Slow-DEET-Release Mosquito-Repellent System Based on Poly(butylene succinate)

Area of Science:

• Polymer Science
• Materials Science
• Entomology

Background:

• Mosquito-borne diseases necessitate effective and sustainable repellent solutions.
• Biodegradable polymers offer environmentally friendly alternatives for controlled release applications.
• N,N-diethyl-3-methylbenzamide (DEET) is a widely used and effective insect repellent.

Purpose of the Study:

• To develop and characterize biodegradable poly(butylene succinate) (PBS) strands containing DEET.
• To evaluate the evaporation characteristics of DEET from PBS matrices.
• To assess the potential of these strands as slow-release repellent-delivery devices.

Main Methods:

• Extrusion of bio-sourced and biodegradable PBS with varying DEET concentrations (up to 40 m%).
• Microstructural analysis to observe DEET entrapment within the PBS superstructure.
• Thermogravimetric analysis (TGA) at temperatures ranging from 60-100 °C to quantify DEET release.
• Estimation of evaporation rates and time constants at lower service temperatures.

Main Results:

• DEET was successfully incorporated into PBS strands via extrusion.
• At DEET concentrations up to 20 m%, DEET was entrapped within the semicrystalline spherulitic superstructure of PBS.
• At higher DEET concentrations (>20 m%), DEET partially segregated, forming its own macrophase.
• Thermogravimetric analysis indicated an extremely low DEET release rate, with an estimated time constant of 1-2 years at 25 °C, irrespective of initial DEET concentration.

Conclusions:

• Biodegradable PBS strands can effectively encapsulate DEET for controlled release applications.
• The developed materials exhibit exceptionally slow evaporation rates, suggesting long-term efficacy.
• These DEET-loaded PBS strands hold promise as sustainable, slow-release mosquito repellent devices.