Composites, Green Chemistry, Biodiesel, Carbon Neutrality

1. MATRUSRI ENGINEERING COLLEGE
DEPARTMENT OF SCIENCES AND HUMANITIES
SUBJECT NAME: CHEMISTRY
FACULTY NAME: VISHNU THUMMA
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TOPIC: Composites, Green Chemistry, Biodiesel

2. CHEMISTRY
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COURSE OBJECTIVES:
➢Correlate the properties of materials with their internal structure and use
the for Engineering applications
➢Apply the principles of electrochemistry in storage of electrical energy in
batteries.
➢Gains knowledge in causes of corrosion and its prevention.
➢Attains knowledge about the disadvantages of hard water for domestic and
industrial purposes.
➢Also learns the techniques of softening of hard water and treatment of
water for drinking purpose.
➢Exposed to qualitative and quantitative parameters of chemical fuels.
➢Aware eco-friendly materials and processes.
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3. CHEMISTRY
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COURSE OUTCOMES: After completion of course students will be able to
➢Analyze and apply knowledge of electrodics in calculation of cell
potentials of batteries.
➢Identify the different types of hardness and alkalinities in water and
make use of softening methods, analyze and apply the knowledge of
corrosion for its prevention.
➢Discuss different types of polymers based on their end on use and
the need to replace the conventional polymers with polymers of
engineering applications.
➢Identify and analyze different types of chemical fuels for domestic and
automobile applications.
➢Outline the principles of green chemistry for sustainable environment
and preparation of biodiesel from renewable sources.
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4. UNIT-V Composites, Green Chemistry, Biodiesel
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COURSE OUTCOMES: After completion of course students will be able
to outline the principles of green chemistry for sustainable
environment and preparation of biodiesel from renewable sources.
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5. MODULE-1: Introduction to Composites
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The materials obtained by combining dissimilar materials
together so that they work as single mechanical unit are called
composite materials.
They have properties different from the constituents.

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Constituents of Composites
two essential constituents
• Matrix phase or Matrix
• Dispersed phase
i. Fibres
ii. Particulates
iii.Flakes
iv.Whiskers

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Matrix Phase
(main constituent)
• It is the main constituent of composite.
• It is bonding material which encloses and adheres to reinforcing
material like fibre.
• Transmit and distribute an externally applied load to the dispersed
phase
• Prevents propagation of brittle cracks due to plasticity and softness.
• Ex: Metal Matrix Composite (MMC), Polymer Matrix Composite
(PMC), Ceramic Matrix Composite (CMC).
• PMC: epoxy, polyamide (nylons), phenolics, silicons, polysulphones

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i) Fibre:
• It is a long thin filament of ceramic, metal or polymer having high
length to diameter ratio.
• Its stiffness gives high tensile strength to composite.
• It also causes lowering the overall density of composite.
• The different types are Glass fibres, Carbon fibres, Aramid fibres
(made of liquid crystals).

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ii) Particulates:
• These are small pieces of hard solid material.
• They distribute randomly in a matrix.
• They increase surface hardness and strength.
• They reduce cost, shrinkage and friction.
• Modify thermal and electrical conductivities.
• They bear the applied load and stress transferred from matrix.
• Ex: Concrete, Cermet (ceramic bonded with metals) are
particulate composites.

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iii) Flakes:
These are thin solids having a two-dimensional geometry.
They impart equal strength in a plane compared to fibres.
Packing of flakes can be carried out more efficiently than that of
fibres or spherical particulates.
Mica flakes are used in electrical and thermal insulating appliances.

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iv) Whiskers:
• These are thin strong filaments or fibres made by growing a crystal.
• They are several mm in length and diameter in micros.
• They are made of graphite, silicon carbide, aluminum oxide.
• They give high elastic modules, exceptionally high strength, high
degree of crystalinity.

15. QUIZ
1. The dissimilar materials combined together to work as a single mechanical unit is
called
a) particulates b) polymers
c) composites d) refractories
2. The main constituent of the composite is
a) Whiskers b) dispersed phase
c) matrix phase d) flakes
3. The constituent of dispersed phase which posses high length to diameter ratio and gives
high tensile strength to composites is
a) fibre b) particulate
c) flakes d) whiskers
4. Which of the following constituent bears applied load and stress transferred from matrix
a) fibre b) particulate
c) flakes d) whiskers
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16. MODULE-2: Advantages of Composites
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➢ They have high specific strength.
➢ They do not loose their strength even at high temperatures. The loss
of strength near melting point is very low.
➢ They are hard, tough with good impact and thermal shock resistance.
➢ They have high corrosion and oxidation resistance compared to
metals.
➢ They have low specific gravity and low cost.
➢ Thermal expansion, conductivity and electrical conductivity are low
and can be controlled.
➢ They have better creep and fatigue strength.

