Effect of Silane Treatment Methods on Physical Properties of Rice Husk Flour/Natural Rubber Composites

Ladawan Srisuwan,Kasama Jarukumjorn,Nitinat Suppakarn

doi:10.1155/2018/4583974

Ladawan Srisuwan, Kasama Jarukumjorn + Show 1 more

Open Access

https://doi.org/10.1155/2018/4583974

Copy DOI

Abstract

In this study, the effect of silane treatment methods on cure characteristics and mechanical, dynamic mechanical, and morphological properties of rice husk flour (RHF)/natural rubber (NR) composites was investigated. The RHF surface was pretreated with alkali solution and then treated with bis(triethoxysilylpropyl) tetrasulfide (TESPT) solution using the unwashing silane treatment method and washing silane treatment method. The expected difference between these two methods was the silane layers presented on the RHF surface. Unwashed TESPT-treated RHF (UW-ST) and washed TESPT-treated RHF (W-ST) were incorporated into NR to prepare RHF/NR composites. The TESPT molecules deposited on UW-ST and W-ST surfaces were confirmed by the additional peaks appeared in the FTIR spectra of UW-ST and W-ST. In addition, the decrement of decomposition temperatures and the changes in the residue amounts of UW-ST and W-ST proved the removal of the physisorbed silane layers after washing. The presence of TESPT molecules on the RHF surface enhanced compatibility and adhesion between RHF and NR matrix. This was confirmed by SEM micrographs of both UW-ST/NR and W-ST/NR composites. This result was also supported by the improvement of the mechanical and the dynamic mechanical properties of these two composites. According to mechanical properties of the NR composites, the washing silane treatment method was more effective than the unwashing silane treatment method for compatibility improvement between RHF and NR. The modulus, tensile strength, and tear strength of W-ST/NR composites can be enhanced without deterioration of their elongation at break.

Highlights

Natural rubber (NR) is one of the major agricultural products of ailand
According to mechanical properties of the NR composites containing an rice husk flour (RHF) of 30 phr, the results indicated that the washing silane treatment method was a more effective method than the unwashing silane treatment method for compatibility improvement between RHF and NR
Conclusions e RHF surface was treated with TESPT solution, a silane coupling agent with four sulphur atoms in its structure, using unwashing and washing treatment methods. e TESPT molecules deposited on the Unwashed TESPT-treated RHF (UW-ST) and washed TESPT-treated RHF (W-ST) surfaces were confirmed by the appearance of C–H stretching and Si–O–Si stretching of TESPT in the Fourier transform infrared spectrometer (FTIR) spectra of the treated RHF

Summary

Introduction

Natural rubber (NR) is one of the major agricultural products of ailand. NR has been used in several industrial applications, for example, tire, hose, belting, and bridge bearing due to its attractive properties, that is, high tensile strength, high tear strength, and high elasticity. Ese fillers have advantages over the conventional fillers typically used in NR industries, which are carbon black and silica, in the views of renewability, biodegradability, environmental safety, low density, and low cost [3]. They possess interesting properties such as high specific strength and high stiffness. Among those natural fillers, rice husk flour (RHF) is attractive since it is abundantly available in ailand as a by-product from the rice milling process.

Objectives

Results

Conclusion