Continuous fibre composites with a nanocomposite
matrix: Improvement of flexural and compressive strength
at elevated temperatures
D.P.N. Vlasveld
a,
*
, W. Daud
b
, H.E.N. Bersee
b
, S.J. Picken
a,
*
a
Nanostructured Materials, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands
b
Design and Production of Composite Structures, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 3,
P.O. Box 5058, 2600 GB Delft, The Netherlands
Received 19 May 2006; received in revised form 27 July 2006; accepted 27 September 2006
Abstract
Polymer layered silicate nanocomposites can improve the flexural and compressive strength of continuous fibre reinforced composites
by means of increasing the matrix modulus. A three-phase thermoplastic composite consisting of a main reinforcing phase of woven glass
fibres and a polyamide 6 (PA6) nanocomposite matrix was fabricated. Flexural testing of a conventional PA6 fibre composite has shown
a decrease of the flexural strength upon increasing temperature. This behaviour is associated with the decrease of the matrix modulus,
especially above T
g
. The nanocomposite used in this study has a modulus that is much higher than unfilled PA6, even above T
g
and after
moisture conditioning. The results showed that the fibre composites with a nanocomposite matrix have a more than 40% increased flex-
ural and compressive strength at elevated temperatures. This also means that the temperature at which the materials can be used is
increased by 40–50 °C. Therefore, by using a nanocomposite matrix the high temperature performance of fibre composites can be
improved without any change in processing conditions. The combination with other advantages of nanocomposites in areas such as bar-
rier properties, flammability and creep makes this a very attractive approach.
Ó 2006 Elsevier Ltd. All rights reserved.
Keywords: A. Polymer–matrix composites (PMCs); B. Strength; C. High-temperature properties; Nanocomposite
1. Introduction
Thermoplastic polymer fibre composites offer numerous
advantages over thermoset polymer composites, including
long shelf life of prepregs, zero emissions during processing
and the ability to reprocess and recycle. The advantages of
thermoplastic composites in processing have led to the
development of thermoplastic fibre composites in many dif-
ferent price- and performance classes. Thermoplastic poly-
mer composites are ideal material candidates for structures
requiring low weight (e.g., space, aerospace and automo-
tive) and long life (infrastructure and marine). In some
aerospace applications, thermoplastic polymer composites
are the enabling materials that meet demanding perfor-
mance requirements. However, existing high performance
thermoplastic polymer processing techniques require high
temperatures and high pressures, which lead to high pro-
duction costs.
Engineering polymers, which have good mechanical
properties but relatively moderate processing requirements
due to lower melting and processing temperatures, could be
cheaper alternative matrix materials to the high perfor-
mance polymers currently used in thermoplastic fibre com-
posites for aerospace applications. However, engineering
polymers, especially semi-crystalline polymers such as
polyamides, have relatively low glass transition tempera-
1359-835X/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.compositesa.2006.09.010
*
Corresponding authors. Tel.: +31 152 788 013; fax: +31 152 787 415
(D.P.N. Vlasveld), Tel.: +31 152 786 946; fax: +31 152 787 415 (S.J.
Picken).
E-mail addresses: D.P.N.Vlasveld@tnw.tudelft.nl (D.P.N. Vlasveld),
S.J.Picken@TUDelft.nl (S.J. Picken).
www.elsevier.com/locate/compositesa
Composites: Part A 38 (2007) 730–738