Sains Malaysiana 40(7)(2011): 679–683

Effects of Liquid Natural Rubber (LNR) on the Mechanical Properties of LNR Toughened Epoxy Composite

(Kesan Getah Asli Cecair (LNR) Terhadap Sifat-Sifat Mekanik Komposit Epoksi Diperkuat LNR)

Lee Yip Seng*, Sahrim Hj. Ahmad, Rozaidi Rasid, Se Yong Eh Noum, Yew Chin Hock & Mou’ad A. Tarawneh

School of Applied Physics, Faculty of Science & Technology

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E. Malaysia

Diserahkan: 23 Oktober 2009 / Diterima: 5 Ogos 2010

ABSTRACT

The effects of liquid natural rubber (LNR) on the morphology and mechanical properties of rubber modified epoxy were investigated. Epoxy composites were prepared in four different compositions of LNR (3, 5, 7 and 9phr) by using twin screw extruder. The samples for tensile, fracture toughness and impact tests were prepared according to ASTM D 638, D 5045 and D 256. The elastomeric nature of rubber can act as energy dissipating centre to cause the ductile fracture for the rubber modified epoxy. They was an obvious increment of fracture toughness where maximum value was observed with 3 phr LNR. A clear increment of impact strength at 3 phr LNR was observed, followed by a small increment at 5 phr and no further increment at 7 and 9 phr LNR. The tensile strength showed a similar trend with impact strength and Young’s modulus. SEM micrographs showed an increment of rubber particle size when the amount of LNR was increased and caused the mechanical properties to drop.

Keywords: Epoxy resin; liquid natural rubber; mechanical properties; toughness

ABSTRAK

Kesan getah asli cecair (LNR) terhadap morfologi dan sifat-sifat mekanik bagi komposit epoksi telah dikaji. Komposit epoksi disediakan di dalam empat komposisi LNR (3, 5, 7 & 9 phr) dengan menggunakan mesin penyemperitan skru-berkembar. Sampel bagi ujian tegangan, keliatan patahan dan hentaman disediakan mengikuti ASTM D 638, D 5045 and D 256. Elastomer getah dapat bertindak sebagai pusat penyesapan tenaga dan menyebabkan kepatahan mulur berlaku bagi epoksi termodifikasi getah. Peningkatan keliatan patahan yang jelas didapati dengan nilai maksimum adalah pada 3 phr LNR. Kenaikan yang jelas didapati bagi kekuatan hentaman pada 3 phr LNR dan diikuti dengan kenaikan kecil di 5 phr dan tiada kenaikan lebih lanjut pada 7 dan 9 phr LNR. Kekuatan tegangan telah menunjukkan satu kecenderungan yang sama dengan kekuatan hentaman dan modulus Young. Mikrograf SEM jelas menunjukkan kenaikan saiz partikel getah apabila jumlah LNR meningkat dan menyebabkan penurunan sifat-sifat mekanik.

Kata kunci: Keliatan; getah asli cecair; resin epoksi; sifat mekanik

RUJUKAN

Balakrishnan, S., Start, P.R., Raghavan, D. & Hudson, S.D. 2005. The influence of clay and elastomer concentration on the morphology and fracture energy of performed acrylic rubber dispersed clay filled epoxy nanocomposites. Polymer 46: 11255-11262.

Bascom, W.D. & Hunston, D.L. 1989. Fracture of elastomer-modified epoxy polymer: a review. In. Riew, C.K. (ed.). Rubber-Toughened Plastics, pp. 135-172. Washington: American Chemical Society.

Chikhi, N., Fellahi, S., Bakar, M. 2002. Modification of epoxy resin using of reactive liquid (ATBN) rubber. European Polymer Journal 38: 251-264.

Huang, Y., Hunston, D.L., Kinloch, A.J. & Riew, C.K. 1993. Mechanisms of toughening thermoset resins. In. Riew, C.K. & Kinloch, A.J. (ed.). Toughened Plastics I, pp. 1-38. Washington: American Chemical Society.

Ibrahim, A. & Sahrim, A. 1992. Liquid natural rubber as a compatibiliser in the blending of natural rubber with polypropylene. Materials Forum 16: 353-357.

Ibrahim, A. & Zuriati, Z. 1989. Pendepolimeran fotokimia getah asli. Sains Malaysiana (18)2: 99-109.

Kinloch, A.J. 1989. Relationship between the microstructure and frature behavior of rubber-toughened thermosetting polymer. In. Riew, C.K. (ed.). Rubber-Toughened Plastics, pp. 67-92. Washington: American Chemical Society.

Kinloch, A.J. & Hunston, D.L. 1987. Effect of volume fraction of dispersed rubbery phase on the toughness of rubber-toughened epoxy polymers. Journal of Materials Science Letters 6: 131-139.

Kinloch, A.J., Shaw, S.J., Tod, D.A. & Hunston, D.L. 1983. Deformation and fracture behaviour of a rubber-toughened epoxy: 1. Microstructure and fracture studies. Polymer 24: 1341-1354.

Lee, W.H., Hodd, K.A. & Wright, W.W. 1989. Phase-separation and transition phenomena in toughened epoxies. In. Riew, C.K. (ed.). Rubber-Toughened Plastics, pp. 263-287. Washington: American Chemical Society.

Mulhaupt, R. & Buchholz, U. 1996. Compatibilized, segmented liquid rubbers as epoxy-toughening agents. In. Riew, C.K. & Kinloch, A.J. (ed.) Toughened Plastics II, pp. 75-94. Washington: America Chemical Society.

Ozturk, A., Kaynak, C. & Tincer, T. 2001. Effects of liquid rubber modification on the behaviour of epoxy resin. European Polymer Journal. 37: 2353-2363.

Pearson, R.A., & Yee, A.F. 1993. Toughening mechanisms in thermoplastic-modified epoxies: 1. Modification using poly(phenylene oxide). Polymer 34(17): 3658-3670.

Ratna, D. 2001. Phase separation in liquid rubber modified epoxy mixture. Relationship between curing conditions, morphology and ultimate behavior. Polymer 42: 4209-4218.

Ratna, D. & Simon, G.P. 2001. Mechanical characterization and morphology of carboxyl randomized poly(2-ethyl hexyl acrylate) liquid rubber toughened epoxy resins. Polymer 42: 7739-7747.

Saadati, P., Baharvand, H., Rahimi, A. & Morshedian, J. 2005. Effect of modified liquid rubber on increasing toughness of epoxy resins. Iranian Polymer Journal 14(7): 637-646.

Seymour, R.B. 1989. Origin and early development of rubber-toughened plastics. In. Riew, C.K. (ed.). Rubber-Toughened Plastics, pp. 3-13. Washington: American Chemical Society.

Thomas, R., Ding, Y., He, Y., Yang, L., Moldenaers, P., Yang, W., Czigany, T. & Thomas, S. 2008. Miscibility, morphology, thermal, and mechanical properties of a DGEBA based epoxy resin toughened with a liquid rubber. Polymer 49: 278-294.

*Pengarang untuk surat-menyurat; email: jansennlee@hotmail.com