Progress in Organic Coatings 105 (2017) 48–55 Contents lists available at ScienceDirect Progress in Organic Coatings journal homepage: www.elsevier.com/locate/porgcoat A one step route synthesis of polyurethane newtwork from epoxidized rapeseed oil Yesmine Fourati a , Ramzi Bel Hassen a , Gülay Bayramo˘ glu b , Sami Boufi a,∗ a University of Sfax, Faculty of Science, LMSE, BP 1171, 3000 Sfax, Tunisie b Yalova Universitesi Mühendislik Fakültesi Stad kars ¸ ısı, Turkey a r t i c l e i n f o Article history: Received 2 December 2016 Received in revised form 25 December 2016 Accepted 26 December 2016 Keywords: Epoxydized rapeseed oil Polyurethane Isocyanate Crosslinking a b s t r a c t Biobased polyurethane networks were prepared by a one step curing epoxidized rapeseed oil (ERO) with isophorone diisocyanate (IPDI) as a hardener at 130 ◦ C. The in-situ monitoring of the curing process by FTIR has confirmed the progressive consumption of the oxirane ring and the isocyanate function along with the emergence of the urethane groups. Investigation of model systems using phenyl isocyanate confirmed the ring opening of oxirane during the reaction between ERO and the isocyanate. Based on the spectroscopic investigation, it was hypothesised that the reaction started by the condensation between hydroxyl groups of ERO and isocyanate. Then, the oxirane was ring-opened by the urethane group and the hydroxyl group further reacted with isocyanate. The glass transition of the polyurethane network as well as the stiffness and strength were shown to be strongly dependent on the ratio between ERO and IPDI. Polyurethane film from ERO/IPDI in a ratio 80/20 results in a transparent elastic film with a T g around −20 ◦ C and a tensile modulus and strength of1.5 and 9.4 MPa, respectively. © 2016 Elsevier B.V. All rights reserved. 1. Introduction Over the last decade, there has been a growing interest for biobased polymers derived from renewable biomass due to the increasing awareness of environmental issues, depleting of petroleum resources in the near future and the need for sustain- able resource without compromising food security. In this context, vegetable oils are highly suitable starting materials for polymers due to their ready availability, inherent biodegradability and low toxicity [1,2]. Vegetable oils have been used in paints and coat- ings for centuries, because the unsaturated oils can be crosslinked via oxy-polymerization when exposed to the oxygen in air [3]. The wide possibility to generate a large panels of polymerizable func- tionalities, including epoxy, aldehydes or carboxylic acids through the chemistry of the double bond, is another driving force to the increasing interest in vegetable oils. Oil can be also used as a precursor to create large oligomeric macromonomers, or through controlled cross-linking, and even to prepare polymers through olefin cross-metathesis [4]. Epoxidized oils, especially epoxidized soybean oils, are the most readily available chemically modified oils in the world [5] ∗ Corresponding author. E-mail address: sami.boufi@fss.rnu.tn (S. Boufi). at a relatively low price. The epoxidation is typically carried out using peroxy (performic or peracetic) acid generated in-situ from carboxylic acid and hydrogen peroxide [6]. Epoxidized oils are commercially available at a reasonable cost and are a promising intermediate for chemical modification because of reactive epoxy groups. Epoxidized vegetable oils and epoxidized fatty acids are largely used as thermal stabilizer plasticizers and antioxidants for PVC [7] as they offer ease of processing and improve flexibility. ESO can be used as lubricants because of high index viscosity, good thermal stability, low volatility, and good lubricity. EO can be used in manufacturing intermediate chemicals and monomers using a wide possible chemical pathway, including hydrolysis, acry- lation, ethoxylation, propoxylation, hydroxylation, hydrogenation, and carbonation. The resulting monomers possessing desirable functionalities can be used in polymers thermoset, adhesive or coating. Epoxidized plant oils can be cured in similar ways as petroleum-based epoxy counterparts by reaction with polyamine [8], anhydride [9], mercaptans [10], imidazoles, and acids [11]. Polyurethane (PU) is one of the most widely investigated classes of synthetic polymers, exhibiting versatile properties suitable for use in practically all fields of polymer applications foams, elas- tomers, thermoplastics, adhesives, coatings, sealants, fibers, and so on. PUs are obtained by the reaction of an oligomeric polyol (low molecular weight polymer with terminal hydroxyl groups) and a diisocyanate (or polyisocyanate). The use of biobased polyol from http://dx.doi.org/10.1016/j.porgcoat.2016.12.021 0300-9440/© 2016 Elsevier B.V. All rights reserved.