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Classification of Composites:
1. Fiber-reinforced composites
2. Particulate composites.
3. Layered composites.

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Fiber-reinforced Composites
➢ It has three components namely filament, a polymer matrix and a
bonding agent which binds filament to polymer.
➢ They have high specific strength, high specific modulus, stiffness and
low density and good mechanical properties.

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Fiber-reinforced Composites
➢ The characteristics of fibre-reinforced composites depend upon nature
and properties of both matrix and fibre, Orientation and distribution of
fibres in matrix, strength of bonds between them and length to diameter
ratio.
➢ For preparing such composites, it is essential that the coefficient
expansion of both fibre and matrix should be very close, both should
not react chemically and fibre should be stable and should retain high
percentage of strength at high temperature.

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a) Glass fibre-reinforced composites:
They contain Glass fibres with polymeric matrix like Nylon, Polyester
to improve characteristics.
They have low density, high tensile strength.
They possess good impact resistance and good chemical and
corrosion resistance.
Uses: They are used in automobile parts, plastic pipes, storage
tanks, floorings and transportation industries.
Limitations: Limited service temperature, because most polymeric
matrices begin to deteriorate or flow at high temperature.

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b) Carbon fibre-reinforced composites:
High performance carbon fibres are used in polymer matrix composites,
which require retention of derived properties even at higher
temperatures and excellent resistance to corrosion along with lighter
weights.
Uses: Military and commercial aircraft structural compounds such as
wing, body, stabilizers, finishing rods, used in military and
commercially used helicopters, for making sports materials like golf
sticks and bats.
Limitations: The use of these materials is limited because of their high
cost.

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c) Aramid fibre-reinforced composites:
• The fiber‐forming substance is a long‐chain synthetic polyamide in
which at least 85% of the amide linkages, (‐CO‐NH‐) are attached
directly to two aromatic rings.
• Kevlar is a very well known and widely used aramid fiber.
• They possess high resistance to abrasion and organic solvents.
• Tough and strong non-conductive materials.
Uses: Used for making automobile brakes and clutches, structural
materials of commercial aircrafts, helicopter parts like rotor blades,
motor housing etc.

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d) Metallic fibre-reinforced composites:
• These consist of a metal or alloy (Al, Ni, Co) matrix and reinforcing
materials like metal oxides (Al2O3) or carbon fibres.
• They possess improved specific strength, stiffness, abrasion
resistance, creep resistance and dimensional stability.
Uses: For making the components of turbine engines.

24. QUIZ
1. Which of the following statement is not correct?
a) composites have high specific strength.
b) composites have better creep and fatigue strength.
c) composites are not corrosion resistant.
d) composites have good oxidation resistant than metals.
2. The components filament, a polymer matrix and bonding agents are present in
a) fibre reinforced composites b) layered composites
c) particulate composites d) all the above
3. The limitation of Glass fibre reinforced composite is
a) corrosion resistant b) limited service temperature
d) low density b) high tensile strength
4. Which of the following composites preferred for making components of turbine engines
a) aramid fiber reinforced composites b) carbon fiber reinforced composites
c) metallic fibre reinforced composites d) glass fibre reinforced composites
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MODULE-3: Particulate-composites
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➢ These are made by dispersing particles of varying size and shape of
one material in a liquid matrix of another material.
➢ In such composites, the matrix as well as particulates shares the load-
bearing function.
➢ Cermets are the important examples in which ceramic bonded with
metal.
➢ Applications: used in many automotive applications including body
panels, bumpers, dashboards, and intake manifolds, brakes etc.

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Layered-Composites
➢ These are formed by piling the layered materials of different properties
on top of each other or a less dense core material sandwiched
between two strong outer sheets.
➢ The properties of these composites depend upon the properties of the
constituents and their geometrical design.
➢ They possess high strength in both directions of reinforcement, but
their shear strength is comparatively low.
➢ Applications: They are extensively used in fabrication of wings of
aircrafts, boat hulls, ship structure parts, building structures etc.

