Please cite this article in press as: Kaoukabi, A., et al., The use of ionic liquids as an organocatalyst for controlled ring-opening polymer- ization of -caprolactone. Ind. Crops Prod. (2015), http://dx.doi.org/10.1016/j.indcrop.2015.02.002 ARTICLE IN PRESS G Model INDCRO-7830; No. of Pages 8 Industrial Crops and Products xxx (2015) xxx–xxx Contents lists available at ScienceDirect Industrial Crops and Products jo ur nal home p age: www.elsevier.com/locate/indcrop The use of ionic liquids as an organocatalyst for controlled ring-opening polymerization of -caprolactone Asmae Kaoukabi a,b , Frédéric Guillen b,c , Hicham Qayouh a,b , Asmaa Bouyahya a,b , Sébastien Balieu b , Larbi Belachemi a , Géraldine Gouhier b,∗∗ , Mohammed Lahcini a,∗ a Laboratoire de Chimie Organométallique et Macromoléculaire-Matériaux Composites (LCO2MC), Faculté des Sciences et Techniques Guéliz, Université Cadi Ayyad, Av. Abdelkrim Khattabi BP 549. Marrakech, 40000 Marrakech, Morocco b Normandie Université, COBRA UMR 6014, FR 3038, INSA Rouen, CNRS IRCOF 1 rue Tesnière, 76821 Mont-Saint-Aignan, France c CNRS UMR 5068, SPCMIB, Université Toulouse III Paul Sabatier, 118 route de Narbonne, F-31062 Toulouse Cedex 9, France a r t i c l e i n f o Article history: Received 18 October 2014 Received in revised form 22 January 2015 Accepted 2 February 2015 Available online xxx Keywords: Aliphatic polyesters Ring-opening polymerization -Caprolactone Ionic liquids IR spectroscopic a b s t r a c t The controlled ring-opening polymerization of -caprolactone in bulk catalyzed by ionic liquids, thus, avoiding the use of metal catalyst, solvent and base, is reported. These mild conditions led to living poly- merization with good conversions and molecular weight distributions of poly(-caprolactone). Finally, an activation mechanism is suggested based on the results of an in-situ FTIR polymerization analysis using various ionic liquid catalysts. © 2015 Published by Elsevier B.V. 1. Introduction Aliphatic polyesters such as poly(lactide), poly(glycolide), poly(-caprolactone) and their copolymers are among the most promising biodegradable polymers (Jérôme and Lecomte, 2008). They are biocompatible, enzymatically and chemically degradable and bioresorbable due to a total metabolization of the degradation products. Poly(-caprolactone) (P-CL), in particular, is permeable to low molecular mass molecules at human body temperature and its degradation rate is slower than poly(glycolide) or copoly- mer of poly(lactide) rates; for these reasons, P-CL and their copolymers are frequently used for biomedical applications, such as absorbable surgery sutures, drug delivery systems, or tissue engineering (Albertsson and Varma, 2002). At the industrial level this polymer is readily obtained in a controlled manner via the ring-opening polymerization of -caprolactone (-CL) by using cat- alysts based on transition and post-transition metals such as tin, aluminum, iron, yttrium, zinc, bismuth, ruthenium, and zirconium ∗ Corresponding author. Tel: +212 668267776; fax: +212 24433170. ∗∗ Corresponding author. Present address: Princess Nora Bint Abdulrahman Uni- versity, PO Box 84,428, Riyadh, Saudi Arabia. Tel.: +966 011 824 2409. E-mail addresses: geraldine.gouhier@univ-rouen.fr (G. Gouhier), m.lahcini@uca.ma (M. Lahcini). (Arbaoui and Reshaw, 2010). The drawback of these homogeneous systems is the contamination of the resulting polyesters by residual metal that should be avoided for medical use. Therefore, organocat- alyzed ring-opening polymerization has emerged as a promising alternative to its metal-catalyzed counterpart (Kiesewetter et al., 2010). Metal free catalysis for ring-opening polymerization of lactones was carried out by activation of the monomer using a Brønsted acid (Bourissou et al., 2005) or a catalytic nucleophile (Nederberg et al., 2001; Kricheldorf et al., 2008; Dove et al., 2006), by activation of the nucleophilic growing polymer chain using a base (Lohmeijer et al., 2006; Zhang et al., 2007), or via a dual activation of both reacting species using a thiourea/tertiary amine system (Dove et al., 2005; Pratt et al., 2006) or phospho- ric (Delcroix et al., 2011), or sulfonic (Susperregui et al., 2010) acids. Recently, the ring-opening polymerization of lactones and lactides was described in imidazolium based ionic liquids (IL) in the presence of a nucleophilic catalyst such as in-situ generated carbene (Nyce et al., 2003) or DMAP (Dai et al., 2012; Guo et al., 2013; Luan et al., 2013), Lewis acid (Yubing et al., 2007; Nomura et al., 2007), tin octanoate (Guo et al., 2013) or even an enzyme (Marcilla et al., 2006; Chanfreau et al., 2010; Mena et al., 2010; Gumel et al., 2012). N,N  -Dialkylimidazolium-based ionic liquids were shown to act as a catalyst in the polymerization of L-lactic acid oligomers at high temperatures (Wang et al., 2008). Zhu in 2009 published ring-opening polymerization of -caprolactone in http://dx.doi.org/10.1016/j.indcrop.2015.02.002 0926-6690/© 2015 Published by Elsevier B.V.