Journal of Colloid and Interface Science 289 (2005) 249–261 www.elsevier.com/locate/jcis Silane adsorption onto cellulose fibers: Hydrolysis and condensation reactions Marie-Christine Brochier Salon a , Makki Abdelmouleh b , Sami Boufi b , Mohamed Naceur Belgacem a,∗ , Alessandro Gandini c a LGP2, Ecole Française de Papeterie et des Industries Graphiques (INPG), BP 65, Domaine Universitaire, F-38402 St. Martin d’Hères, France b LMSE, Faculté des sciences de Sfax, BP 802-3018 Sfax, Tunisia c Instituto de Química de São Carlos, Universidade de São Paulo, Av. Trabalhador São Carlense, 400, CEP 13566-590 São Carlos, SP, Brazil Received 23 February 2005; accepted 25 March 2005 Available online 23 May 2005 Abstract The hydrolysis of three alkoxysilane coupling agents, γ -methacryloxypropyltrimethoxysilane (MPS), γ -aminopropyltriethoxysilane (APS), and γ -diethylenetriaminopropyltrimethoxysilane (TAS), was carried out in an ethanol/water (80/20) solution and followed by 1 H, 13 C, and 29 Si NMR spectroscopy, which showed that its rate increased in the order MPS < APS < TAS. The formation of the silanol groups was followed by their self-condensation to generate oligomeric structure. APS and MPS only gave soluble products, whereas colloidal parti- cles precipitated in the medium when TAS was hydrolyzed. Pristine and hydrolyzed MPS were then adsorbed onto a cellulose substrate and thereafter a thermal treatment at 110–120 ◦ C under reduced pressure was applied to the modified fibers to create permanent bonding of the coupling agent at their surface.  2005 Elsevier Inc. All rights reserved. 1. Introduction Functional trialkoxysilanes, R ′ Si(OR) 3 , are widely used in numerous industrial applications as coupling agents, to enhance adhesion between polymeric matrices and inorganic solids [1–5]. The mechanisms of these coupling reactions are related to the presence of two types of reactive moieties in their structure, which respond in different ways, according to the substrates they approach. On one hand, the alkoxy groups OR enable the silane to be anchored to surfaces bearing hydroxyl groups [6–8], and on the other hand, the organic functionality R ′ (amine, methacrylic, vinylic, etc.) improves their compatibility, or even copolymerizes with organic matrices, thus enhancing the interfacial adhesion be- tween the two phases [9,10]. * Corresponding author. Fax: +33 (0) 4 76 82 69 33. E-mail address: naceur.belgacem@efpg.inpg.fr (M.N. Belgacem). Usually, the surface treatment is carried out with a silane water–alcohol solution in a concentration range of 0.5–2% by weight. These conditions offer several advantages, in par- ticular (i) an increase of silane solubilization in the medium, (ii) better control of the film thickness on the surface, and (iii) more uniform coverage of the surface. The water in- duces stepwise hydrolysis of the silane [5,11] to give the cor- responding silanol derivative R ′ -Si(OH) 3 , which promotes the silane adsorption onto OH-rich substrates through hy- drogen bonding. The actual chemical condensation is known to occur after thermal activation, leading to siloxane bridges [4,12,13], as follows: . 0021-9797/$ – see front matter  2005 Elsevier Inc. All rights reserved. doi:10.1016/j.jcis.2005.03.070