Fluorination renders the wood surface hydrophobic without any
Fluorination renders the wood surface hydrophobic without any loss of physical and mechanical properties M. Pouzet, M. Dubois, K. Charlet, A. Beakou, J. M. Leban, M. Baba 2019
INTRODUCTION • Wood is hygroscopic material => change in humidity and temperature cause swelling or shrinking • Preventation methods that are in use • Chemical treatment (varnish, protections) => wear off, toxicity • Modification of wood structure (thermal treatment => brittleness
BACKROUND • Fluorination • Fluorine gas (F 2) has been used to • Reinforce wood/polymer composites by improving hydrophobicity of wood material • Fluorinate natural fibres to gain better understanding => Lignin is necessary to achieve successful natural fibre fluorination. Cellulose limits fluorination • This is because Fluorine substitutes –OH groups of cellulose Tämä kuva, tekijä Tuntematon tekijä, käyttöoikeus: CC BY-SA
RESEARCH QUESTIONS • Can fluorination of massive wood improve its hydrophobicity without risking mechanical properties and resistance of UV-radiation?
MAIN METHODS • Silver Fir and Douglas Fir samples were used (10 x 1 x 0, 8 cm) • Dried samples were exposed to F 2/N 2 gaseous flow at room temperature for 1, 5, 10, 20, 40, 60 minutes • Tensile and flexural strengths of samples were tested • Hygroscopicity of samples was tested by measuring angles of water droplets contact surfaces • UV-resistance was tested by exposing samples to UV-radiation
MAIN RESULTS • Hygroscopicity • Adsorption time was greater with fluorinated samples excluding samples that were fluorinated over 40 minutes • This is because fluorination deteriorates cellulose making it more porous
MAIN RESULTS • Mechanical properties • No distinct difference between refenece and fluorinated samples
MAIN RESULTS • UV-resistance • No impact
MAIN CONCLUSIONS • Fluorination • Decreases hygroscopicity of wood => optimal treatment 5 min • Does not affect to woods mechanical properties when fluorination time < 40 minutes • Does not affect to UV-resistance of wood
Own thoughts • Okay, sounds great! • But, • How much does it cost? • Could it be used industrially cost effectively? • Is the fluorination process safe?
Thank you! Questions?
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