Chemical Engineering March 2016 - 18

Newsfront
FiGure 1. As wind power becomes more
universal, the manufacturing processes for
turbine components must also grow
more efficient
Cutting-edge Composites:
Materials for a New Era
The combination of advanced materials and processing techniques results in new composites
that can aid industries in achieving increased levels of efficiency
In BrIef
ElEvATiNg WiNd
TuRBiNE EFFiCiENCy
pRoTECTiNg AgAiNST
THE ElEMENTS
FlyiNg HigH WiTH
CERAMiCS
BooSTiNg MATERiAlS
viA 3-d pRiNTiNg
CoMpoSiTE
MAiNTENANCE
B
Reinforcement
Release paper
Matrix
Oven
Release paper
d
18
Prepreg
ue to their considerable diversity, there are several widely used preparation
methods for industrial composites. Hexcel's Wind Energy team explains
one such method, wherein industrial composites are produced on
horizontal (diagram) or vertical impregnation lines. A thermosetting, hot-melting
epoxy resin is blended and filled into a resin bath, which is used for casting a
film on silicone-coated release paper. The weight of the resin film is adjusted by
the gap between the resin bath and the release paper, allowing for precise control
of resin distribution and weight, and thus precise control of final composite
weight. The reinforcement material (glass, carbon or aramide) is added onto the
epoxy resin film, and the assembly is subsequently pulled through a heated impregnation
zone, where the reinforcement material is impregnated by the resin,
ensuring that no dry fiber is left. At this point, the release paper is removed, and
the impregnated fabric (also called prepreg) is wound onto a core with a thermoplastic
polyfilm interleaf.
❏
y their nature, composite materials
lend themselves to a vast array of
applications. A composite's constituent
materials and processing
methods can be tailored to yield seemingly
infinite combinations of physical and chemical
properties. Although composites have long
been essential in countless industries, technological
advances continue to expand their
reach, and industries are increasingly seeking
out cutting-edge materials to increase operations'
sustainability. This article focuses on
innovative composite materials and processing
techniques designed for use in two major
How is an industrial composite made?
Horizontal
Hexcel
industries where sustainability and efficiency
are key - wind power and aerospace.
Elevating wind turbine efficiency
A major application area for composite materials
is in wind turbines (Figure 1). With the
push for more renewable sources of energy,
wind-farm construction has intensified in recent
years. Wind turbines must be able to
withstand continued operations in extreme
heat, freezing temperatures, precipitation,
lightning, and of course, high winds. Composites'
versatility and strength make them
well suited for these environmental demands.
Furthermore, the composite materials used
for turbine components can actually make
the overall turbine-manufacturing process
more efficient.
Although many parts of a wind turbine,
including the nacelle (the enclosed box that
houses the various generating components)
and spinner, can be constructed of composite
materials, composites are mainly used for
the rotor blades. " They have to be light, stiff,
long-lasting and need to resist environmental
influences, " says Johannes Moser, R&T manager
at Hexcel Corp. (Stamford, Conn.; www.
hexcel.com). Hexcel's portfolio consists of epoxy-resin
composites reinforced with glass or
carbon fiber for high fatigue resistance. Since
rotor blades can be massive structures, they
must be produced in a very efficient manner,
and the composite material's properties and
handling requirements must withstand the
rigors of the rotor-manufacturing process.
" To develop an epoxy resin for wind-energy
applications, the reaction enthalpy should fit
the process. Furthermore, the mechanical
properties of the resin have to fit with glass
and carbon fiber, " explains Hexcel's Wind
ChemiCal engineering www.Chemengonline.Com marCh 2016
http://www.hexcel.com http://www.Chemengonline.Com
Chemical Engineering March 2016

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