M A Abu Bakar* ABSTRACT
Mechanical and Thermal Properties of LENR Modified Epoxy Composite
Faculty of Mechanical Engineering
Universiti Teknologi MARA, (UiTM) Shah Alam
School of Applied Physics
Faculty of Science & Technology
Universiti Kebangsaan Malaysia, UKM Bangi
Epoxy resins are considered as one of the most important classes of thermosetting
polymers for many industrial applications and become an important matrix in
polymer composites. However polymerization of this resin resulted in brittleness
due to high crosslinking level. Due to this matter, many efforts have been made to
improve the toughness of cured epoxy resins by the introduction of rigid particles,
reactive rubbers, interpenetrating polymer networks and thermoplastics within
the matrix. Incorporation of small amount of rubber is one of the approaches to
improve fracture toughness of the epoxy matrix. In this work, the flexural and
impact properties of liquid epoxidized natural rubber (LENR) modified epoxy
composites have been studied. Addition of LENR increased the impact strength
of the epoxy resin. The impact strength increased from to 18.357 kJ/m2, when
modified with 5.5 phr LENR. The SEM analysis shows uniform dispersion of
rubber particles within the epoxy matrix with average particle size less than
Keywords: Epoxy resin, modified epoxy, liquid epoxidized natural rubber
(LENR), impact strength, toughened epoxy
 Dipa Ray and Jogeswari Rout (2005). Natural Fibers, Biopolymers and
Biocomposites, Taylor and Francis, 291-341.
 Payam Saadati, Habibollah Baharvand, Azam Rahimi and Jalil Morshedian
(2005). Effect of modified liquid rubber on increasing toughness of epoxy
resins, Iranian Polymer J, 14(7), 637-646.
 Calabrese, L. and Valenza, A. (2003). Effect of CTBN rubber inclusions
on the curing kinetic of DGEBA-DGEBF epoxy resin, European Polymer
J, 39, 1355-1363.
 Raju Thomas, Sebastien Durix, Christophe Sinturel, Tolib Omonov, Sara
Goossens, Gabriel Groninckx, Paula Moldenaers and Sabu Thomas (2007).
Cure kinetics, morphology and miscibility of modified DGEBA-based
epoxy resin – Effects of a liquid rubber inclusion, Polymer, 48, 1695-
 Auad, M.L., Frontini, P.M., Borrajo, J. and Aranguren, M.I. (2001). Liquid
rubber modified vinyl ester resins: fracture and mechanical behavior,
Polymer, 42, 3723-3730.
 Jyongsik Jang and Hojung Yang (2000). Toughness improvement of
carbon-fibre/polybenzoxazine composites by rubber modification,
Composites Science and Technology, 60, 457-463.
 Ozturk, A., Kaynak, C. and Tincer, T. (2001). Effects of liquid rubber
modification on the behavior of epoxy resin, European Polymer J, 37,
 Raju Thomas, Ding Yumei, He Yuelong, Yang Le, Paula Moldenaers,
Yang Weimin, Tibor Czigany and Sabu Thomas (2008). Miscibility,
morphology, thermal and mechanical properties of a DGEBA based epoxy
resin toughened with a liquid rubber, Polymer, 49, 278-294.
 Cevdet Kaynak, Ozgur Orgun and Teoman Tincer (2005). Matrix and
interface modification of short carbon fiber-reinforced epoxy, Polymer
Testing, 24, 455-462.
 Laurent Jayle, Clive B. Bucknall, Ivana K. Partridge, John N. Hay, Alan
Fernyhough and Ikuo Nozue (1996). Ternary blends of epoxy, rubber
and polycarbonate: phase behaviour, mechanical properties and chemical
interactions, Polymer, 37(10), 1897-1996.
 Abdullah, I. and Zakaria, Z. (1989). Pendepolimeran fotokimia getah asli,
Sains Malaysiana, 18(2), 99-109.
 Abadyan, M., Khademi, V., Bagheri, R., Kouchakzadeh, M.A. and Farsadi
M. (2009). Use of rubber modification technique to improve fractureresistance
of hoop wound composites, Materials and Design, 30, 1976-
 Ismail Zainol, Mohamad Ibrahim Ahmad, Fadzil Ayad Zakaria, Anita
Ramli, Haslan Fadli Ahmad Marzuki and Azizan Abdul Aziz (2006).
Modification of epoxy resin using liquid natural rubber, Materials Science
Forum, 517, 272-274.
 Valeria D. Ramos, Helson M. da Costa, Vera L.P. Soares and Regina
S.V. Nascimento, (2005). Modification of epoxy resin: A comparison of
different types of elastomer, Polymer Testing, 24, 387-394.
 Varaporn Tanrattanakul, Nutthorn Sungthong and Phatchareeya Raksa
(2008). Rubber toughening of nylon 6 with epoxidized natural rubber,
Polymer Testing, 27, 794-800.
M A Abu Bakar*