Morphologies of Natural Rubber/Gelatinized Starch and Mineral Clay Composite

Abstract

Morphologies of natural rubber/ cassava starch and montmorillonite clay composite were studied. Composites were prepared in a latex state and subsequently cast into films. It was found that starch dispersed at molecular level in rubber matrix in amorphous (gel) state. The tensile fracture surface of composites as revealed by scanning electron microscope (SEM) showed no trace of starch granules. Microstructural characterization of clay dispersed in rubber matrix using X-ray diffraction technique (XRD) revealed an absence of diffraction peak originated from the orderly stacked layers of clay. This suggested that the primary clay particles were dispersed into individual layers. The dispersed clay platelets provided more surface area for the rubber and starch interactions which resulted in better reinforcing and improved mechanical properties namely increased tensile strength, modulus, toughness, tear strength and hardness while sacrificing the ultimate elongation, comparing to a neat rubber.