Interfacial polycondensation. II. Fundamentals of polymer formation at liquid interfaces

Abstract

If a solution of a fast‐reacting diacid halide in a water‐immiscible solvent is brought together with an aqueous solution of a diamine without stirring, a thin film of high polymer is formed at once at the interface. Polyurethanes and polyamides in particular form tough films which can be grasped and pulled continuously from the interface as a folded rope of film. This unstirred interfacial polycondensation not only provides a dramatic demonstration of polymer formation but has permitted the observation of polymerization behavior and the study of the effects of many variables upon the process. The polymer‐forming reactions proceed by nucleophilic displacement, and many have rate constants of at least 102–104 1. mole−1 sec. −1. Polymers derived from diamines were found to form in the organic solvent phase. Therefore the rate of polymer formation is controlled by the transfer of diamine from the aqueous phase. It is believed that the liquid interface does not have any beneficial orienting effect on the reactants but that it provides for the regulated flow of one reactant into an excess of the other. Furthermore, the aqueous phase provides for the removal of the interfering byproduct, hydrogen halide, from the polymerization site. Some of the interrelated variables which have been studied and which are discussed in relation to the physical mechanism are the solvent sensitivity of the polymer, partition coefficients of the reactants, reactant concentration, duration of the polymerization, and the addition of monofunctional reactants, detergents, and salts. The formation of polyphenyl esters is discussed briefly.

An experimental study of polyurea membrane formation by interfacial polycondensation

“…It is also possible that some diffusion limitations arise in this case as the value of n L /V d (and hence the final film thickness) is quite high. Based on the ratios in the first two cases therefore, we may conclude that the rate constant in the case of cyclohexane is about twice that in CCl 4 .…”

“…However, quantitative understanding of IP lags behind that of other established techniques, such as melt and solution polymerization. Experimental information on the influence of preparation conditions on polymer film properties, such as the molecular weight, crystallinity, permeability, etc., is scanty [4,5]. Other work, for example on membrane casting from polymer solutions, shows that the film microstructure, and consequent properties such as film density and permeability are affected significantly by the polymer precipitation mechanism [6].…”

Pressure Retarded Osmosis and Forward Osmosis Membranes: Materials and Methods

“…They found the Schotten-Bauman reaction to be the basis of this simple, versatile laboratory process [75,76]. Cadotte first introduced the concept of IP-coating on membranes to obtain osmotic TFC membranes [6].…”

“…In 1959 Emerson et al introduced the concept of interfacial polymerization (IP); dissolving the monomers in two immiscible liquids so that the reaction takes place at the liquid-liquid interface [75,76]. The acid chloride is usually dissolved in an organic solvent (e.g., hexane, cyclohexane, isopar) and the amine in water.…”

Ag-Nylon Nanocomposites by Dynamic Emulsion Polycondensation

“…Therefore, the reaction is believed to occur effectively in the nonpolar solvent but at close proximity of the interface. The polymer product accumulating at the interface in the form of a thin film has to be simultaneously removed, which otherwise blocks the monomer diffusion to the interface from polar to nonpolar side [16].…”