Preparation, characterization and properties of organoclay filled natural rubber nanocomposites

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Date
2009
Authors
Raja Nazri, Raja Nazrul Hakim
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Abstract
The research on natural rubber (NR) nanocomposites using “Standard Malaysian Rubber” (SMR L) grade with organophilic montmorillonite clays was undertaken. SMR L nanocomposites were prepared by melt mixing on a two roll mill and cured using a sulphur conventional vulcanization system. Silica/NR nanocomposites were used as comparison. The effects of organoclay with different filler loading up to 10 phr on curing characteristics, mechanical properties, hardness, swelling behaviour and thermal stability of SMR L nanocomposites were studied. Both scorch time and cure time were reduced and the maximum torque increased with the increased loading of organoclay in SMR L nanocomposites. Silica filled NR nanocomposites exhibit longer scorch time, cure time and decreased maximum torque values. The tensile strength of NR nanocomposites increased up to 8 phr loading and then decreased with increasing organoclay loading. Elongation at break continuously increased with increased organoclay loading. Comparison is made with silica filled NR nanocomposites and it shows that the tensile strength and elongation at break of silica filled NR nanocomposites are much inferior than organoclay filled NR nanocomposites. ENR 50 nanocomposites exhibit shorter scorch and cure time when compared to SMR L nanocomposites. The tensile strength of both the nanocomposites increased to an optimum of 8 phr organoclay loading. When organoclay loading was increased, tensile strength drops slightly. When compared between the two nanocomposites, ENR 50 nanocomposites have lower value of elongation at break. The effect of stearic acid on properties of natural rubber nanocomposites was studied. The optimum organoclay content was fixed at 8 phr. SMR L nanocomposites display longer scorch and cure time with the increased amount of stearic acid. Tensile strength increased to an optimum of 7.5 phr and then drops slightly with increased stearic acid loading. However, elongation at break increased with increased loading of stearic acid. The effect of increased organoclay loading with the presence of maleated natural rubber (MANR) in SMR L nanocomposites was studied. MANR content was capped at 6 phr. Shorter scorch and cure time was achieved with the presence of MANR when compared to SMR L nanocomposites without MANR. Tensile strength increased to an optimum of 8 phr before it reduced slightly. Improvements of mechanical properties such as elongation at break and tensile modulus was also observed with MANR. Thermal stability of SMR L nanocomposites with MANR is excellent. Organoclay filled SMR L nanocomposites are then subjected to X – ray diffraction test (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) test. It has been proven that organoclays intercalated and exfoliated within SMR L nanocomposites.
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Master
Keywords
Materials and Mineral Resources Engineering , Organoclay , Natural rubber nanocomposites
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