Effect of Modified Silica Fume Using MPTMS for the Enhanced EPDM Foam Insulation.

Rudeerat Suntako

doi:10.3390/polym13172996

Abstract

Silica fume (SF) is a by-product from the production of silicon metal, which has a relatively high silica concentration. The surface modified silica fume (mSF) is treated with (3-mercaptopropyl) trimethoxysilane (MPTMS) as filler in ethylene propylene diene monomer (EPDM) foam. The FTIR spectra of mSF clearly indicated that MPTMS can be successfully bonded to the SF surface. The reinforcing efficiency of mSF-filled EPDM foam insulation indicated that the mechanical properties such as hardness, tensile strength, modulus, and compression set enhanced higher than in case of SF and calcium carbonate. While the cure characteristics such as the maximum torque (MH), the minimum torque (ML) and the differential torque (MH-ML) are increasing in proportion to increasing filler contents, mainly with mSF. For the cure behavior, the mSF-filled EPDM foam insulation showed the fastest cure time (tc90) and scorch time (ts2) due to reduced accelerator adsorption. Whereas, the calcium carbonate-filled EPDM foam insulation increased the cure time (tc90) and scorch time (ts2), therefore, it also prevents compound scorching. The results indicated that the mSF with MPTMS can be used as an alternative filler for EPDM foam insulation.

Highlights

ethylene propylene diene monomer (EPDM) foam insulation is a flexible and low density and light weight product
The silica fume (SF) surface treatment by MPTMS can be identified that the peak at 810 cm−1 is due to the stretching vibration of the siloxane (Si–O–Si) bonding [7,28]
This clearly indicated that MPTMS can be successfully treated onto the SF surface, which was confirmed by comparing the Fourier transform infrared spectroscopy (FTIR) spectra of SF and modified silica fume (mSF)

Summary

Introduction

EPDM foam insulation is a flexible and low density and light weight product. This product is widely used to save energy and prevent condensation problems with chilled water and refrigeration systems. Organosilane coupling agents such as (3-mercaptopropyl) trimethoxysilane (MPTMS) [10,20], bis-(3-triethoxysilylpropyl) tetrasulfane (Si-69) [21,22,23,24,25,26], 3-thiocyanatopropyl triethoxy silane (Si-264) [25], Cetyltrimethyl ammonium bromide (CTAB) [22] and 3-octanoylthio-1-propyltriethoxysilane (NXT) [27] are used to modify the surface of filler which is improve its reinforcing as well as processing characteristics. It offers promising potential as an alternative filler for EPDM foam insulation. This study focuses on its rubber mechanical properties, which have not been reported elsewhere

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