Influence of the contents of epoxy resin modified by castor oil (ECO), 4,4’- diamino diphenyl methan (DDM) on the crosslinking reaction of ECO by DDM at 180 oC have been studied and mol ratio of A/E = 1, curing time of 270 min have been determined to be the optimal conditions for formation of the cured coating having gel fraction, swelling degree, flexibility, adhesion, impact resistance, and relative hardness of 86 %; 188 %; 1 mm, 0 point, 200 and , respectively. | Journal of Science and Technology 54 (4) (2016) 501-508 DOI: STUDY OF THE INFLUENCE OF CONSTITUENT RATIO ON THE CROSSLINKING REACTION OF CASTOR OIL MODIFIED EPOXY RESIN BY ’-DIAMINO DIPHENYLMETHANE Do Minh Thanh1, *, Le Xuan Hien1, Nguyen Tien Dung2 1 2 Institute for Tropical Technology, VAST, 18 Hoang Quoc Viet, Cau Giay, Hanoi Faculty of Chemistry, Hanoi National University of Education, 136 Xuan Thuy, Hanoi * Email: Received: 21 September 2015, Accepted for publication: 16 March 2016 ABSTRACT Influence of the contents of epoxy resin modified by castor oil (ECO), 4,4’- diamino diphenyl methan (DDM) on the crosslinking reaction of ECO by DDM at 180 oC have been studied and mol ratio of A/E = 1, curing time of 270 min have been determined to be the optimal conditions for formation of the cured coating having gel fraction, swelling degree, flexibility, adhesion, impact resistance, and relative hardness of 86 %; 188 %; 1 mm, 0 point, 200 and , respectively. Keywords: epoxy resin, castor oil, 4,4’- diamino diphenyl methane, curing. 1. INTRODUCTION Thanks to epoxy, hydroxyl groups and double bonds, epoxy resins modified by unsaturated triglyceride vegetable oils can be chemically converted or cured by different methods [1-5]. The published research results of the Laboratory for Rubber and Natural Resins Material (LRNRM), Institue for Tropical Technology (ITT) showed that systems based on epoxy resin modified by soyabean oil and DDM can be cured at high temperature with formation of high performance coatings [5]. Therefor, DDM have been used for curing of epoxy resins modified by various vegetable oils. This work presents some results of the study of the influence of constituent ratio on the crosslinking reaction of castor oil modified epoxy resin by 4,4’-diamino diphenylmethane. 2. EXPERIMENTAL . Materials Epoxy resin modified by castor oil having epoxy content of 2 mol/kg, oil content of 39 % was