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Applications of composites
• In automobile industries, transportation industries, turbine engines, wire
drawing dies, valves, pump parts, spray nozzles, storage tanks.
• In fabrication of roof and floors, furniture, sport goods, high speed
machinery.
• Marine applications like propellers, shafts, hulls, spares for racing boats
and other ship parts.
• Aeronautical applications like components of rockets, commercial and
military aircrafts and other ship parts.
• Communication antennae, electronic circuit boards like PCB.
• Safety equipment like ballistic protection.

28. QUIZ
1. Which of the following composite is made by dispersing particles in a liquid matrix of
another material
a) fibre reinforced composites b) particulate composites
c) layered compoistes d) all the above
2. The automative parts like body parts, bumpers and dasboards are made using
a) fibre reinforced composites b) particulate composites
c) layered compoistes d) None
3. The composites which are formed by piling the layered materials of different properties
on top of each other are known as
a) fibre reinforced composites b) particulate composites
c) layered composites d) all the above
4. Which of the following composites are extensively used in fabrication of wings of
aircrafts and ship parts?
a) fibre reinforced composites b) particulate composites
c) layered composites d) all the above
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29. MODULE-4: Green Chemistry
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Green chemistry is the design of chemical products and processes that
reduce or eliminate the use and generation of hazardous substances.

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Twelve Principles of Green Chemistry
1. Prevention of waste.
2. Atom economy.
3. Less hazardous chemical synthesis.
4. Designing safer chemicals.
5. Safer solvents and auxiliaries.
6. Design for energy efficiency.
7. Use of renewable feed stocks.
8. Reduce derivatives.
9. Catalysis.
10. Design for degradation.
11. Real-Time analysis for pollution prevention.
12. Inherently Safer Chemistry for Accident Prevention.

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Prevention of Waste/ By products:
It is better to prevent waste than to treat or clean up waste after it is
formed.
In a manufacturing process, in addition to by products the unreacted
starting materials also form a part of waste.
If the waste is disposed in the atmosphere, sea or land it adds to the
pollution.

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Atom Economy:
The maximum incorporation of the atoms of the reactants and
reagents into the final products is called atom economy.

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Less hazardous chemical synthesis:
It is important to prevent or minimize the formation of hazardous products
which may be toxic or environmentally harmful.
Therefore, for the same conversion an alternative process may be used.

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Designing safer chemicals: The chemicals or pharmaceuticals
synthesized should be safe to use.
For example: A drug “thalidomide” prescribed for nausea and vomiting
during pregnancy had adverse effects, led to birth defects like deformed
limbs. Therefore, chemical products should be designed to affect their
desired function while reducing toxicity.

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Safer solvents and auxiliaries: The solvents used in a reaction should
not cause environment pollution.
For example: Benzene and CCl4 are highly carcinogenic. Alternative
solvents like water, ethanol are green solvents.
Design for energy efficiency: Conventional heating methods are not
energy efficient and the rate of reaction may be slow. The alternative
energy sources like microwave, ultrasound or sunlight/UV may be used.

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Use of renewable feed stocks: Raw material feed stock should be
renewable.
Reduce derivatives: Unnecessary derivatization like blocking groups,
protection or de-protection, temporary modification of physical or chemical
methods should be minimized.
Catalysis: Catalytic reagents are superior to stoichiometric reagents. Phase
transfer catalysts in organic synthesis and biocatalysts (yeast, enzymes
etc.) may be used.

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Design of degradation: Chemical products should be designed so that
at the end of their function they do not persist in the environment and
breakdown into small products.
Real-time analysis: Analytical methodologies need to be developed to
control the formation of hazardous substance.
Accident Prevention: The substance and the form of chemical used in a
process should be chosen so as to minimize chemical accidents,
explosion and fires.

