Chapter 5 Mechanical Engineering Materials 22343

Program: Diploma(Mechanical)
Class: SYME
Course: Mechanical Engineering Materials(22343)
Unit 05: Non-metallic and Advanced Materials
Lecture 12: Polymeric Materials - types, characteristics

1. Name of the Trainer :- Prof. S. B. Deshmukh
2. Years of Experience :- 8 Years
3. Domain Expertise :- Mechanical Engineering
www.sandipuniversity.edu.in
Presented By 02
https://www.sandipfoundation.org/
Department Of Mechanical Engineering,Sandip Polytechnic,Nashik

Unit 5 Non-metallic and Advanced Materials 03
Topic to be covered
5.1 Polymeric Materials i. Polymers- types, characteristics, ii. Properties and uses of
Thermoplastics, Thermosetting Plastics and Rubbers.
5.2 Thermoplastic and Thermosetting Plastic materials
5.3 Characteristics and uses of ABS, Acrylics. Nylons and Vinyls,Epoxides, Melamines
and Bakelites
5.4 Rubbers: Neoprene, Butadiene, Buna and Silicons – Properties and applications.
5.5 Ceramics –types of ceramics, properties and applications of glasses and
refractories
5.6 Composite Materials - properties and applications of Laminated and Fibre
reinforced materials
5.7 Advanced Engineering Materials Properties and applications of Nano
materials and smart materials

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Polymer Materials
Introduction to polymer :
Polymers are organic materials having carbon as the common element in their
makeup.
They have large molecules known as macro molecules , which are formed by repeated
linking (polymerization) of individual molecules called monomers (single unit) and
thousands of such monomer joined together to form a large molecules of colloidal
dimension, called macro molecule.
The naturally occurring polymers include protein, cellulose, resins, starch, shellac and
lignin.
They are commonly found in leather, fur, wool, cotton, silk, rubber, rope wood and
many others.
There are also synthetic polymers such as polyethylene, polystyrene, nylon, terylene
etc.

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Polymer Materials
Characteristics of polymers :
Good corrosion resistance
Low density
Low co-efficient of friction
Good moldability
Excellent surface finish
Poor mechanical properties & temperature resistance
Application of polymer :
It is used for fibre optics
Contact lenses
Ropes
Brush bristles
Films
Refrigerators door gaskets etc

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Polymer Materials
Classifications of polymer :
1. According to origin
a. Natural polymer
b. Synthetic or artificial polymer
2. According to thermal behavior
a. Thermoplastic polymer
b. Thermosetting plastic polymer
3. According to structure
a. Link polymer
b. Branched polymer
c. Crossed link polymer
4. According to form
a. Plastic b. Elastomers c. Fiber and resins

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Plastics
Plastic is an organic polymer which is easily shaped by the application of heat and
pressure.
They are less brittle than glass but can be made equally transparent
and smooth.
They resist corrosion and action of chemical.
Properties of plastic :
Light in weight
Good corrosion resistance
Good resistance to acid, base and moisture
Low thermal and electrical conductivity
Wide range of colours
Low modulus of rigidity

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Plastics
Type of plastics : Types of plastic material are classified in to three types
1. Thermoplastics plastics
2. Thermosetting plastics
3. Elastomers (Rubber)
1. Thermoplastics :
Thermoplastics are the liner polymers without any crossed linking in their structure.
They become soft when heated and under this condition, they can easily deform to
their desired shapes.
They become hard on cooling.
This type of plastic can be heated and cooled any number of times, only they
should not be heated above their decomposition temperature.
Thermoplastics are weaker, softer and less brittle as compare to thermosetting
plastics.

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Plastics
Examples of thermoplastics are :
a. Polyethylene
b. Polypropylene (PP)
c. Polyvinylchloride(PVC)
d. Polystyrene
e. Polytetrafluoroethylene (PTFE)
f. Nylon
g. Acrylic
h. Polycarbonate
Uses : Toys, lenses, anticorrosion seals, cams, bearings, floor coverings, magnetic tapes
etc

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Plastics
2. Thermosetting plastics :
Thermosetting materials having three dimensional network of primary bond with
covalent cross-links predominating betweens chains.
They become soft during their first heating and become very hard during cooling.
They do not soften during subsequent heating and rather become harder due to
completion of cross-linking.
They do not have a resale of scrap value.
Examples of thermosetting materials are :
a. Phenol formaldehyde (PF) e. Epoxies
b. Urea formaldehyde(UF) f. Silicones
c. Melamine formaldehyde(MF) g. Rubber
d. Polyesters

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Plastics
Uses of thermosetting materials are :
Electric switches, TV cabinets, camera bodies, automobiles parts, helmets etc.

