Formation, properties and rheology of paraffin wax oil-in-water emulsions. Stabilizing effect of novel EO/PO/EO block copolymer fatty acid monoesters

Paraffin wax oil-in-water emulsions were stabilized by a series of fatty acid monoesters of EO-PO-EO triblock copolymer. The emulsions with an average droplet size in the range of 370-570 nm were formed using a two-step pressure homogenization method. The emulsions were characterized by their physicochemical, advanced microrheology (DWS), and droplet aggregation (Zeta potential) properties. The other types of potential insta-bility were identified by static multiple light scattering in static conditions. The results were correlated with those obtained in rheological studies in dynamic conditions. The properties of the paraffin wax emulsions varied with the fatty acid alkyl chain length and hydrophilic-lipophilic balance (HLB) values. The obtained paraffin wax emulsions were used as coatings to obtain hydrophobized papers, and the barrier properties against moisture were improved. The emulsion formed moderately hydrophobic layer on paper, their contact angle between coated paper and water was 61-67 degrees. Obtained stable and hydrophobic paraffin emulsion, due to the use of safe components, can be used e.g. for the production of hydrophobic coatings for packaging.

Automated summary

A stable paraffin wax oil-in-water emulsion was developed and found to have hydrophobic properties, making it suitable for coating packaging materials.