Curing Characteristics and Physical Properties of Natural Rubber Composites Using Modified Clay Filler

Abstract

The differences in the curing characteristics and physical properties of natural rubber samples using clay and modified clay as fillers were studied. After the clay was modified with dodecylamine, the rubber milling process was conducted at a temperature of 65-70 o C to obtain the natural rubber compound. The content of clay and modified clay in the natural rubber was approximately 15 phr. A curing test at 150 o C was performed, and then the physical properties were tested. The results of the physical properties test showed a significant increase in the tensile strength, from 16.3 to 25 MPa, a change in hardness from 43 to 54 Shore A, a change in modulus of 300% from 1.6 to 4.6 MPa, a change in tear strength from 29.3 to 40.2 kN/m, and a change in compression set from 25.75% to 30.57% due to the use of modified clay compared to the sample with unmodified clay. However, some physical properties-such as elongation at break, from 720% to 600%-decreased dramatically. Smax increased sharply, from 7.05 to 11.45 kg-cm, while optimum cure and scorch time decreased sharply, from 11.23 to 6.43 minutes and from 6.35 to 2.38 minutes, respectively. FTIR and XRD analyses showed evidence of clay modification. Similarly, the AFM and SEM analyses of clay surfaces and the dispersion of the clay in the rubber showed that the dispersion of the modified clay in the rubber was better than that of unmodified clay. The TA/DTA analysis also supported the above explanation, particularly for the changes in curing characteristics and physical properties.

An Experimental Study of the Effect of Load and Moving Speed on Free Rotating Rubber Contact using Fluorescence Microscopy

“…This result was reported by Hasan et al (2020) in their study about the properties of tire rubber by modifying the clay filler of tires.…”

Physical Properties Investigations of Natural Rubber Composites Using Cetyltrimethylammonium Bromide (CTAB) as Modifier of Local Clay Filler

“…Revised 20 October 2023 Accepted 8 December 2023 hybrid filler between carbon black and lignin (Bahl et al, 2014) and mixing carbon black with calcium carbonate, soy protein, and biochar (Peterson, 2022). Researchers have paid much attention to use natural materials, such as clay, as filler (Hasan et al, 2020). There are many clay deposits in nature, one of which is found in the Bukit Asam coal mine area, in Indonesia.…”