresponding to the other dicarboxylic imido-acids II-(a-g) with one methyl group and three phenyl rings bonded to the Si atom, is shied to lower eld at about À9.0 ppm.…”

“…33,34 Also the synthesis of Si-containing polymers including two functional groups like poly(imide-amides) or poly(imide-ethers) have been described as examples of materials with exible units which improve the solubility maintaining the thermal resistance. 24 Continuing our works about of Si-containing condensation polymers, [35][36][37][38][39][40][41][42] we describe the synthesis of poly(imide-amides) containing two Si atoms and both functional groups, imide and amide. In fact, dianhydrides with a Si atom in their structure reacted with several natural L-amino acids and p-aminobenzoic acid in order to obtain monomeric dicarboxylic acids with the imide group and a exible aliphatic residue provided by the amino acid, which were polymerized with an aromatic diamine containing another Si atom as central element.…”