The role of equilibrium state of the reaction of formation of polyamido acids in the process of their thermal cyclization in solution

Kardash, I. E.; Ardashnikov, A.Ya.; Lavrov, Sergey; Праведников, А.Н.

doi:10.1007/bf00952499

Cited by 5 publications

(5 citation statements)

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“…In our work [26], we used the method of one-pot high-temperature polycondensation in molten BA at 140°C for synthesis of HB PIs with reactive anhydride Figure 13. Typical curves of change in time of the concentration of imide cycles (1,2) and triads: aa (3), bb (4), ab (5). Figure 14.…”

Section: Synthesis Of (Hyper)branched (Hb) Polyimidesmentioning

confidence: 99%

“…The fundamental aspects of the two-stage process of PI synthesis have been the subject of detailed study of many researchers [1][2][3]. One of the fundamentally important results obtained was the conclusion that the formation of polyamic acids (PAA) is a reversible reaction [4,5]; the equilibrium constant and degree of polymerization are controlled by the solvent basicity and temperature. This means that to obtain a PAA with a high degree of polymerization, the process is to be carried out in highly basic (amic) solvents at 20-40°C.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Polyimides in the Melt of Benzoic Acid

Alexeevich¹,

Yurievna²

2020

Solvents, Ionic Liquids and Solvent Effects

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Review of the authors' works on the synthesis of polyimides (PIs) by the method of one-stage high-temperature polycondensation in an unusual solvent-molten benzoic acid (BA). Compared with a known synthesis in inert high-boiling solvents, synthesis in BA takes place under mild conditions (140°C, 1-2 hour) to give completely imidized PIs. The approach has a number of advantages. Due to catalysis of the first reversible stage of amiс acid (AA) formation and low equilibrium constant (K = 10-20 l/mol), the first stage disappears kinetically, and the imidization reaction becomes limiting. The process becomes less sensitive to the basicity of diamines; therefore, low reactivity diamines can be involved. Water is easily removed from the melt by evaporation, which makes the whole process irreversible. Specific features of the method are successfully used to control the microstructure of the chain copolyimides (statistical to multiblock) and to synthesize hyperbranched PIs and star-shaped PIs with narrow molecular weight distribution.

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Section: Synthesis Of (Hyper)branched (Hb) Polyimidesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of Polyimides in the Melt of Benzoic Acid

Alexeevich¹,

Yurievna²

2020

Solvents, Ionic Liquids and Solvent Effects

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“…It was also established that, for the given processes, there is good correlation between the equilibrium constant and the heat effect of the reaction (ref. 16). Therefore, the use of the calorimetric method to study the kinetics of the overall process of PAA formation is quite justified.…”

Section: Coohmentioning

confidence: 99%

Kinetic Laws Governing the Synthesis of Adamantane-Containing Polyamido Acids and Polyimides

Новаков

Orlinson

Заиков

2001

International Polymer Science and Technology

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“…In particular, the synthesis of CPI by the HTPC method proceeds via two stages rather than one, and the first stage is revers ible. 19 The formation of the CPI microstructure was not earlier analyzed for a similar process.…”

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Formation of the chain microstructure in copolyimide synthesis by high-temperature polycondensation in molten benzoic acid

et al. 2014

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Kinetic features of chain microstructure formation in the synthesis of copolyimides with five membered imide cycles were studied by the high temperature polycondensation method in molten benzoic acid from two diamines A and B (comonomers) and one dianhydride C (intermonomer) at 140 C using different regimes of intermonomer loading. The kinetic scheme, including (for the first and second comonomers) the acylation of the amino group with the anhydride fragment, decomposition, and imidization of intermediate amido acid fragments, was examined. The kinetic parameters of the acylation stage necessary for calculation were determined for the model reactions of 9,9 bis(4 aminophenyl)fluorene and 1,12 dodecameth ylenediamine with phthalic anhydride in acetic acid. The numerical solution of the system of kinetic equations for different regimes of intermonomer loading gave the calculated depen dences of the change in time of the average block length and current concentrations of amino and anhydride groups, amido acid fragments (unstable dyads АС 1 and ВС 1 ), imide cycles (stable dyads АС 2 and ВС 2 ), and triads. The calculated values of the average block length (l  4) and microheterogeneity parameter of the chain (K m  0.5) for the gradual intermonomer loading correspond to the multiblock structure of the chain. These values are in good agreement with the experimental values obtained from the data of 13 C NMR spectroscopy for copolyimide based on the indicated diamines and 2,2 propylidenebis(phenyl 4 oxyphthalic acid) dianhydride.

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The role of equilibrium state of the reaction of formation of polyamido acids in the process of their thermal cyclization in solution

Cited by 5 publications

References 0 publications

Synthesis of Polyimides in the Melt of Benzoic Acid

Synthesis of Polyimides in the Melt of Benzoic Acid

Kinetic Laws Governing the Synthesis of Adamantane-Containing Polyamido Acids and Polyimides

Formation of the chain microstructure in copolyimide synthesis by high-temperature polycondensation in molten benzoic acid

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