ORIGINAL PAPER Hydrophobic surface treatments of sunflower pith using eco-friendly processes Nade `ge Follain • Redouan Saiah • Kateryna Fatyeyeva • Nirina Randrianandrasana • Nathalie Leblanc • Ste ´phane Marais • Laurence Lecamp Received: 6 June 2014 / Accepted: 28 October 2014 / Published online: 6 November 2014 Ó Springer Science+Business Media Dordrecht 2014 Abstract The aim of the present paper is to report the reduction of the water uptake of sunflower pith, sustain- able raw by-product without current added-value in oilseed crops production. The water-sensitivity is ascribed to its structure, because mainly constituted of carbohydrates, due to the formation of additional hydrogen bondings with water molecules. Two environ- mentally-friendly approaches were applied to provide a modified layer presenting water resistance in surface of sunflower pith in order to keep its low-density property. The first approach based on vegetable oil corresponds to thermal and photochemical treatments. A thin layer of virgin or acrylated epoxidized soybean oil was sprayed on the pith surface, and thereafter was thermally cured or photocured, respectively. The second approach con- sisted in a solventless chemical modification of the pith surface by a cold plasma treatment. Both approaches were successfully performed: water resistance of sun- flower pith was clearly enhanced, especially with oil- based treatments; while maintaining its integrity. Devel- oping new and promising ecological water-resistant products of low density from sunflower pith is thought of increasing interest with potential practical applications. Keywords Sunflower pith  Hydrophobization  Photopolymerization  Plasma  Water sorption Introduction Raw agricultural by-products received considerable attention in the context of environmental concerns with the need of replacing widely-used petroleum- N. Follain  K. Fatyeyeva  S. Marais  L. Lecamp Normandie Universite ´, Rouen, France N. Follain (&)  K. Fatyeyeva  S. Marais Laboratoire Polyme `res, Biopolyme `res, Surfaces, Universite ´ de Rouen, Bd M. de Broglie, 76821 Mont Saint Aignan Cedex, France e-mail: nadege.follain@univ-rouen.fr N. Follain  K. Fatyeyeva  S. Marais  L. Lecamp UMR 6270 CNRS & FR 3038, 76821 Mont Saint Aignan Cedex, France R. Saiah  N. Randrianandrasana  N. Leblanc Esitpa, Unite ´ AGRI’TERR, 3 rue du Tronquet, CS 40118, 76134 Mont Saint Aignan Cedex, France Present Address: R. Saiah Green Research, GANIL, Campus Jules Horowitz, Bd Henri Becquerel, BP 55027, 14076 Caen Cedex 05, France L. Lecamp INSA de Rouen, Av. de l’Universite ´, 76801 Saint Etienne du Rouvray Cedex, France 123 Cellulose (2015) 22:245–259 DOI 10.1007/s10570-014-0490-1