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A kinetic approach to multifunctional polymerization with cyclization
Author(s) -
Kumar Anil,
Misra Sanjay
Publication year - 1986
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.760261903
Subject(s) - dispersity , polymerization , intramolecular force , molar mass distribution , monomer , polymer , gel point , polymer chemistry , materials science , kinetic chain length , kinetic energy , chain (unit) , kinetic scheme , reaction rate constant , thermodynamics , kinetics , solution polymerization , chemistry , organic chemistry , composite material , physics , classical mechanics , astronomy
A kinetic model for the step growth polymerization of multifunctional monomers RA f valid up to the gel point has been presented which accounts for the intramolecular reactions. From the Jacobson‐Stockmeyer equation, the average rats constant for this step has been derived and is found to be chain length dependent. A computation scheme has been evolved by which the molecular weight distribution of the linear, branched as well as cyclized polymer can be determined up to the gel point. It is found that even though the molecular weight distribution of cyclic oligomers is little affected for the range of the values of the intramolecular rate constant ( k c ) studied, the average chain length μ n and the polydispersity index p of the polymer formed are extremely sensitive to k c near the gel point. Numerical computations confirm that as the gel point is approached, larger polymer chains are formed which have a higher tendency to react intramolecularly. However, even at high conversions the number of the cyclic rings per polymer chain remains small, which is consistent with experimentally observed results.