Sains Malaysiana 44(11)(2015): 1615–1623

Mechanical, Thermal and Chemical Resistance of Epoxidized Natural Rubber Toughened Polylactic Acid Blends

(Rintangan Mekanikal, Termal dan Kimia Adunan Asid Polilaktik Diperkukuhkan dengan Getah Asli Terepoksida)

MAT UZIR WAHIT¹*, AZMAN HASSAN², AKOS NOEL IBRAHIM², NURHAYATI AHMAD ZAWAWI² & KAYATHRE KUNASEGERAN²

¹Center for Composites (CfC), Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim

Malaysia

²Enhanced Polymer Research Group (EnPRO), Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor Darul Takzim

Malaysia

Diserahkan: 28 Mac 2015 /Diterima: 12 Jun 2015

ABSTRACT

Polylactic acid (PLA)/Epoxidized natural rubber (ENR-50) blends were prepared by melt extrusion followed by injection molding to fabricate the test samples. The effect of ENR-50 loadings on the morphological, mechanical, chemical resistance and water absorption properties of the blends were studied using standard methods. The toughness of the blend improved with ENR loading up to 20 wt. % but flexural and tensile strength decreased. The balanced mechanical properties were obtained at 20 wt. % ENR-50 loading. SEM showed good distribution and increased ENR particle size as ENR content increased from 10 to 30 wt. %. The differential scanning calorimeter (DSC) showed a steady drop in crystallization temperature (T_c) as ENR content increases while the glass transition temperature (T_g) remained unchanged. Water absorption was observed to increase with ENR loadings. Increase in ENR content was also observed to reduce the chemical resistance of the blends.

Keywords: Blend; epoxidized natural rubber; extrusion; mechanical properties; polylactic acids

ABSTRAK

Adunan asid polilaktik (PLA)/getah asli terepoksida (ENR 50) disediakan dengan menggunakan kaedah penyemperitan leburan dan diikuti dengan kaedah pengacuan suntikan untuk menghasilkan sampel untuk pengujian. Kesan kandungan ENR 50 terhadap ciri morfologi, mekanik, rintangan kimia dan penyerapan air dikaji dengan menggunakan kaedah piawai. Kadar keliatan adunan tersebut meningkat dengan peningkatan kandungan ENR sehingga 20% tetapi kadar kelenturan dan tegangan menurun. Ciri mekanik yang seimbang diperoleh dengan 20% kandungan ENR 50. Imej SEM menunjukkan penyerakan ENR 50 yang baik dan peningkatan saiz partikel selari dengan peningkatan ENR daripada 10% ke 30%. Kalorimeter imbasan pembezaan (DSC) menunjukkan penurunan suhu penghabluran kristal yang stabil dengan peningkatan kandungan ENR 50, manakala suhu peralihan kaca kekal tidak berubah. Kadar penyerapan air didapati meningkat dengan peningkatan kandungan ENR 50. Peningkatan kandungan ENR juga dilihat dapat mengurangkan rintangan kimia adunan tersebut.

Kata kunci: Adunan; asid polilaktik; getah asli terepoksida; penyemperitan; sifat mekanik

RUJUKAN

Abdelwahab, M.A., Allison, F., Bor-Sen, C., Syed, I., William, O. & Emo, C. 2012. Thermal, mechanical and morphological characterization of plasticized PLA-PHB blends. Polymer Degradation and Stability 97: 1822-1828.

Ahmad Sharif, N.F., Mohamad, Z., Hassan, A. & Wahit, M.U. 2011. Novel epoxidized natural rubber toughened polyamide 6/halloysite nanotubes nanocomposites. Journal of Polymer Research 19: 1-10.

Akbari, A., Jawaid, M., Hassan, A. & Balakrishnan, H. 2013. Epoxidized natural rubber toughened polylactic acid/ talc composites: Mechanical, thermal, and morphological properties. Journal of Composite Materials 48(7): 769-781.

