IJET: ISSN 1812-7711, Volume 8 Issue 2 2011 786 International J. Eng. Tech 8(2):786-792, June 2011 A publication of “G-Science Implementation & publication” website: www.gscience.net or www.gurpukur.com PHYSICO-MECHANICAL PROPERTIES OF SHOCK WAVE TREATED JUTE FIBER REINFORCED COMPOSITE MATERIALS G. M. SHAFIUR RAHMAN 1 , MUHAMMAD ABDULLAH AL MAMUN 2 and SHIGERU ITOH 3 ABSTRACT One of the main disadvantages of Natural Fiber Reinforced Composites (NFRP) is the adhesion between fiber and polymer matri- and relatively high moisture absorption. To improve the adhesion between the matrix and fiber, the fiber surface can be modified using the chemical, physical and radiation methods. In this work, newly a novel physical method underwater shock wave treatment for surface modification of jute fiber is developed for composite fabrication. This work also examines the effect of fiber treatments using underwater shock wave on mechanical properties and absorption behavior of fabricated jute fiber reinforced thermosetting polyester composite. The studies of physico-mechanical properties of show that the shockwave treated jute fiber reinforced composite exhibits better hydrophobic property than that untreated one. On the other hand mechanical properties of shock wave treated jute fiber reinforced composite were not found satisfactory level due to formation of micro cracks on the fibers surface after treatment. The study was conducted at the Tang ail district of Bangladesh during December 2009 to January 2010. Keywords: Water absorption, Composite fabrication, Reinforced composite and Underwater explosion shock testing INTRODUCTION In recent years, the natural fiber reinforced composite has gained substantial importance as a potential low cost structural material due to their low cost, low density, light weight, good mechanical properties, renewability and biodegradability (Bolton, 1995 and Dakal et al., 2007). There is a large group of composites prepared from polymeric matrices reinforced with vegetable /natural fibers (Mohanty and Mistra, 1995; Mohanty et al., 2002a and Mohanty et al., 2002b). New environmental legislation as well as consumer pressure has forced manufacturing industries (particularly automotive, construction and packaging) to search for a new materials that can substitute for conventional non-renewable reinforcing materials such as glass fiber (Bledzki and Gassan, 1999). However, the main disadvantages of natural fiber reinforced composites are the compatibility between fiber and polymer matrix, and relatively high moisture absorption. All polymer composites absorb moisture in humid atmosphere and when immersed in water. The effect of moisture leads are the degradation of fiber matrix interface region creating poor stress transfer efficiencies resulting in a reduction of mechanical and dimensional properties (Yang et al., 1996). The high strength jute fibers have not been intensively exploited in reinforced composites. This occurs, at least partially, because they are hygroscopic and their low wettability by resins. This characteristics result mainly from the presence of hydroxyl groups and other polar groups in several constituents of the fiber (Gassan and Blendzki, 1997). One of the main concerns for the use of natural fiber reinforced composite materials is their susceptibility to moisture and the effect on physical, mechanical and thermal properties (Thwe and Liao, 2002). Moisture absorption can also result in swelling of the fibers and concerns at the dimensional stability of the natural fiber composite cannot be ignored. It is difficult to entirely eliminate the absorption moisture by the fiber without using expensive surface barriers on the composite surface. Rigid fiber-matrix bonding can decrease the rate and amount of moisture by the fiber. The incompatibility between the hydrophilic natural fiber and hydrophobic thermoplastic and thermoset matrices requiring appropriate use of physical and chemical treatment to enhance the adhesion between the fiber and the matrix (Gassan and Cutowski, 2000). Composites of hydrophilic natural fiber with hydrophobic or non polar polymer matrix result in poor mechanical properties compared to pure polymer. The hydrophilic nature of natural fiber adversely affects adhesion to a hydrophobic matrix and as a result, it may cause a loss of strength. In order to overcome the above describes problems, it is strongly recommended that the fiber surface has to be modified in order to promote adhesion (Rahman, 2009). 1 Assistant Professor, 2 MSc Student (Thesis), Department of Materials Science and Engineering, Rajshai University, Rajshahi, Bangladesh, 3 Professor, Shockwave and Condensed Matter Research Center, Kumamoto University, Japan.