Acoustic Properties of Polyurethane Composition Reinforced with Carbon Nanotubes and Silicon Oxide Nano-powder

Available online at www.sciencedirect.com

ScienceDirect Physics Procedia 70 (2015) 699 – 702

2015 International Congress on Ultrasonics, 2015 ICU Metz

Acoustic Properties of Polyurethane Composition Reinforced with Carbon Nanotubes and Silicon Oxide Nano-powder Wasim A. Orfali* Architectural Engineering Department, College of Engineering, Taibah University, P.O. Box 344, Al-Madina Al Munawara, Kingdom of Saudi Arabia

Abstract

This article demonstrates the acoustic properties of added small amount of carbon-nanotube and siliconoxide nano powder (S-type, P-Type) to the host material polyurethane composition. By adding CNT and/or nano-silica in the form of powder at different concentrations up to 2% within the PU composition to improve the sound absorption were investigated in the frequency range up to 1600Hz. Sound transmission loss measurement of the samples were determined using large impedance tube. The tests showed that addition of 0.2 wt.% Silicon Oxide Nano-powder and 0.35 wt.% carbon nanotube to polyurethane composition improved sound transmissions loss (Sound Absorption) up to 80 dB than that of pure polyurethane foam sample. Keywords: Acoustic properties, Sound transmission loss, carbon nanotube, nano-silica;I-INCE Classification of Subjects Number(s): 51.4 © Published by Elsevier B.V. B.V. This is an open access article under the CC BY-NC-ND license ©2015 2015The TheAuthors. Authors. Published by Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Scientific Committee of 2015 ICU Metz. Peer-review under responsibility of the Scientific Committee of ICU 2015 Keywords: Acoustic properties, Sound transmission loss, carbon nanotube, nano-silica;I-INCE Classification of Subjects Number(s)

* Corresponding author. Tel.: +966-014-8460008; fax: +966-014-8474698. E-mail address: [email protected]

1875-3892 © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Scientific Committee of ICU 2015 doi:10.1016/j.phpro.2015.08.091

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1. INTRODUCTION Polyurethane foam is one of the most common polymer foams used in everyday life and applications. Polyurethane foams have cellular structure which improves sound absorbing and insulating properties [1]. There are few studies in the literature regarding the use of nanoclay [6], titania nanoparticles [7,8] multi-walled carbon nanotubes (MWNTs) reinforced polyurethane (PU) for giving rise to considerable improvement in polyurethane foam sound absorption. Especially CNTs having promising mechanical properties were used as a filler to improve sound absorption properties of the PU-based composites [2]. Additionally, nano-silica have been widely introduced into polymers to improve the heat resistance, radiation resistance, mechanical and electrical properties of polymer materials[3,4]. Nano-silica compositions have remarkable improvement in materials properties. Nano-silica has the features of small particle size, narrow particle size distribution, porous, large surface area [9]. 2. MATERIALS AND METHODS In this study, CNTs and Silicon Oxide Nanopowder were added to the polyol and isocyante composition to improve sound insulation efficiency. PU foam mixtures were prepared at different weight ratios (0.2%, 0.5%, 1%) of silicon oxide nano-powder, (0.2%, 0.5%, 1%) of silicon oxide hollow Micron powder and CNTs combination such as:((PU/Nano-silica P-type (0.5wt%)+ PU/CNTs (1wt%)), (PU/Nano-silica S-type (0.5wt%)+ PU/CNTs (1wt%)) and (PU/Nano-silica P-type (0.5wt%)+ PU/Nano-silica S-type (0.5wt%)). Finally, twelve different type of (3 CNTs, 3 Nano-silica P-type, 3 Nano-Silica S-type, 3 Mixed of CNTs and Nano-Silica) reinforced PU foams were produced. 3. RESULTS AND DISCUSSION

Sound TL (db)

Transmission loss measurement was performed using Brüel&Kjær Acoustic measurement tube. Twelve samples were performed at least two times and averaged to get the final result. Transmission loss measurements of the PU-composition are shown below. Increasing amount of nano-silica P-Type content has a better sound insulation comparing the pure PU foam up to 100 Hz. 80

Pure PU

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PU/Nano-Silica P-type (0.2wt%) PU/Nano-Silica P-type (0.5wt%) PU/Nano-Silica P-type (1wt%)

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Figure 1.PU and PU/Nano-Silica(P-Type) composites (0–600 Hz).

Sound TL (db)

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Pure PU PU/Nano-Silica S-type (0.2wt%) PU/Nano-Silica S-type (0.5wt%)

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PU/Nano-Silica S-type (1wt%)

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Figure 2.PU and PU/Nano-Silica(S-Type) composites (0–400 Hz).

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0.35wt% and 0.7wt% of CNTs content has a better sound insulation comparing the pure PU foam between 30-70 db. Surprisingly, addition 2 wt% of CNTs has a poor effect comparing the pure PU foam. The reason is that, increasing

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the amount of CNTs cause the prevent interaction of polyol and isocyanate with each other effectively. Besides, especially all CNTs caused to bubble on the inner surface of the PU foams which could lead the decrease of sound absorption efficiency. The addition of 0.7wt% CNTs leads to a significant increase of sound transmission loss at 3040 Hz.

