Polyamide microcapsules for controlled release. II. Release characteristics of the microcapsules

Abstract Microcapsules of various polyamides were investigated as regards their release characteristics at room temperature, at 100/dgC, and on being heated at a uniform rate (TGA). It was found that membranes of linear polyamides are more permeable to the core material than are membranes of cross-linked polyamides. Estimates are made of the critical internal pressures leading to rupture, and for one membrane the breaking strengths obtained in several ways are compared. It is estimated that for membranes of cross-linked polyamides a pressure of about 14 atm in the core is required to rupture the microcapsule wall.