Table 1 illustrates the raw materials used in this research. Maleated natural rubber (MNR) was prepared inhouse by blending the rubber air-dried sheet (manufactured by Khuan Pun Tae Farmer Co-operation, Phattaluang, Thailand) with 8 phr of maleic anhydride at 150 C using an internal mixer (Brabender Plasticorder, model PLE331, Brabender OHG Duisburg, Germany) at a rotor speed of 60 rpm.