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Examples of Clean Technology
Ultra sound assisted Cannizaro reaction:
Williamson synthesis (microwave/ultrasound simulated):

39. QUIZ
1. Green chemistry deals with
a) production of green plants
b) reduction of green plants
c) production of hazardous chemicals
d) reduction of hazardous chemicals
2. The maximum incorporation of the atoms of the reactants and reagents into the final
products is called ______
a) prevention of waste b) atom economy
c) yield d) productivity
3. Which of the following is a green solvent
a) water b) benzen
c) carbon tetrachloride d) pyridine
4. Which of the following is not a green catalyst
a) phase transfer catalyst b) enzyme
c) biocatalyst d) none 39
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MODULE -5 Biodiesel
➢ It is a natural and renewable domestic fuel alternative for diesel
engines made from vegetables oils, mostly soya and corn.
➢ It contains no petroleum, is non-toxic and biodegradable.
➢ Vegetable oils contain 90-98% triglycerides along with small
quantities of mono and triglycerides, free fatty acids, phospo lipids,
phosphotides, carotenes etc.
➢ Triglycerides are esters of long chain fatty acids such as stearic acid,
palmitic acid, linoleic acid, oleic acid.

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➢Biodiesel is produced from the seeds of Jetropa.
➢Vegetable oils are not used directly as diesel fuel due to their high
viscosities.
➢Therefore trans-esterification of vegetable oils is done to reduce the
viscosity.

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Trans-esterification is the process of exchanging the alkyl group of an
ester with the alkyl group of an alcohol. These reactions can be catalyzed
acids, bases or enzymes.

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Properties:
➢ The color of biodiesel ranges from golden to dark brown,
depending on the production method.
➢ It is slightly miscible with water, has a high boiling point and
low vapor pressure.
➢ The calorific value of biodiesel is about 37.27 MJ/kg. This is 9%
lower than regular petrodiesel.
➢ The flash point of biodiesel exceeds 130 °C, significantly higher
than that of petroleum diesel which may be as low as 52 °C.
➢ Biodiesel has a density of ~0.88 g/cm³, higher than petrodiesel
(~0.85 g/cm³).

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Significance:
➢ It can be produced from renewable domestic resources.
➢ Energy efficient.
➢ Burns clean, which results in significant reduction of all types of
pollutants that contribute to smog and global warming and omits up
to 85% fewer cancer causing agents.

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Limitations:
➢ Generally has higher cloud and pour point, so it will freeze at
higher temperature than conventional diesel.
➢ It is not compatible with some metals and plastics.

46. QUIZ
1. The sources of biodiesel are
a) seeds of Jetropa b) vegetable oils
c) corn d) all the above
2. The chemical reaction by which biodiesel is produced
a) transesterification b) esterification
c) emulsification d) saponification
3. Which of the following is not correct statement
a) biodiesel is slightly miscible in water.
b) the carlorific value of biodiesel is greater than petrodiesel.
c) the flash point of biodiesel is greater than petrodiesel.
d) the density of biodiesel is higher than the petrodiesel.
4. Which of the following is limitation of biodiesel?
a) it freeze at low temperatures.
b) not compatible with some metals and plastics.
c) high cloud and pour points.
d) all the above
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MODULE -6 Carbon Neutrality
It refers to achieving net zero carbon emissions by balancing a
measured amount of carbon released with an equivalent amount
sequestered or offset, or buying enough carbon credits to make up
the difference.

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It is used in the context of carbon dioxide releasing processes
associated with transportation, energy production, and industrial
processes such as production of carbon neutral fuel.

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Carbon-neutral status can be achieved in two ways:
1. Balancing carbon dioxide released
into the atmosphere from burning
fossil fuels, with renewable energy
that creates a similar amount of useful
energy, so that the carbon emissions
are compensated, or alternatively
using only renewable energies that
don't produce any carbon dioxide
(also called a post-carbon economy).

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2.Carbon offsetting by paying others to
remove or sequester 100% of the carbon
dioxide emitted from the atmosphere.
For example by planting trees – or by funding
'carbon projects' that should lead to the
prevention of future greenhouse gas
emissions, or by buying carbon credits to
remove (or 'retire') them through carbon
trading.

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Becoming carbon neutral involves three basic steps:
CALCULATE carbon emissions and other greenhouse gases from
activities.
REDUCE emissions wherever possible through increased efficiencies.
BALANCE the remainder by purchasing carbon offsets.
In the long term, voluntary carbon offsets are expected to be a transient
mechanism as low carbon strategies become business as usual in the
future.

52. QUIZ
1. Carbon neutrality is
a) achieving zero carbon emission
b) balancing carbon using sequesters
c) buying carbon credits to makeup the difference
d) all the above
2. The steps involved in becoming carbon neutral are
a) calculate b) reduce
c) balance d) all the above
3. Carbon neutrality can be achieved by using
a) wind energy b) solar energy
c) biomass c) all the above
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