Development of a continuous reactor for emulsion-based microencapsulation of hexyl acetate with a polyuria shell

Area of Science:

• Chemical Engineering
• Materials Science
• Process Chemistry

Background:

• Microencapsulation is predominantly a batch process, limiting scalability and efficiency.
• Continuous flow chemistry offers advantages in control and production rates for chemical synthesis.

Purpose of the Study:

• To develop and characterize a continuous reactor setup for microencapsulating an ester within a polyurea (PU) shell.
• To investigate the influence of reactor design on microcapsule properties and production.

Main Methods:

• Emulsion template generation in a recirculation loop with static mixers and Kenics®.
• Calorimetric measurements to assess energy dissipation.
• Curing in a coiled tube reactor with varying configurations.
• Micrograph analysis for capsule size distribution.

Main Results:

• The recycle pump significantly influences the final capsule size distribution.
• Achieved a continuous production rate of 198 g/h for dry PU microcapsules.
• Produced microcapsules with a mean diameter of 13.3 µm and 54 wt% core content.

Conclusions:

• A continuous flow system for polyurea microcapsule production was successfully realized.
• The developed method provides a scalable and efficient approach for microencapsulation.
• Reactor design parameters, particularly the recycle pump, are critical for controlling microcapsule characteristics.