Effect of Lignin Mixing Method on Physical and Mechanical Properties of Wood Flour- Polypropylene Composites

Document Type : Research Paper

Authors

Abstract

In this study, the effect of two lignin mixing methods on physical and mechanical properties of wood flour- polypropylene composites was investigated. Kraft lignin was extracted from black liquor by acidic method and was mixed with wood flour by physical and chemical methods with ratios of 2, 5 and 10 percent (based on wood flour dry weight). The composites were produced by hot press method after mixing of wood flour, lignin and polypropylene at presence or without MAPP. The physical and mechanical properties of prepared samples were measured according to standard methods. In general, the results showed that adding lignin to composites decreased water absorption in both methods. Also increasing lignin from 2 to 10 percent increased impact strength of composites with or without MAPP. Flexural strength of the composites differed depending on mixing method. Increasing of lignin decreased flexural strength of the composites without MAPP in the physical mixing method where as in chemical mixing method it was increased. It is to be noted that the composites with 5 percent lignin, made with physical mixing method and with MAPP exhibited higher flexural strength than other composites.

Keywords


1.Sjostrom, E., 2009, Wood chemistry: Fundamentals and applications, translated by Mirshokraie, S.A., Aeejh publication, pp.155-160.
2. Younesi kurdkheili, H., Kazemi Najafi, S., 2009, Effect of Caspian sea and Persian gulf waters on physical and mechanical wood-polymer composites, 11th Marine industries conferences, 10-12 Nov., Kish Island.
3. Kazemi Najafi, S., Younesi kurdkheili, H., Nasiri, R., Effect of sea water on coupling agent performance in water absorption behavior of wood flour-polypropylene composites, Journal of the iranian natural resources (In press).
4.American Society for Testing and Materials (ASTM), ASTM D-7031-04, West          Conshohocken, PA, 2004.
5. American society for testing and material, ASTM D256-90b, West Conshohocken, Pa. USA.1990.
6. Andrzej, K., and Bledzki, F.O. 2004 Creep and impact properties of wood fibre–polypropylene composites: influence of temperature and moisture content, Composites Science and Technology. 64 693–700.
7. Behrooz R, Younesi Kordkheili H., and Jalilvand M. 2009. Using wastes of OCC paper recycling mills. Proceedings of 11th international conferences on environmental science and technology. Greece, 3-5 September.
8. Chow, C.P.L., Xing, X.S., and Li R.K.Y. 2007. Moisture absorption studies of sisal fiber reinforced polypropylene composites, Journal of Composites Part B. 67: 306-313.
9.European Standard. 1993. Determination of modulus of elasticity in bending and        bending strength. Din En 310.
10. Lin, Y.S., and Dence, C.V.1992. Methods in lignin chemistry Springer-Verlag (Berlin, New York). pp 578
11.Lu, Z., Wu Q., and Mc Nabb S., 2000: Chemical coupling in wood fiber and polymer composites: A review of coupling agents and treatments. Wood and Fiber Science, 32 (1): 88-104.
12. Rozman, H.D., Tan K.W., Kumar R.N., Abubakar A., Ishak Mohd., and Ismail H., 2000: The effect of lignin as a compatibilizers on the physical properties of coconut fiber-polypropylene composites. European Polymer Journal, 36(7 (: 1483-1494.
13. Sain, M., Suhara, P., Law, S. and Bloullooux, A., 2005. Interface modeification and mechanical properties of natural fiber-polyolefin composite products. Journal of Reinforced Plastics and Composites, 24(2): 121-130.
14. Standard testing methods for melt flow rates of thermoplastics by extrusion plastomer.  Annual Book of ASTM Standard, D1238-98, 1998.
15. Toriz,G., Denes, F., and Young, R. A. 2002. Lignin-polypropylene composites. Part 1: Composites from unmodified lignin and polypropylene. Journal of Polymer Composites, 23 (5).
16. Timothy, A., Vipul, S., Meng-jiu, C., and John, J.M., 2003. Graft copolymers of lignin as hydrophobic agents for plastic (Wood-Filled) composites. Journal of Applied Polymer Science, 89: 1266–1276.