Synthesis of Polyamide-Based Microcapsules via Interfacial Polymerization: Effect of Key Process Parameters

Abstract

Polyamide microcapsules have gathered significant research interest during the past years due to their good barrier properties; however, the potential of their application is limited due to the fragility of the polymeric membrane. Fully aliphatic polyamide microcapsules (PA MCs) were herein prepared from ethylene diamine and sebacoyl chloride via interfacial polymerization, and the effect of key encapsulation parameters, i.e., monomers ratio, core solvent, stirring rate and time during the polymerization step, were examined concerning attainable process yield and microcapsule properties (shell molecular weight and thermal properties, MC size and morphology). The process yield was found to be mainly influenced by the nature of the organic solvent, which was correlated to the diffusion potential of the diamine from the aqueous phase to the organic core through the polyamide membrane. Thus, spherical microcapsules with a size between 14 and 90 μm and a yield of 33% were prepared by using toluene as core solvent. Milder stirring during the polymerization step led to an improved microcapsule morphology; yet, the substantial improvement of mechanical properties remains a challenge.

Status of Research on the Use of Nanomodified Microcapsules in Cement-Based Materials

“…The method used to prepare nanomodified microcapsules determines their macroscopic properties and how they affect materials. Typical synthesis methods include in situ polymerization, interfacial polymerization, spray drying, solvent evaporation, sol-gel, and Pickering emulsion methods [48][49][50][51][52][53][54]. In situ polymerization is the most frequently used method because of its simple and convenient reaction conditions and process, and because the microcapsule size can be controlled by varying the stirring speed [55].…”

Self‐lubricating polyamide 6 and polyamide 6.6 microcapsule‐based composites

“…The mechanical behavior and appearance of the microcapsules differs from that of PA microcapsules prepared by other authors. Thus, in 33 fully aliphatic microcapsules with toluene core were prepared by interfacial polymerization. The air-dried microcapsules observed via SEM are not spherical; their shape suggests that microcapsule wall is very thin and remained flexible until most of the core material has been evaporated.…”

Preparation, Characterization, and Bioactivity Evaluation of Lambda-Cyhalothrin Microcapsules for Slow-Controlled Release System

“…It also reduces skin irritation and toxicity of some pesticides to users and delays the development of resistance to the target. There are various methods for the preparation of microcapsules, including in situ polymerization, interfacial polymerization, , emulsion polymerization, double-emulsion method, and solvent evaporation …”

“…It also reduces skin irritation and toxicity of some pesticides to users and delays the development of resistance to the target. There are various methods for the preparation of microcapsules, including in situ polymerization, 14 interfacial polymerization, 15,16 emulsion polymerization, 17 double-emulsion method, 18 and solvent evaporation. 19 Interfacial polymerization is one of the most commonly used methods to produce pesticide microcapsules; it has the unique advantages of high encapsulation rate, good thermal stability, and good slow release and has become the mainstream method for microcapsule preparation in the field of pesticide preparation.…”