Baker, C.S.L. & Gelling, I.R. 1987. Epoxidised natural rubber. In Developments in Rubber Technology, edited by Wheelan, A. & Lee, K.S. Netherlands: Springer. pp. 87-117.

Borggreve, R.J.M., Gaymans, R.J., Schuijer, J. & Housz, I. 1987. Brittle-tough transition in nylon-rubber blends: Effect of rubber concentration and particle size. Polymer 28: 1489- 1496.

Bucknall, C.B. 1977. Toughened Plastics. Essex, England: Applied Science Publishers Ltd.

Calvão, P.S., Chenal, J-M., Gauthier, C., Demarquette, N.R., Dos Santos, A.M. & Cavaille, J.V. 2010. Influence of the rubbery phase on the crystallinity and thermomechanical properties of poly(3-hydroxybutyrate)/elastomer blends. Polymer International 59: 851-858.

Chuayjuljit, S., Soatthiyanon, N. & Potiyaraj, P. 2006. Polymer blends of epoxy resin and epoxidized natural rubber. Journal of Applied Polymer Science 102: 452-459.

Garlotta, D., Doane, W., Shogren, R., Lawton, J. & Willett, J.L. 2003. Mechanical and thermal properties of starch-filled poly(D,L-lactic acid)/poly(hydroxy ester ether) biodegradable blends. Journal of Applied Polymer Science 88: 1775-1786.

Ho, C-H., Wang, C-H., Lin, C-I. & Lee, Y-D. 2008. Synthesis and characterization of TPO-PLA copolymer and its behavior as compatibilizer for PLA/TPO blends. Polymer 49: 3902-3910.

Huneault, M.A. & Hongbo, Li. 2007. Morphology and properties of compatibilized polylactide/thermoplastic starch blends. Polymer 48: 270-280.

Ishida, S., Nagasaki, R., Chino, K., Dong, T. & Inoue, Y. 2009. Toughening of poly(L-lactide) by melt blending with rubbers. Journal of Applied Polymer Science 113: 558-566.

Jacobsen, S., Fritz, H.G., Degée, Ph., Dubois, Ph. & Jerome, R. 1999. Polylactide (PLA)-a new way of production. Polymer Engineering & Science 39: 1311-1319.

Kiattanavith, N. 1986. Study of the oil-resistance of natural rubber. Bangkok: Mahidol University (Unpublished).

Mishra, J.K., Chang, Y-W. & Kim, D-K. 2007. Green thermoplastic elastomer based on polycaprolactone/ epoxidized natural rubber blend as a heat shrinkable material. Materials Letters 61: 3551-3554.

Mohanty, S., Nando, G.B., Vijayan, K. & Neelakanthan, N.R. 1996. Mechanical and dynamic mechanical properties of miscible blends of epoxidized natural rubber and poly(ethylene-co-acrylic acid). Polymer 37: 5387-5394.

Ruamcharoen, P., Umaree, S. & Ruamcharoen, J. 2011. Relationship between tensile properties and morphology of epoxy resin modified by epoxidised natural rubber. Journal of Materials Science and Engineering 5: 504-510.

Takeshi, S,. Kitagawa, K., Ishiaku, U.S. & Hamada, H. 2006. The effect of crosslinking on the mechanical properties of polylactic acid/polycaprolactone blends. Journal of Applied Polymer Science 101: 1816-1825.

Tanrattanakul, V., Sungthong, N. & Raksa, P. 2008. Rubber toughening of nylon 6 with epoxidized natural rubber. Polymer Testing 27: 794-800.

Yew, G.H., Mohd Yusof, A.M., Mohd Ishak, Z.A. & Ishiaku, U.S. 2005. Water absorption and enzymatic degradation of poly(lactic acid)/rice starch composites. Polymer Degradation and Stability 90: 488-500.

*Pengarang untuk surat-menyurat; email: mat.uzir@cheme.utm.my