JEC COMPOSITES MAGAZINE - Issue #101 - November/December 2015 - 52

green composites

Bamboo-based sandwich
panels for aeronautics
A new bamboo composite panel is currently being developed by
VESO Concept for aeronautics applications. The first results are
very promising and show all the potential of this particular fibre
for new green composites in highly technical environments.

By
david hardY, cEo,
alinE rogEon
Phd maTErials rEsEarch EnginEEr,
maThiEu BouTin
EnginEEring sTudEnT
vEso concEPT

O

ver the past decade, there has been
a growing interest in natural fibres:
scientific communities first, followed
by industrial companies who saw all their
potential to replace glass fibre in current
composites. Natural fibres are renewable,
have a low cost, a low density and interesting mechanical properties. Nowadays,
automotive and aeronautics interiors are
mainly made of glass fibre, carbon, aramid
or aluminium. Although these materials
exhibit good mechanical properties, they
require a high amount of energy for their
manufacturing. Moreover, regulations on
materials recycling and the reduction of
NOx and CO2 emissions are urging industrial companies to find alternatives. Natural
fibres are one of them.

Bamboo fibres
as a reinforcement
In Europe, flax fibres are the main natural
fibre used as a reinforcement in biocomposites. Indeed, as this fibre has been used in
textiles for thousands of years, textile industry manufacturers used their know-how to

develop technical flax fabrics for composite
applications. Only a few teams are working on the development of bamboo-based
composites. But bamboo is an interesting
natural fibre. This plant grows quickly all
around the world, without pesticides or
irrigation. Moreover, bamboo absorbs 4
times more CO2 and releases 35% more
oxygen than a tree forest for a same surface.
It also has interesting mechanical properties
with an ultimate tensile strength ranging
between 750 and 950 MPa. Therefore, its
use in biocomposites is relevant.
This is the reason why VESO Concept
decided to develop a new biosourced
composite reinforced with bamboo fibres
for aeronautics. Due to their hydrophilic
nature, natural fibres are not compatible
with most existing polymeric matrices and
resins. This lack of compatibility makes impregnating fibres with resin more difficult.
This can result in the apparition of some porosity and a drop in mechanical properties.
Several physical and chemical treatments
were tested and used on bamboo fibre to
improve the adhesion between matrix and
fibre. With optimum treatments, the wettability of fibres was enhanced by 53%.

52 jec composites magazine / No101 November - December 2015

To produce a composite material with
the best mechanical properties, the epoxy
resins selected should have good mechanical properties. Figure 2 shows a dynamic
mechanical analysis (DMA) of an epoxy
resin. Moreover, because of these resins'
glass transition temperature (Tg), it is possible to work at low temperatures (below
150°C). Furthermore, epoxy resins have a

Fig. 1: Bamboo wood and reinforcement
Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #101 - November/December 2015
