Carbon nanotubes (CNTs) are known to have remarkable mechanical and electrical properties. One of those properties is piezoresistance which makes them suitable to be used in the field of strain sensing. Multi-walled nanotubes (MWNTs) were incorporated in low-density polyethylene (LDPE) matrix to form composite film sensors with different concentrations of 1, 2, 3.5, 5, 6.5, and 8 weight%. The fabrication of such composite was carried out using solid-state mixing, followed by melt blending process. Both extrusion and compression molding processes were used where compression showed more promising results in terms of electrical conductivity. Two types of molds were examined in compression molding, namely flash type mold and a positive type mold. The positive type mold showed better control over process parameters. Furthermore two types of multi-walled carbon nanotubes of different aspect ratios were investigated using the positive type mold to examine their effect on the composite conductivity. The ones with the higher aspect ratio showed much higher conductivity. Strain sensitivity measurements were carried out on composite film samples at percolation threshold and beyond and gauge factors were obtained which showed significantly higher sensitivity than that of conventional strain gauges.


Mechanical Engineering Department

Degree Name

MS in Mechanical Engineering

Graduation Date


Submission Date

January 2012

First Advisor

Esawi, Amal

Second Advisor

Arafa, Mustafa



Document Type

Master's Thesis

Library of Congress Subject Heading 1


Library of Congress Subject Heading 2

nostructured materials.


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Institutional Review Board (IRB) Approval

Not necessary for this item


It is a pleasure to thank those who made this thesis possible. I especially want to thank my advisers Dr. Amal Esawi and Dr. Mustafa Arafa for their help and guidance during the research. Special thanks to Eng. Rami Wasfi, Eng. Ehab Salama, Eng. Hady Hussein, Eng. Ahmed Abdel Gawad, and Mr. Essam Aziz for their help with different samples testing and alyses at the different stages of this research. Also, thanks are due to Dr. Hosny Omar, Professor at the Physics department, for his helpful advice and fruitful discussions. I would like as well to thank the Science and Technology Research Center (STRC) for the fincial help and support.