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Plastics
3. Elastomers (Rubber) :
Elastomers are polymers which exhibits the unique properties of high elasticity,
stretching five to ten times to their original length on loading in tension and reverting
back to their original dimension on release of the load.
The best known elastomer is natural rubber and the raw material is latex.

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Plastics

14
Types of Various Thermoplastic Materials
1.Acrylonitrile Butadine Styrene Plastics (ABS)
ABS materials are those containing acrylonitryle, butadiene and styrene monomers in
varying proportion, both as terpolymers and blend
Characteristics / Properties of ABS :
ABS materials are tough, hard and rigid.
It has good chemical and heat resistance.
Ease of processing and machining.
It has low water absorption and resistance to creep.
They are unaffected by water, inorganic salt, alkalis, and many acids.
They are soluble in ketones,aldehydes, esters etc.
Application of ABS :
It can be thermo-formed, pressure formed, blow molded, sheared, sawed, drilled, or
even "cold stamped".
Joints can be ultrasonic welded, thermo-welded, and chemically bonded.

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Application of ABS :
Commonly used for
telephone bodies, safety
helmets, piping, furniture,
car components, TV
casings, radios, control
panels, and similar.
Valve bodies, material
handling equipment.

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2.Acrylic (Polymethyl Methacrylate (PMMA))
The most widely used acrylic plastic is polymethyl methacrylate.
They are hard, rigid material, they are primarily notable for excellent optical
properties.
Characteristics / Properties of Acrylic :
PMMA has high degree of optical clarity.
Transmitting 92 % of incident light.
It is highly resistant to weathering.
It is attacked by concentrated acid, but not by alkalis.
PMMA has low mechanical properties.
Application of Acrylic (PMMA):
Lenses, drafting equipment, roof lighting and dome,
sink, bath, air craft light fixture, sanitary ware,
hospital equipment.

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3.Nylons(polyamides)
It is also known as nylatron, nylafil and plaskon.
It was orignally introduced in market in the form of fibres and fabrics.
It is produced by series of condensation reaction between amine and organic
acids.
Characteristics / Properties of Nylons :
High elongation.
Excellent abrasion resistance
Good mechanical toughness
Melts instead of burning
Good specific strength
High resistance to many chemicals
Good electrical insulation properties

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Application of Nylon :
Solid nylon is used for mechanical parts such as machine screws, gears and other low
tomedium stress components previously cast in metal.
It is also used in gears, bearings, cams, carpets, pouches, rope and tyres etc.

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4.Vinyl
Another large volume plastic material, vinyls comprise
a large number of diverse types.
The most common type is PVC (polyvinyl chloride)
Characteristics / Properties of vinyl :
Good mechanical strength,
Excellent chemical and water abrasion resistance,
Rigid and flexible in nature
Application of vinyl :
1. Used in bottles,
2. Pipe,
3. Floor covering,
4. Raincoat,
5. Electrical wire insulation etc.

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5.Polypropylene (PP)
Polypropylene, also known as polypropene, is a thermoplastic polymer used in a wide
variety of applications including packaging, textiles, stationery etc.
An addition polymer made from the monomer propylene, it is rugged and unusually
resistant to many chemical solvents, bases and acids.
Characteristics / Properties of Polypropylene :
Polypropylene is a light weight material.
Its tensile strength is high.
It shows strong resistance towards stress and cracking.
It acts as an excellent insulating substance.
Polypropylene does not get affected by moisture as its moisture absorption is very low.
Melting point of polypropylene is 160 °C. Therefore, unlike other polymers (polyethylene,
polypropylene), it is capable of being operational even at a very high temperature.

