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Philippe Michaud - One of the best experts on this subject based on the ideXlab platform.
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low molecular weight poly imide amide s obtained by copolycondensation of 4 4 methylenedi phenyl isocyanate Trimellitic anhydride and benzoic Acid in n methyl 2 pyrrolidone 2 structural defects observed by 1h and 13c nmr
Macromolecular Chemistry and Physics, 1996Co-Authors: Nathalie Sinteszydowicz, Quang Tho Pham, Philippe MichaudAbstract:The in depth examination (by 1 H and 13 C NMR, DSC, SEC and TGA) of the low-molecular-weight poly(imide-amide)s synthesized with the mixture [4,4'-methylenedi(phenyl isocyanate) (M) + Trimellitic Acid anhydride (T) + benzoic Acid (B)] in N-methyl-2-pyrrolidone (NMP) at temperatures lower than 180°C allowed the identification and quantitative determinations of all the unexpected and relatively stable structures. While amide functions are readily synthesized, the formation of imide from anhydride and isocyanate functions passes through 4-amido-1,2-benzenedicarboxylic Acid (T i ), 1,4-di-amido-2-benzenecarboxylic Acid (T) and disubstituted urea (u). At 180 °C T i completely disappears but traces of T and u remain ; thus, the formation of imide can never reach its theoretical quantity. Traces of moisture in NMP may play the role of catalyst in the formation of imide, and reaction mechanisms are proposed.
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low molecular weight poly imide amide s obtained by copolycondensation of 4 4 methylenedi phenyl isocyanate Trimellitic Acid anhydride and benzoic Acid in n methyl 2 pyrrolidone 1 the microstructure studied by 1h and 13c nmr
Macromolecular Chemistry and Physics, 1993Co-Authors: Nathalie Sinteszydowicz, Quang Tho Pham, Philippe MichaudAbstract:Low-molecular-weight poly(imide-amide)s (PIA) obtained by polycondensation at 180°C of 4,4'-methylenedi(phenyl isocyanate), Trimellitic Acid anhydride and benzoic Acid were studied by 1 H and 13 C NMR. Complementary 1 H and 13 C information was used to determine the distribution of II, IA, AA sequences and to show that the repartition of imide (I) and amide (A) groups along the chains is random. According to the composition of the monomer mixture, a slight deficiency of I is reproducibly observed. Non-reacted benzoic Acid is found, and unexpected traces of urea and amic Acid groups are present in the PIA chains
Nathalie Sinteszydowicz - One of the best experts on this subject based on the ideXlab platform.
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low molecular weight poly imide amide s obtained by copolycondensation of 4 4 methylenedi phenyl isocyanate Trimellitic anhydride and benzoic Acid in n methyl 2 pyrrolidone 2 structural defects observed by 1h and 13c nmr
Macromolecular Chemistry and Physics, 1996Co-Authors: Nathalie Sinteszydowicz, Quang Tho Pham, Philippe MichaudAbstract:The in depth examination (by 1 H and 13 C NMR, DSC, SEC and TGA) of the low-molecular-weight poly(imide-amide)s synthesized with the mixture [4,4'-methylenedi(phenyl isocyanate) (M) + Trimellitic Acid anhydride (T) + benzoic Acid (B)] in N-methyl-2-pyrrolidone (NMP) at temperatures lower than 180°C allowed the identification and quantitative determinations of all the unexpected and relatively stable structures. While amide functions are readily synthesized, the formation of imide from anhydride and isocyanate functions passes through 4-amido-1,2-benzenedicarboxylic Acid (T i ), 1,4-di-amido-2-benzenecarboxylic Acid (T) and disubstituted urea (u). At 180 °C T i completely disappears but traces of T and u remain ; thus, the formation of imide can never reach its theoretical quantity. Traces of moisture in NMP may play the role of catalyst in the formation of imide, and reaction mechanisms are proposed.
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low molecular weight poly imide amide s obtained by copolycondensation of 4 4 methylenedi phenyl isocyanate Trimellitic Acid anhydride and benzoic Acid in n methyl 2 pyrrolidone 1 the microstructure studied by 1h and 13c nmr
Macromolecular Chemistry and Physics, 1993Co-Authors: Nathalie Sinteszydowicz, Quang Tho Pham, Philippe MichaudAbstract:Low-molecular-weight poly(imide-amide)s (PIA) obtained by polycondensation at 180°C of 4,4'-methylenedi(phenyl isocyanate), Trimellitic Acid anhydride and benzoic Acid were studied by 1 H and 13 C NMR. Complementary 1 H and 13 C information was used to determine the distribution of II, IA, AA sequences and to show that the repartition of imide (I) and amide (A) groups along the chains is random. According to the composition of the monomer mixture, a slight deficiency of I is reproducibly observed. Non-reacted benzoic Acid is found, and unexpected traces of urea and amic Acid groups are present in the PIA chains
Quang Tho Pham - One of the best experts on this subject based on the ideXlab platform.
