Sustainable composites
John Summerscales
Sustainability
Brundtland Commission Report (1987)
The World Commission on Environment and
Development suggested the following
definition of Sustainable Development:
"Meeting the needs of the present
without compromising the ability of
future generations to meet their own
needs."
Sustainability
• Bruntland emphasised the need to balance:
economics
o environment
o social
o governance
o
• Now generally reduced to “Triple E”
Economy
o Ecology
o Equity
o
Sustainable composites
This lecture
describes materials from natural sources,
without prejudice to the results of any future
Quantitative Life Cycle Analysis (QLCA)
which may (or may not)
make the case for these materials
being more environmentally-friendly
than equivalent systems manufactured from
man-made fibres and synthetic resins.
Typical fibre properties
• The data on the next three slides is from:
o
NL Hancox, Fibre Composite Hybrid Materials,
Elsevier Applied Science, Barking, 1981.
o
TJ Reinhart, Engineered Materials Handbook 1:
Composites, ASM International, 1987.
o
Chand et al, Journal of Materials Science,
1988, 23(2), 381-387.
• where a range is given in the references,
the arithmetic mean is shown in the graph
Density of fibres
Bast (plant stem)
Leaf Seed Animal
Synthetic
1500
kg/m3
Carbon
Aramid
Glass
Silk
Coir
Cotton
Sisal
Pineapple
Jute
Hemp
Flax
Young’s moduli of fibres
Bast (plant stem)
Leaf
Seed
100 GPa
Animal
Synthetic
Carbon
Aramid
Glass
Silk
Coir
Cotton
Sisal
Pineapple
Jute
Hemp
Flax
Strengths of fibres
3 GPa
Bast (plant stem)
Leaf
Seed
2 GPa
Animal
Synthetic
1 GPa
Carbon
Aramid
Glass
Silk
Coir .
Cotton
Sisal
Pineapple
Jute
Hemp
Flax
Fibre specific moduli and strengths
• Specific value is (modulus or strength)/density
o
i.e. (MN/m2)/(kg/m3) = MN.m/kg
Modulus
Strength
Flax
65.8
0.55
Hemp
46.1
0.61
Jute
39.5
0.57
Glass
27.8
1.33
Aramid
86.1
1.92
Carbon
109.9
1.40
Aluminium
25.5
Flax/Linseed (Linum usitatissimum L.)
• Mike Felstead: Flax and linseed fibres as
reinforcement for epoxy composites,
BEng Composites, June 1995.
E-modulus
(GPa)
UTS
(MPa)
Elongation
(%)
Q: Queens flax
134±55
141±66
1.14±0.4
S: Silsoe flax
117±78
93±53
1.23±0.51
H: Seale-Hayne linseed
79±53
71±50
1.36±0.49
Materials
Flax
Flax and linseed
are cultivars grown
for fibre or seed
respectively
Flax Field, Providence by Hazel Barker
From http://www.art.com/asp/sp-asp/_/pd--10125356/Flax_Field_Providence.htm
Flax: growth stages
• 12 distinct growth stages in the flax plant:
o
Growth stages 1 & 2

o
Growth stages 3 & 4

o
buds visible to full flower
Growth stages 9, 10 & 11

o
stem extension
Growth stages 6, 7, & 8

o
1st pair of true leaves unfolded to third pair of true leaves unfolded
Growth stage 5

o
cotyledon (seed leaf) to growing point emerged
late flower to brown capsule
Growth stage 12

