EFFECT OF POLY(D-LACTIC ACID) ON PHYSICAL PROPERTIES OF POLY(LACTIC ACID)/NATURAL RUBBER BLENDS
Abstract
In this study, poly(lactic acid) (PLA) was melt blended with a natural rubber (NR) at the ratios of 95/5, 90/10, 85/15, and 80/20 by weight. It was found that the impact strength and elongation at break of PLA/NR blends increased with increasing NR content up to 5 wt%.While tensile strength and Young’s modulus decreased. The most significant improvement in Izod impact strength and elongation at break was found for the blend containing 15 wt%NR. Therefore, PLA/NR at a ratio of 85/15 wt% was chosen to study the effect of poly(D-lactic acid) (PDLA) on mechanical properties and heat distortion temperatures (HDT)of PLA/NR blend. The amount of PDLA applied was 1, 3, and 5 percent by weight basedon PLA content in the blend. The results showed that impact strength and elongation at break of PLA/NR blend decreased with increasing amount of PDLA. However, the values were still higher than those of pure PLA. HDT of the blend with 1 wt% PDLA based onPLA content was improved in comparison to that of PLA/NR blend and pure PLA.
References
Bitinis, N., Verdejoa, R., Cassagnau, P., and Lopez-Manchadoa, M.A. (2011). Structure and propertiesof polylactide/natural rubber blends. Mater. Chem.Phys., 129(3):823-831.
Bitinis, N., Sanz, A., Nogales, A., Verdejoa, R., Lopez-Manchadoa, M.A., and Ezquerra, T.A. (2012).Deformation mechanisms in polylactic acid/naturalrubber/organoclay bionanocomposites as revealedby synchrotron X-ray scattering. Soft Matter.,8(34):8990-8997.
Brizzolara, D., Cantow, H.J., Diederichs, K., Keller, E.,and Domb, A.J. (1996). Mechanism of thestereocomplex formation between enantiomericpoly(lactide)s. Macromolecules, 29(1):191-197.
Ikada, Y., Jamshidi, K., Tsuji, H., and Hyon, S.H. (1987).Stereo complex formation between enantiomericpoly(lactides). Macromolecules, 20(4):904-906.
Juntuek, P., Ruksakulpiwat, C., Chumsamrong, P. andRuksakulpiwat, Y. (2011). Effect of glycidylmethacrylate-grafted natural rubber on physical properties of polylactic acid and natural rubberblends. J. Appl. Polym. Sci., 125(1):745–754.
Pongtanayut, K., Thongpin, C., and Santawitee, O. (2013).The effect of rubber on morphology, thermal properties and mechanical properties of PLA/NRand PLA/ENR blends. Energy Procedia., 34:888–897.
Tang, Z., Zhang, C., Liu, X., and Zhu, J. (2012). Thecrystallization behavior and mechanical properties of polylactic acid in the presence of a crystalnucleating agent. J. Appl. Polym. Sci., 125(2):1108–1115.
Tjong, S.C., Chen, J.S., and Liu, S.L. (1996). Structural properties and impact fracture behavior of injectionmolded blends of liquid crystalline copolyester and modified poly(phenylene oxide). Polymer Eng.Sci., 36(6):797-806.
Tsuji, H. and Ikada, Y. (1999). Stereo complex formation between enantiomeric poly(lactic acid)s. XI.Mechanical properties and morphology of solutioncastfilms. Polymer., 40(25):6699-6708.
Tsuji, H., Takai, H., and Saha, S.K. (2006). Isothermal andnon-isothermal crystallization behavior of poly(l-lactic acid): Effects of stereo complex as nucleating agent., Polymer., 47(11):3826–3837.
Sarasua, J.R., Arraiza, A.L., Balerdi, P., and Maiza, I.(2005). Crystallinity and mechanical properties ofoptically pure polylactides and their blends. Polym.Eng. Sci., 45(5):745-753.
Xu, C., Yuan, D., Fu, L., and Chen, Y. (2014). Physical blend of PLA/NR with co-continuous phase structure: Preparation, rheology property, mechanical properties and morphology. Polymer Testing.,37:94-101.