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low molecular weight poly imide amide s obtained by copolycondensation of 4 4 methylenedi phenyl isocyanate Trimellitic anhydride and benzoic Acid in n methyl 2 pyrrolidone 2 structural defects observed by 1h and 13c nmr
Macromolecular Chemistry and Physics, 1996Co-Authors: Nathalie Sinteszydowicz, Quang Tho Pham, Philippe MichaudAbstract:The in depth examination (by 1 H and 13 C NMR, DSC, SEC and TGA) of the low-molecular-weight poly(imide-amide)s synthesized with the mixture [4,4'-methylenedi(phenyl isocyanate) (M) + Trimellitic Acid anhydride (T) + benzoic Acid (B)] in N-methyl-2-pyrrolidone (NMP) at temperatures lower than 180°C allowed the identification and quantitative determinations of all the unexpected and relatively stable structures. While amide functions are readily synthesized, the formation of imide from anhydride and isocyanate functions passes through 4-amido-1,2-benzenedicarboxylic Acid (T i ), 1,4-di-amido-2-benzenecarboxylic Acid (T) and disubstituted urea (u). At 180 °C T i completely disappears but traces of T and u remain ; thus, the formation of imide can never reach its theoretical quantity. Traces of moisture in NMP may play the role of catalyst in the formation of imide, and reaction mechanisms are proposed.
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low molecular weight poly imide amide s obtained by copolycondensation of 4 4 methylenedi phenyl isocyanate Trimellitic Acid anhydride and benzoic Acid in n methyl 2 pyrrolidone 1 the microstructure studied by 1h and 13c nmr
Macromolecular Chemistry and Physics, 1993Co-Authors: Nathalie Sinteszydowicz, Quang Tho Pham, Philippe MichaudAbstract:Low-molecular-weight poly(imide-amide)s (PIA) obtained by polycondensation at 180°C of 4,4'-methylenedi(phenyl isocyanate), Trimellitic Acid anhydride and benzoic Acid were studied by 1 H and 13 C NMR. Complementary 1 H and 13 C information was used to determine the distribution of II, IA, AA sequences and to show that the repartition of imide (I) and amide (A) groups along the chains is random. According to the composition of the monomer mixture, a slight deficiency of I is reproducibly observed. Non-reacted benzoic Acid is found, and unexpected traces of urea and amic Acid groups are present in the PIA chains
Gert Schwarz - One of the best experts on this subject based on the ideXlab platform.
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lc poly ester amide imide s derived from Trimellitic Acid and 4 aminobenzoic Acid
Polymer, 1996Co-Authors: Helmut Reinecke, Hans R Kricheldorf, Joseg De La Campa, Javier De Abajo, Gert SchwarzAbstract:Abstract A new mesogene diester based on phenyltrimellitimide was synthesized and used as a condensation monomer in combination with a number of aliphatic diols to render novel poly(ester-amide-imide)s (PEAIs). The melt polycondensation method provided polymers of moderate inherent viscosity, that were characterized by elemental analyses, differential scanning calorimetry, X-ray diffractometry, including synchrotron radiation measurements at different temperatures, optical microscopy with polarized light and thermogravimetric analysis. The glass transition temperatures ( T g ) lie in the range 100–130°C, which means a substantial improvement relative to analogous poly(ester-imide)s (PEIs). All the novel PEAIs are thermotropic materials that show a mobile LC-mesophase above the melting temperature. By combining microscopic observations with X-ray diffraction diagrams, the mesophases could be identified as smectic-A phases. PEAIs with even-numbered spacers are semi-crystalline in the solid state, while those with odd-numbered spacers can form a solid smectic glass phase, i.e. a frozen smectic-A phase, upon rapid cooling from the melt.
Weize Wu - One of the best experts on this subject based on the ideXlab platform.
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separation of the isomers of benzene poly carboxylic Acid s by quaternary ammonium salt via formation of deep eutectic solvents
Journal of Physical Chemistry B, 2014Co-Authors: Jian Li, Weize WuAbstract:Because of similar properties and very low volatility, isomers of benzene poly(carboxylic Acid)s (BPCAs) are very difficult to separate. In this work, we found that isomers of BPCAs could be separated efficiently by quaternary ammonium salts (QASs) via formation of deep eutectic solvents (DESs). Three kinds of QASs were used to separate the isomers of BPCAs, including the isomers of benzene tricarboxylic Acids (Trimellitic Acid, trimesic Acid, and hemimellitic Acid) and the isomers of benzene dicarboxylic Acids (phthalic Acid and isophthalic Acid). Among the QASs, tetraethylammonium chloride was found to have the best performance, which could completely separate BPCA isomers in methyl ethyl ketone solutions. It was found that the hydrogen bond forming between QAS and BPCA results in the selective separation of BPCA isomers. QAS in DES was regenerated effectively by the antisolvent method, and the regenerated QAS was reused four times with the same high efficiency.