seed ripe
FLAX: growth stages
Life cycle of the flax plant consists of
• a 45-60 day vegetative period,
• a 15-25 day flowering period, and
• a maturation period of 30 to 40 days
J A Turner “Linseed Law” BASF (UK) Limited, 1987 via http://www.flaxcouncil.ca/images
Flax: from plant to fabric
• harvest (combining or pulling)
• retting (dew-, wet-, stand- or enzyme-retting)
o
enzymes (e.g. pectinase digests pectin binder)
• decortication (scutching)
o
o
o
•
•
•
•
Hammer mill
Fluted rollers
Willower
cleaning (removal of shive)
carding (brushing/combing aligns fibres) > sliver
spinning (twisting binds fibres) > yarn/filament
weaving, braiding, knitting, etc
Hemp (Cannabis sativa L.)
• annual plant native to central Asia and
grown in China over 4500 years ago.
• probably reached central Europe in the Iron
Age (circa 400 BC)
• evidence of growth in the UK
by the Anglo-Saxons (800-1000 AD).
• does not require fertiliser, herbicides or
pesticides to grow well
• in suitable warm conditions,
it can grow to 4 metres in just 12 weeks.
Hemp (Cannabis sativa L.)
Disadvantage?
• some strains of this plant are ...
psychotropic
• those good for the above are not best for fibre
• ... but good fibre plant can be used to
disguise plants grown for drugs
• new strains of fibre plant with distinctive
leaf colours are under development
Henry Ford car 1941
hemp and flax
fibres used in
resin matrix
composites
for body of
Henry Ford
car able to
withstand
ten-times the
impact on an
equivalent
metal panel
Video
made from plant based materials
"the axe bounced, and there was no dent"
Image from http://www.chanvre-info.ch/info/en/About-Henry-Ford-s-Car.html
Henry Ford tries out his first car
Jute
Corchorus capsularis. L. - white jute
C. olitorius L. - Tossa jute.
• The Golden Fibre
http://www.bdcom-online.com/shathi/jute.htm
• Biotechnology in jute fibre processing
http://www.epbbd.com/month23/Background.htm
Kenaf (Hibiscus cannabinus L.)
• fibre plant native to east-central Africa.
• common wild plant of tropical and
subtropical Africa and Asia
• grown for several thousand years for food
and fibre
• unique combination of
long bast and short core fibres
• two crops/year in Malaysia
Nettle (Urtica dioica)
• Nettles yield ~ 8-10 tonnes fibre/acre
http://jacksonsrow.topcities.com/tikun_olam/nettle.html
• far stronger than cotton but is finer than
other bast fibres such as hemp
• much more environmentally friendly fibre
crop than cotton, which requires more
irrigation and agrochemical input
Nettle
• 24 v/o nettle/epoxy
E/σ’ = 9 GPa/91 MPa
• 23 v/o nettle/phenolic E/σ’ = 5 GPa/13MPa
• 21 v/o flax/epoxy
“strength and stiffness
are more than twice as high”
Ann-Jeanette Merilä, Stinging nettle fibres as reinforcement in thermoset matrices,
MSc Engineering/Materials Technology, Luleå University of Technology
http://epubl.luth.se/1402-1617/2000/235/index-en.html
Rules-of-mixture for NFRP
• Young’s modulus:
o
Ec = κηdηlηoVfEf + VmEm
• Strength:
o
σ’ = κVfσf’ + Vmσm*
• κ = fibre area correction factor
• ηd = fibre diameter distribution factor
κ = fibre area correction factor
ηd = fibre diameter distribution factor
• κ corrects for true area or irregular CSA
when apparent fibre diameter is measured
• ηd = fibre diameter distribution factor
o
data below from Christophe Baley at USB
Are natural fibres good?
Environmental issues
• Depletion of soil nutrients/fertiliser
• Competition from weeds/herbicides
• Competition from animals/pesticides
Economic issues
• Agricultural subsidies
• Dependence on weather
• Market price vs other producers
Are natural fibres good?
• “natural fibre production requires less than
10 percent of the energy used for production
of PP fibres (around 90 GJ/tonne)”, but .....
JEG van Dam and HL Bos,
Consultation on natural fibres:
the environmental impact of hard fibres and jute in non-textile industrial applications
ESC-Fibres Consultation no 04/4, Rome, 15-16 December 2004.
Are natural fibres good?
..... that data is total energy input
