Using Chain Extenders to Modify Release Rates of Orange Oil from Poly(Urea-Urethane) Microcapsules

Jurij Pušla

doi:10.17344/acsi.2015.1434

Abstract

Poly(urea-urethane) and polyurea microcapsules were prepared by an interfacial polymerisation using orange oil as a core material and a mixture of polymeric 4,4'-methylene diphenyl diisocyanate and toluene diisocyanate in a molar ratio of 1:0.2 as oil-soluble monomers. The membrane composition, thickness, and other properties were varied by changing the type and amount of oil-soluble monomers and water-soluble chain extenders, such as ethylenediamine and diethylenetriamine based on amine groups and 1,4-butanediol and polyethylene glycol 400 based on hydroxyl groups. Studies of the morphology and release behaviour show high dependency on the reaction conditions and reactants' properties. The release rate of the orange oil from microcapsules is highest when using a polymeric linear chain extender, polyethylene glycol with a molecular mass of 400. Microcapsules with improved mechanical stability and a slower release rate were obtained by a thicker membrane and by using the branched multi-functional chain extender diethylenetriamine.

Highlights

Microencapsulation is typically used to enhance material stability, reduce adverse or toxic effects, improve handling properties, or extend the release of material for different applications
The membrane composition, thickness, and other properties were varied by changing the type and amount of oil-soluble monomers and water-soluble chain extenders, such as ethylenediamine and diethylenetriamine based on amine groups and 1,4-butanediol and polyethylene glycol 400 based on hydroxyl groups
This study investigated the properties of poly(ureaurethane) and polyurea microcapsules prepared by an interfacial polymerisation with various chain extenders in the aqueous phase, which were added at a higher temperature (75 °C) than in the conventional process (20 °C) in order to avoid agglomeration

Summary

Introduction

Microencapsulation is typically used to enhance material stability, reduce adverse or toxic effects, improve handling properties, or extend the release of material for different applications. A polyurethane-polyurea system prepared by interfacial polymerisation appears to be more attractive The membrane of such a system has good mechanical properties, is chemically inert with a low tendency to form agglomerates and, is formaldehyde-free. The results of previous studies on polyurethane/urea microcapsules[22,23,24,25] indicate that the process of interfacial polymerisation is very complex and many parameters affect the membrane formation. This study investigated the properties of poly(ureaurethane) and polyurea microcapsules prepared by an interfacial polymerisation with various chain extenders in the aqueous phase, which were added at a higher temperature (75 °C) than in the conventional process (20 °C) in order to avoid agglomeration. The effect of different membrane thicknesses on the microcapsule properties was investigated

Experimental

A2 A3 B1 C1 D1

Results and Discussion

Conclusion