Nondestructive testing of defects in adhesive joints

Structure property relationship studies of melt spun carbon
nanotubes filled polypropylene fiber
Pankaj B. Tambe a* , Arup R. Bhattacharyya a# , Srikanth Kamath a , Ajit R. Kulkarni a ,
T.V. Sreekumar b b
, Kingsuk Mukhopadhyay and
Anurag Srivastav b
a Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology
Bombay, Powai, Mumbai 400076, India
b Defence Materials and Stores Research and Development Establishment (DMSRDE), DRDO,
Kanpur 208013,India
Email: arupranjan@iitb.ac.in
Abstract
Two different types of multiwalled carbon nanotubes (MWNT) were utilized in order to
understand the effect of different types of MWNT in enhancing mechanical properties of the melt
spun MWNT filled polypropylene composite fibers. It was found that MWNT synthesized in
DMSRDE were found to be superior over NC 3100 procured from Nanocyl, CA, Belgium in
achieving high modulus and tenacity of PP/MWNT composite fibers. Herman’s orientation factor
of (110) PP plane and MWNT along the composite fiber axis were also calculated and it was
found that MWNT prepared in DMSRDE found to exhibit higher orientation over NC 3100
MWNT.
1. Introduction
Polypropylene (PP) is one of the major polymeric fiber materials of future in view of its
impressive consumption in the past decade. However, PP fiber needs reinforcement in order to
achieve high stiffness and strength for engineering applications. Since the discovery of carbon
nanotubes (CNT) by Iijima [1], CNT have emerged as a potential candidate as reinforcing filler
in polymer based composites due to their unparallel mechanical, electrical and thermal properties.
Melt spinning process is one of the most common and viable route to produce polymer fiber. The
formation of fibers involves four stages: a) melting the polymer, b) extrusion of melt through
spinneret, c) cooling along spin line and winding the resulting fiber on a roll and d) the resulting
fiber post drawn to a maximum possible draw ratio.
Several studies have been carried out on crystallization, orientation and mechanical
properties of melt-blended PP/single wall carbon nanotube (SWNT) [2] and PP/ multiwall carbon
nanotube (MWNT) [3] composites fiber. In addition flourinated SWNT [4] and benzoyl per oxide
initiated functionalization of SWNT [5] to PP chain were also utilized in order to improve the
exfoliation and interfacial adhesion of SWNT with PP chain in order to improve the mechanical
properties of composite fiber.
The aim of this work is to evaluate the effect of two different types of MWNT on the
structure property of PP/MWNT composite fiber. Oriented structure of PP crystal plane and
MWNT along the fiber axis are quantified as per Herman’s orientation factor. The effect of
orientation of PP crystal plane and MWNT are correlated with the mechanical properties of
PP/MWNT composite fiber.