ABSTRACT:
This study investigates the formulation and characterization of stable microemulsions using neem oil methyl ester as the oil phase and cardphenol ethoxylate surfactants with varying hydrophilic-lipophilic balance (HLB) values. Neem oil methyl ester was characterized and exhibited favourable physicochemical properties including specific gravity of 0.873, acid value of 0.12, and viscosity of 4.3 mm²/s at 40°C. Eight surfactant blends were prepared using cardphenol ethoxylated 9 mole (CP-9, HLB 11.9) and cardphenol ethoxylated 15 mole (CP-15, HLB 13.9) in different proportions, with and without isopropyl alcohol ethoxylated 2 moles (IPA-2) as co-solvent. Pseudo-ternary phase diagrams were constructed using the aqueous titration method to identify microemulsion regions for each blend. Both water-in-oil (W/O) and oil-in-water (O/W) type microemulsions were successfully formulated and characterized for pH, density, electrical conductivity, and particle size. The W/O microemulsions exhibited particle sizes ranging from 99 to 174 nm with conductivity values between 70.3 and 100 µS/cm, while O/W microemulsions showed particle sizes of 121 to 179 nm with higher conductivity values ranging from 230.4 to 344.2 µS/cm. All formulations demonstrated excellent centrifuge stability both initially and after 30 days of storage. The results indicate that Blend 5 (90% CP-9, 10% CP-15 with IPA-2 at 1:1 ratio, HLB 12.1) produced the smallest particle size of 99 nm for W/O microemulsions, while Blend 5 also yielded the smallest O/W particle size of 121 nm, suggesting optimal surfactant composition for enhanced microemulsion stability. These findings demonstrate the potential of cardphenol ethoxylate-based surfactant systems for developing stable neem oil methyl ester microemulsions with applications in agricultural formulations and bio-based delivery systems.
Cite this article:
Harshal Patil, Jyotsna Waghmare. Formulation and Characterization of Cardphenol Ethoxylate Based Microemulsion of Neem Oil Methyl Ester. International Journal of Technology. 2026; 16(1):35-2. doi: 10.52711/2231-3915.2026.00004
Cite(Electronic):
Harshal Patil, Jyotsna Waghmare. Formulation and Characterization of Cardphenol Ethoxylate Based Microemulsion of Neem Oil Methyl Ester. International Journal of Technology. 2026; 16(1):35-2. doi: 10.52711/2231-3915.2026.00004 Available on: https://ijtonline.com/AbstractView.aspx?PID=2026-16-1-4
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