Luis H. Tagle

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 ¹H, ¹³C and ²⁹Si 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 CSi bond compared with the CGe one, and due to the lower size of the Si atom that presents lower rotational barriers. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2768–2776, 2006

Poly(carbonates) and poly(thiocarbonates) containing silicon in the main chain and derived from the diphenols bis(4-hydroxyphenyl)-dimethylsilane, bis(4-hydroxyphenyl)-ethylmethylsilane, and bis(4-hydroxyphenyl)-diethylsilane with phosgene or thiophosgene, respectively, were synthesized under phase transfer conditions, using several phase transfer catalysts. Polymers were characterized by spectroscopic methods (IR and ¹ H, ¹³ C, ²⁹ Si NMR) and the results were evaluated by the yields and the η _inh values. In general the effectiveness of the phase transfer process was low, the best results being obtained when the NaOH concentration was increased from the stoichiometric due to a salting-out effect. However, at higher concentrations hydrolytic process were observed. Poly(carbonates) and poly(thiocarbonates) showed, in general, the same trend with the catalysts.

Poly(carbonates) and poly(thiocarbonates), containing germanium in the main chain and derived from the diphenols bis(4‐hydroxyphenyl)‐dimethyl‐germane, bis(4‐hydroxyphenyl)‐diethyl‐germane, and bis(4‐hydroxyphenyl)‐dibutyl‐germane reaction with phosgene and thiophosgene, respectively. The products were synthesized under phase transfer conditions, using two phase transfer catalysts. The products were characterized by spectroscopic methods. The results were evaluated by the yields and η_inh values which showed different behaviors for poly(carbonates) and poly(thiocarbonates). The yields and the η_inh values for the poly(carbonates) were low due to a hydrolytic process when the NaOH concentration was increased. For the poly(thiocarbonates) the phase transfer was effective and also there was an increase of both parameters when the NaOH concentration was increased, due to a salting out effect.

Poly(carbonates), poly(thiocarbonates) and poly(esteres) containing silicon and/or germanium in the main chain were obtained under phase transfer conditions. Polymers were synthesized in a biphasic system NaOH/CH₂Cl₂ at 20°C using several phase transfer catalysts, and characterized by IR and ¹H and ¹³C NMR. The results were evaluated by the yields and the inherent viscosity values. The process was effective observing an increase of both parameters in comparison with the essays without catalyst. The increases depended of the nature of the polymer and the catalyst. In poly(ester) synthesis there was an increase of these parameters when the NaOH concentration was increased due to a salting out effect of the diphenolate from the aqueous phase to the organic one. Also poly(amides) containing silicon or germanium were synthesized by solution polymerization.

Poly(N-1-alkylitaconamic acid) (PNAIA) containing ethyl, propyl, butyl, hexyl, octyl, decyl and dodecyl groups and random N-1-alkylitaconamic acid-co-styrene copolymers (NAIA-co-S) of three different compositions were selected and studied by dynamic thermogravimetric analysis (TGA). The thermal stability of homopolymers and copolymers depends on the structure of the NAIA and on the composition of the copolymer. The kinetic analysis of the degradation data shows that the thermal decomposition of the PNAIA can be described by zero order kinetic model. In the case of NAIA-co-S copolymers, the degradation process can be described by two different kinetic orders depending on the copolymer and on the composition. The thermal stability of the PNAIA in general increases as the length of the side chain increases. In the case of copolymers with styrene the relative thermal stability depends clearly on the composition and on the type of substituent in the side chain.