for jute fibre cultivation (excluding
field labour, retting and decortication)
when grown by numerous small farmers
utilising labour and animal power
with limited agrochemicals and machinery
Are natural fibres good?
Data from TexFlax project thesis for flax:
• ploughed
• seed sown
• pesticide applied (twice)
• N applied
• P/K applied
• herbicide applied (twice)
• harvested
How much fuel went through the tractor, and
how much energy was in the sprayed materials?
Life Cycle Assessment
• Four different phases [Brady]:
Goal and scope definition:
in the context of the intended application.
o Inventory analysis:
collect data, quantifies relevant inputs and outputs.
o Impact assessment:
translates inventory analysis into impacts
evaluating significance of the respective impacts.
o Interpretation:
conclusions and recommendations for decision
makers
Quantitative life cycle assessment (QLCA)
o
Adisa Azapagic
•
Environmental impact classification factors:
1.
2.
3.
4.
5.
6.
7.
8.
Non-Renewable/Abiotic Resource Depletion (NRADP)
Global Warming Potential (GWP)
Ozone Depletion Potential (ODP)
Acidification Potential (AP)
Eutrophication Potential (EP)
Photochemical Oxidants Creation Potential (POCP)
Human Toxicity Potential (HTP)
Aquatic Toxicity Potential (ATP)
Nilmini’s interim analysis
Ploughing
Sowing
Water
Herbicides
Pesticides
Fertiliser
Dessication
Harvest
Rippling
Retting
Decortication
Hackling
Carding
Spinning
Environmental Impact Classification Factor
Land clearance
Environmental Impact for Flax fibre:
Acidification Potential (AP)
Aquatic Toxicity Potential (ATP)
Eutrophication Potential (EP)
Global Warming Potential (GWP)
Human Toxicity Potential (HTP)
Non-Renewable/Abiotic Resource Depletion (NRADP)
Ozone Depletion Potential (ODP)
Photochemical Oxidants Creation Potential (POCP)
Noise and Vibration
Odour
Loss of biodiversity
Very High Effect
Low Effect
No Effect
See also http://www.netcomposites.com/downloads/03Thurs_Summerscales.pdf - slide 15
Environmental burdens: flax
• embodied energies for flax (no-till agriculture):
o
o
•
•
•
•
•
54 GJ/tonne for sliver (55 GJ/tonne for glass mat)
80 GJ/tonne for yarn (32 GJ/tonne for continuous glass)
minimum < middle < maximum
no till < conservation agriculture
< mouldboard plough
organic fertiliser < agro-chemicals
biological control of pests
< pesticides
water- < dew- < bio-retting
sliver < spun yarn
QLCA: Le Duigou vs Dissanayake
Key differences:
•Higher level of nuclear power in the French energy mix
•UK plants desiccated at mid-point flowering
but French plants allowed to set seed
•UK yield only 6000 kg/ha
but French yield 7500 kg/ha at harvest
•UK study excluded
photosynthesis and CO2 sequestration
•UK study allocated all burdens to fiber
French study allocated on mass of product
as a proportion of all (co-)products
The future ?
• Extracting fibre without damage
• Effective coupling agents
o
cellulose chemistry instead of silanes
• Environmental durability
barriers to prevent moisture absorption
o sterilise fibres to prevent biodeterioration
o
• Quantitative Life Cycle Assessment (QLCA)
• Other issues ?
• BS8905 adds “Land Use” as 9th EICF
• growing food vs fuel, feedstock, fibre
Bio-based resin systems
Thermoplastics
• CPLA (polylactide aliphatic copolymer)
• PCL (polycaprolactone)
• PGA (polyglycolicacid)
• PHA (polyhydroxyalkanoate)
PHB (poly-beta-hydroxybutyrate)
o PHBV (polyhydroxybutyrate-valerate)
o
• PLA (polylactide)
• DuPontTM Sorona®
Bio-based resin systems
Thermosets
• Acrylised epoxidised soybean oil
(Aropol Envirez 5000, UCB Ebecryl)
• Cashew Nut Shell Liquid (CNSL)
• Epoxidised linseed oil
.. and .. polycarboxylic acid anhydrides
• Partially norbornylized linseed oil
(Dilulin®)
• Rapeseed-oil derived resins
Summary
• sustainability
• natural fibres
bast (stem), leaf, seed, animal
o temperate or tropical zone
o growth, harvest, retting, separation, etc
o
• life cycle assessment (ISO 14040 series)
• environmental impacts (8 EICF + land use)
• bio-based resins