Sound TL

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Pure PU PU/CNTs (0.35wt%)

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PU/CNTs (2wt%)

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Figure 3.PU and PU/CNTs composites (0–400 Hz).

Sound TL (db)

At the lower frequency level (0-200) it was observed that 0.5 wt% Nano-silica S-type and P-type has better sound absorption ratio. Nano-Silica and CNTs were added together into the polyurethane composition. The test showed that at the mid frequency level (200 to 700 Hz) the sound absorption ratio is the best for pure polyurethane samples. 80

Pure PU

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PU/Nano-silica P-type (0.5wt%)+ PU/CNTs (1wt%)

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PU/Nano-silica S-type (0.5wt%)+ PU/CNTs (1wt%)

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Frequency (Hz)

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PU/Nano-silica P-type (0.5wt%)+ PU/Nano-silica S1 200 type (0.5wt%) 1 400 1 600

Figure 4.PU, PU/Nano-Silica and PU/CNTs composites (0–1600 Hz).

Sound TL (db)

It was observed that at the mid frequency level, the Pure PU has better sound insulation properties. On the contrary, between 800-1000 Hz the Pure PU foam has the worst sound insulation properties. 80

Pure PU

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PU/Nano-Silica P-type (0.2wt%) PU/Nano-Silica S-type (0.2wt%)

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PU/CNTs (0.35wt%)

20 PU/Nano-silica P-type (0.5wt%)+ PU/CNTs (1wt%)

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Figure 5. PU, PU/Nano-Silica (P-Type, S-Type) and PU/CNTs (0-1600 Hz)

Including 0.2 wt% of nano-silica P-type leads to a significant improvement at the 22-32 Hz between 40 to 150 Hz, sound absorption characteristics of 0.2 wt% Nano-silica S-type, P-type and 0.35 wt% CNTs are substantially same acoustic properties. From 0 Hz to 20 Hz, 0.2 wt% Nano-silica P-type has much more better sound absorption ratio than Nano-silica S-type.

Wasim A. Orfali / Physics Procedia 70 (2015) 699 – 702

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Pure PU

Sound TL (db)

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PU/Nano-Silica P-type (0.2wt%) PU/Nano-Silica S-type (0.2wt%) PU/CNTs (0.35wt%)

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PU/Nano-silica P-type (0.5wt%)+ PU/CNTs (1wt%)

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Frequency (Hz)

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Figure 6.PU, PU/Nano-Silica (P-Type, S-Type) and PU/CNTs composites (0–160 Hz)

4. CONCLUSION In this study, effects of the addition small amount of CNTs and Nano-Silica into polyurethane foam on the sound absorption were investigated. Twelve samples at different weight ratios of CNT and Nano-Silica were developed and tested to determine their sound absorption properties. The tests showed that addition of 0.2 wt.% Silicon Oxide Nano-powder and 0.35 wt.% carbon nanotube to polyurethane composition improved sound transmissions loss up to 80 dB than that of pure polyurethane foam sample. Considering all of test samples,0.35wt% and 0.7wt% of CNTs content has a better sound insulation comparing the pure PU foam between 30-70 Db. Surprisingly, addition of 2 wt% CNTs has a poor effect than the pure PU foam. One reason is that, increasing the amount of CNTs cause the prevent interaction of polyol and isocyanate with each other effectively. Including 0.2 wt% of Nano-Silica P-type leads to a significant improvement at the 22-32 Hz. In addition to this, nano-silica P-type has much better sound absorption ratio than nano-silica S-type substantially all along the frequency ranges. 5. ACKNOWLEDGEMENT We would like to give special thanks to Levent Trabzon, Professor in Istanbul Technical University and Raghied Mohammed Helmy Atta, Professor in Taibah University, for there guidance and help in the summer time. 6. REFERENCES 1 . http://www.eurofoam.hu/Application/technical-foam-department/audiotec-absorption/2/ 2. Carbon nanotube-reinforced polyurethane composite fibers Wei Chena, b, XiaomingTaoa, YuyangLiua 3. G.D. Chen, S.X. Zhou, G.X. Gu, L.M. Wu, Modi¿cation of colloidal silica on themechanical properties of acrylic based polyurethane/silica composites, Colloids Surf. A: Physicochem. Eng. Aspects 296 (2007) 29– 36. 4. G. Leder, T. Ladwig, V. Valter, S. Frahn, J. Meyer, New effects of fumed silica inmodern coatings, Prog. Org. Coat. 45 (2002) 139–144. 6. Cao X et al. Polyurethane/clay nanocomposites foams: processing, structure and properties. Polymer 2005;46(3):775–83. 7. Mahfuz H et al. Response of sandwich composites with nanophased cores under Àexural loading. Compos B Eng 2004;35(6–8):543–50. 8. Mahfuz H et al. Fabrication, synthesis and mechanical characterization of nanoparticles infused polyurethane foams. Compos A ApplSciManuf 2004;35(4):453–60. 9. http://www.nanoparticles-microspheres.com/Products/Nano-SiO2.html