News Application Areas Coatings Technologies
Hydrophobic paper coating with silicone oil-laden nano-silica as a sustainable packaging solution
Using a novel hybrid formulation of hydrophobic nanosilica and PMMA, an Indian research team has succeeded in transforming paper waste into highly effective, water-repellent packaging materials – fully in line with the principles of a circular economy.
In view of the worldwide bans on disposable plastics, interest in sustainable alternatives in the packaging sector is growing. In the present study, researchers developed a functional coating system that converts paper and cellulose waste into water-repellent materials with a self-cleaning effect. The basis for this is a nanoscale silicon dioxide that has been hydrophobically modified by physical impregnation with silicone oil. The particles have a diameter of about 20 nm and a specific surface area of 157 m²/g – enough to absorb up to 2.5 g of silicone oil per gram of silica.
The hydrophobic properties were verified by measuring the water contact angle. The contact angle of the modified silica was a maximum of 139°. Embedded in a PMMA matrix, a spreadable hybrid formulation is obtained that can be applied to paper substrates. Embedding in the cellulose fibre structure creates an effective barrier against water and moisture.
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Circular, lightweight and functional
Particularly innovative is the application of the coating to fibrous cellulose sludge – a typical by-product of paper production. The combination of PMMA and oil-laden nanosilica transformed this waste material into a functional, lightweight packaging substrate with contact angles of up to 142°, indicating very good water repellency.
The technology presented could play an important role in the transition to bio-based, recyclable packaging materials and opens up new prospects for the use of industrial by-products from paper production.
Source: Journal of Coatings Technology and Research, Volume 21, Pages 1131–1144, (2024)
