Substitution Effects in Property Relations for Stepwise Polyfunctional Polymerization

Abstract

This paper extends the authors' method of calculating average properties of ideal nonlinear stepwise polymerization to systems with first-shell substitution effects. Two special cases are considered in detail: A/ + B2, where the second and subsequent A groups on the A¡ monomer can react at different rates due to the presence of other reacted groups, and A^+ A2 + B2, where both A¡ and A2 can show substitution effects. Relations for weight-average molecular weight, the gel point, weight-fraction solubles, and cross-link density are derived.

Applicability of Statistical Theories of Network Formation

“…The equilibrium formulation was used in the past as approximation for irreversible bond formation (cf., e.g., [3,4,13,14,[28][29][30][31][32] ), For a kinetically controlled system, the dependence of transition probabilities on structure evolution parameter (time, conversion) is different. For irreversible reactions, bonds once formed remain intact as the reaction proceeds and cannot be transformed into bonds of other types, a process possible in reversible reactions including the equilibrium state.…”

Step Polymerization

“…If both of the conditions stated are present, that is, r ¼ r ¼ where we have reactants ranging from monofunctional to ith functional for A functional groups and monofunctional to jth functional for B functional groups [Durand and Bruneau, 1982a,b;Miller et al, 1979;Miller and Macosko, 1978;Stockmayer, 1952Stockmayer, , 1953Stafford, 1981.] The extent of reaction at the gel point is given by…”

Influence of sequence of chemical reactions on kinetics and solid state behavior for bisphenol A diglycidyl ether—bisphenol A—sulfanilamide ternary blends

“…As before, these products result from the epoxy + amine reaction. At this stage assuming that there is no (or little) reaction of the amide groups, SAA could be considered as difunctional monomer and the mass average molar mass can be calculated using the treatment of Macosko and Miller [25,26] with the usual assumptions of equal reactivity of functional groups of the same type and the absence of intramolecular reaction. M w may be expressed as: (5) where M AA = molar mass of sulfanilamide; M EE = molar mass of DGEBA; r = A/E with the assumption that a groups do not react; x A = extent of reaction of A groups (amino-hydrogen groups).…”