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Solid‐state polymerization in poly(butylene terephthalate): The Equilibrium constant
Author(s) -
Kosky P. G.,
Guggenheim E. A.
Publication year - 1985
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760251806
Subject(s) - materials science , polymerization , polymer , equilibrium constant , melting point , polymer chemistry , butanediol , infrared spectroscopy , titanium , condensation polymer , 1,4 butanediol , chemical engineering , chemistry , organic chemistry , composite material , catalysis , fermentation , engineering , metallurgy
Poly(butylene terephthalate) PBT or Poly‐1, 4‐butanediyl 1, 4‐diearboxylate. polycondenses readily in the presence of small amounts of organo‐titanium compounds to form progressively higher molecular weight polymers, The reaction is reversible in the presence of the condensation byproduct, 1,4‐butanediol. Usually this reaction is carried out in the melt phase, but the viscosity is soon limiting. In the current work the polymerization is carried out in the solid phase just below the melting point of 227°C. The equilibrium constant for this reaction is measured by subjecting the polymer to a nitrogen stream saturated with a controlled quantity of butanediol. The reaction is followed by measuring the change in the number of alcoholic end‐groups by infrared spectroscopy. At about 220°C the equilibrium constant is 0.31 (σ = 0.08).