| Abstrakt: |
The initial products for continuous polycondensation in fabrication of PPBT were investigated: polyphosphoric acid (PPA), P2O5, and 2,5-diamino-1,4-dimercaptobenzene diphosphate (DADMB). Criteria were found for assessing their properties that satisfy the requirements of synthesis. The spectral criteria of formation of the product of addition of PPA to DADMB in the initial stages of polycondensation were established and suggested a strong reaction between the components (on the level of a chemical reaction); the kinetics of the initial stages of synthesis of PPBT at different temperatures was investigated. The very pronounced extremal character of the kinetic curves describing the initial and subsequent stage of synthesis in spectral parameters suggests the formation of a product of addition at the extremal point and the appearance of several extrema on the kinetic curves indicates the discrete character of the addition process. The results of the kinetic studies of the initial stages of the polycondensation can be used in selecting the optimum temperature-time regime of conducting them. [ABSTRACT FROM AUTHOR] |
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