FLEXURAL PERFORMANCE OF POLYURETHANE/MULTI WALLED CARBON NANOTUBES FOAM COMPOSITES A.A.Sinar 1,a , Z.Firuz 1,b , M.A.Nur Azni 1,c , M.A.Hazizan 2,d and H.A.Sahrim 3,e 1 School of Materials Engineering, Universiti Malaysia Perlis, 02600 Jejawi, Perlis, Malaysia 2 School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang, Malaysia 3 School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia a sinar@unimap.edu.my, b firuz@unimap.edu.my, c azni.azizan89@gmail.com, d hazizan@usm.my, e sahrim@ukm.my Keywords: Flexural, polyurethane, multi walled carbon nanotubes, sandwich Abstract. Polyurethane (PU)/multiwalled carbon nanotubes (MWCNTs) foam composites were produced by reaction of based palm oil polyol (POP) with methylene diphenyl diisocyanate (MDI). The MWCNTs were added into PU foam with the percentages varied from 0 wt.% to 3 wt.%. Sandwich composites were prepared using hand lay-up method where Aluminium (Al) sheet as skin were stacked onto PU foam using Araldite adhesives. The PU/MWCNTs foam composites (PMFC) and PU/MWCNTs foam sandwich composites (PMFSC) were characterized using flexural test analysis. Observation showed higher value of flexural strength for PMFC and PMFSC at 0.5% incorporation of MWCNTs. The flexural strength of sandwich PU foam is higher with an average value of 159.38% than control PU foam, due to Al sheet act as ductile skin and prevents samples from rupture rapidly. The modeling using finite element analysis (NX Software-version 8.5) showed the displacement nodal magnitude for 0.5% PMFC (2.537 mm) are higher than 0.5% PMFSC (0.288 mm). Introduction Polyurethane (PU) is widely used in various applications as foams, elastomers, fibers, bulk plastics, surface coatings, adhesives and sealants [1]. The main characteristics of PU foam are high porosity, lightweight and good energy absorption capacity [2-4]. The foam were protects sensitive objects from damage by undergoing large deformation at constant crush stresses [5]. The monomers used to form PU foam are organic isocyanate and polyol which are mostly derived from petrochemical refining of crude oil and coals. Polyol can be synthesized or extracted from natural materials such as oils, plants or wood [1]. Palm oil is one of the most widely used plant oils in the world. Preparation of the PU from palm oil may expand the application of the oil in different areas as environment friendly materials, because of its renewability and abundance. Moreover, it may led to the replacement of petrochemical products by this naturally occurring plant oil [6]. PU foam materials are popular type of thermosetting resin used as core for fabricated sandwich composites. The sandwich structure capable to provide high bending stiffness coupled with light weight. The sandwich composites consist of face sheet (skin) and core materials have various application areas including marine, aeronautical and transportation industry. The major advantages of these systems over the traditional materials are the perfect flexural resistance and stiffness, low thermal, high corrosion resistance and acoustic conductivity. The metallic layers are generally used as skin materials and studied revealed that the flexural performance are mainly governed by the selection of skin [2,3,7]. The geometry and component properties significantly affected the failure modes of sandwich beams. Core shear, skin micro buckling and indentation beneath the middle loading roller were the main failure mechanisms observed in the experiments [3]. Mechanical, impact and thermal properties of polymers can be significantly enhanced by the incorporation of nanoclay particles in polymer matrix. Nanoclay particles tend to exfoliate and intercalate in a polymer under appropriate Applied Mechanics and Materials Vols. 754-755 (2015) pp 8-12 Submitted: 05.01.2015 © (2015) Trans Tech Publications, Switzerland Accepted: 05.01.2015 doi:10.4028/www.scientific.net/AMM.754-755.8 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 58.27.57.122-11/02/15,05:43:27)