1. No category

The use of Recycled Carbon Fibre commingled with Polymer Fibres in
Non-Woven Mats
 epzkhw@exmail.nottingham.ac.uk Supervisor: Dr T A Turner
Dr Kok Wong
Background & Motivation
Methodology – Manufacturing & Testing
Processes for the recycling of carbon fibres are
being developed but few low cost reuse routes
exist. One option for the manufacture of an
intermediate material which could be used in
current composites manufacturing processes is
the papermaking process for the production of
non-woven
mats
commingled
with
thermoplastic fibre.
Multiple layers of dry mat were stacked and
trimmed ready for moulding. Agglomerated
bundles of recycled carbon fibre were visible in
the produced mats.
Fig 7. Sample
of composite
plaque
Materials
Technical Fibre Products Ltd
supplied various forms of
recycled carbon fibre mat for
this project:
• 100gsm Random Virgin Fibres
• 100gsm Random Recycled Fibres
• 20gsm Aligned Virgin Fibres
• 20gsm Aligned Recycled fibres
Results – Mechanical Properties
Fig 3. Images of
mats showing
bundles and
curved nature of the polymer fibres
Fig 4. Moulding tools for plaque fabrication
Fig 1. 600
mm wide
rolls of
material
The project encountered difficulty in producing
truly random or aligned mats. The long and
curly nylon fibre reduced the quality of fibre
alignment. Reinforcing properties of the
recycled carbon fibre appeared lower
compared to the virgin counterpart and this
was attributed to the shorter fibre length and
poorer dispersion of the filaments. No
significant difference in bonding was found
between virgin and recycled fibres.
Fig 8. SEM
image of
recycled
carbon fibre
reinforced
composite
12
120
Output: Recycled fibre
Input: Shredded prepreg
Fig 5. Moulding profile for plaque fabrication
Composite plaques were tested to determine
their tensile and flexural properties. Void
content within the plaques were measured.
Interfacial adhesion between fibre and nylon
matrix was analysed via SEM images.
Tensile modulus, GPa
12mm long virgin carbon fibre, Tenax®-A HT
C124, was supplied by Toho Tenax. Toray T600
carbon fibre was recovered from MTM28-2
prepreg scrap supplied by Cytec via a fluidised
bed process at the University of Nottingham.
The fibres were commingled with Grilon
BA3100 PA6/PA66 fibre from EMS-Griltech.
10
4
0
Recycled random
100gsm
Virgin random
100gsm
Recycled aligned
20gsm
Virgin aligned
20gsm
Recycled aligned
20gsm
Virgin aligned
20gsm
120
Results – Process Optimisation
80
60
40
20
0
0
2
4
6
8
10
12
14
16
18
Fibre length, mm
20
22
Due to the 2-phase nature of the polymer
employed in these trials significant issues were
encountered with
optimisation of the
moulding temperature and pressure. Poor
consolidation was achieved in many cases.
Methodology – Experimental Design
Using the supplied
Recycled CF
Production of
nonwoven mat
materials, several
PA fibre
layers of mat were
Mat
laid-up and composite test
characterisation
plaques were manufactured
Composite
by hot pressing. Several
plaque
fabrication
moulding conditions were
Composite
used in an effort to optimise the
plaque
characterisation
laminate quality by minimising
porosity. Samples were tested
via tensile and flexural testing standards.
100
Tensile strength, MPa
Cummulative frequency, %
6
2
100
Fig 2. Fibre
length
distributions
8
80
60
40
20
0
Recycled random
100gsm
X10
X10
Recycled random 100gsm mat
Virgin random 100gsm mat
Fig 6. Optical photomicrographs of high
porosity levels
Virgin random
100gsm
Next Steps
The project demonstrates a promising route to
exploitation of recovered carbon fibres. The
results of the project have been used as the
basis for a further collaborative proposal
through the Technology Strategy Board. The
work also includes input from BMW/SGL and
Jaguar Land Rover.