Premium
Control of urethane prepolymerization from reaction kinetics and viscosity
Author(s) -
Chaffey Charles E.,
Orchanian Samuel
Publication year - 1973
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1973.070170124
Subject(s) - prepolymer , activation energy , reaction rate constant , kinetics , viscosity , order of reaction , polyurethane , polymer chemistry , diluent , chemical kinetics , chemistry , reaction rate , toluene , thermodynamics , materials science , first order , catalysis , organic chemistry , composite material , physics , mathematics , quantum mechanics
A theory of the kinetics of consective second‐order reactions has been generalized and used to interpret observations of toluene‐2,4‐diisocyanate reacting with polyoxypropylene glycol without diluent or catalyst to form a urethane prepolymer. The first reaction in the sequence has a second‐order rate constant of 1.2 × 10 −7 m 3 mole −1 sec −1 at 303°K with an activation energy of 3.5 × 10 4 J mole −1 . The rate constant of the second reaction appears to be one half of this. Deviations from the theoretical kinetics and an increase in the viscosity of the prepolymer product above 1.9 kg m −1 s −1 (measured at 313°K) when the temperature of reaction exceeds about 360°K show that above this temperature, undesirable side reactions are important.