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An Investigation of Polymeric Nanocomposite: Surface Functionalization and Nanofiller Effect

Zhanhu Guo1, Xiaofeng Liang1, Brian Shedd1, Roberto Scaffaro2, and H. Thomas Hahn1. (1) Multifunctional Composite Lab, Mechanical & Aerospace Engineering Department, University of California at Los Angeles, Los Angeles, CA 90095, (2) Department of Chemical Engineering and Materials, University of Palermo, Viale delle Scienze, Ed. 6, Palermo, 90128, Italy

Polymeric nanocomposites embedded with inorganic nanoparticles have attracted much interest due to their unique mechanical, electric, magnetic and optical properties [1-4] and the wide potential applications such as in high-sensitivity chemical gas sensors [5], electromagnetic wave absorbers and solar cells. Fabricating high quality nanocomposites becomes a challenge due to the difficulty in producing uniformly dispersed nanoparticles in polymer matrix and the poor interaction between nanoparticles and matrix. Poor dispersion and the weak bonding between nanoparticles and matrix result in a deleterious effect on the mechanical properties of the nanocomposite. Surface functionalization of the nanoparticles with a surfactant or coupling agent is subsequently important not only to stabilize the nanoparticles but also to render the nanoparticles compatible with the polymer.

In this project, a bi-functional surfactant, (3-methacryloxypropyl) trimethoxysilane (MPS), was used to functionalize the nanoparticles. Three different ceramic nanoparticle (alumina, zinc oxide and copper oxide) systems were studied. The chemical covalent bond between the nanoparticle and MPS was justified by FT-IR spectra, and TGA analysis. The functionalized nanoparticles formed a unity with the vinyl ester resin through the nanoparticle functionalization with the MPS. Tensile tests revealed strengthened mechanical properties in the functionalized alumina nanoparticles filled nanocomposite. Enhanced photoluminescence was observed in the functionalized zinc oxide nanoparticle filled nanocomposite. The nanofiller materials were observed to have a significant effect on the curing process and thus the thermal properties. The high-quality nanocomposites were fabricated at 85 oC in both alumina and zinc oxide nanoparticle-vinyl ester resin systems. However, soft nanocomposites were formed in the copper oxide system at 85 oC, hard nanocomposites were obtained by curing at room temperature following by a a postcuring at 85 oC. In addition, little change in the thermal degradation of the nanocomposites was observed in the nanocomposite filled with alumina nanoparticles. However, zinc oxide filler exhibited some deleterious effect on the thermal degradation of the nanocomposites; and copper oxide nanoparticles had a significant effect on the decreased thermal degradation of the nanocomposite. The detailed effect of the filler materials and the surface modification on the physicochemical properties of the nanocomposite will be presented. This project was support by Air Force Office of Scientific Research through AFOSR Grant FA9550-05-1-0138.

References:

[1] V. Yong and H. T. Hahn, Nanotechnology, 2004, 15, 1338

[2] G. Sandi, H. Joachin, R. Kizilel, S. Seifert, and K. A. Carrado, Chem. Mater., 2003, 15, 838.

[3] Z. Guo, T. Pereira, O. Choi, Y. Wang and H. T. Hahn, J. Mater. Chem., 2006, 16, 2800.

[4] Z. Guo, L. Henry, V. Palshin, and E. J. Podlaha, J. Mater. Chem., 2006, 16, 1772.

[5] H. Tang, M. Yan, X. Ma, H. Zhang, M. Wang, and D. Yang, Sensors and Actuators, 2006, B113, 324.



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