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Characteristics / Properties of Polypropylene :
Polypropylene remains unaffected by chemicals like alkaline substances, acids,
degreasing agents, electrolytic attacks, etc.
Polypropylene is crystalline in nature and possess a regular geometrical shape
Applications of Polypropylene :
1. Hair dryer
2. Refrigerator parts
3. Automotive parts
4. Radio and TV cabinets
5. Vacuum cleaner body
6. Pipes, tanks spray nozzle etc.

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6.Poly Tetra Fluoro Ethylene(PTFE) or Teflon :
In chemistry, polytetrafluoroethylene (PTFE) is a synthetic
fluoropolymer or tetrafluoroethylene that finds numerous
applications.
PTFE is most well known by the DuPont brand name Teflon.
It is manufactured by addition polymerization technique.
It can be fabricated in to desired shape by hot processing and
sintering the polymer powder
Characteristics / Properties of Teflon :
It is transparent in nature.
Excellent resistance to most of the chemicals and solvents.
Low coefficient of friction.
Good heat resistance and non-sticking properties.

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Applications of Teflon:
1.Chemical processing and petrochemical sectors: used
for vessel linings, seals, spacers, gaskets,well-
drilling parts and washers.
2. Laboratory applications: Tubing, piping, containers
and vessels due to resistance to chemicals.
3. Electrical industry: used as an insulator in the form
of spacers, tubing etc.
4. Virgin PTFE had been use in the pharmaceutical,
beverage, food and cosmetics industries.
5. Semiconductor sector: used as an insulator in
capacitors and in the chip manufacturing process.

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Various Types of Thermosetting Plastic Materials
1.Polysters:-
Unsaturated polyesters (UPR) are thermosetting resins.
They are used as casting materials, fiberglass laminating resins and non-metallic auto-
body fillers.
Fiberglass reinforced unsaturated polyesters find wide application in bodies of yachts
and as body parts of cars.
Characteristics / Properties of Polysters :
Polyester and nylon have similar properties.
It is very strong fibre, so garments made from polyester fibres last longer than the
ones made from natural fibres.
Good resistant to wrinkles.
Not a good absorbent of water, Therefore polyester clothes dry faster.
Highly abrasion and moth resistant.
Resistant to ordinary chemicals and biological agents.

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Applications of Polyester Fibres : Polyester is used in making
Textiles, sarees, dress materials, and curtains.
Blended textiles with natural fibres. For example, when terylene is mixed with cotton,
it is called terrycot and with wool, it is called terrywool.
Water hoses for fire-fighting operations.
Conveyor belts, paints, joining and repair work Safety helmets, fibre glass boat and
automobile components..

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Summary
In this lesson, We have learned
Polymeric Materials, Polymers- types, characteristics
1. Thermoplastics plastics
2. Thermosetting plastics
3. Elastomers -Rubber

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Class: SYME
Lecture 13: Thermosetting Plastic, Rubber,
Engineering Material –Types
& application

Topic to be covered
•Thermosetting Plastic materials
•Characteristics and uses of ABS, Acrylics. Nylons and Vinyls,Epoxides, Melamines and
Bakelites
•Rubbers: Neoprene, Butadiene, Buna and Silicons – Properties and applications.

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2. Epoxies:-
Epoxy or polyepoxide is a thermosetting polymer formed from reaction of an epoxide
"resin" with polyamine "hardener".
Epoxy has a wide range of applications, including fiber-reinforced plastic materials and
general purpose adhesives.
Characteristics / Properties of Epoxies :
It has good adhesive and electrical properties.
It is very tough, with excellent hardness.
High heat resistance.
Good corrosion resistance.
Good thermal shock resistance
It has good resistance to solvent and chemicals except chlorinated hydrocarbons and
ketons.

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Applications of Epoxies :
1. It is used in the construction of aircraft, automobiles, bicycles, boats, golf clubs, skis,
snowboards, and other applications where high strength bonds are required.
2. It is also used in protective coatings, electrical moldings, sinks, used with fibre glass
laminates.
3. It is used in electrical moldings.

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3. Melamine :-
Melamine is combined with formaldehyde to produce melamine resin, a very durable
thermosetting plastic used in Formica, and melamine foam, a polymeric cleaning
product.
Characteristics / Properties of Melamine :
More resistance to chemical.
High heat and moisture resistance.
It is scratch free and more expensive.
Good electrical properties.
High dimensional stability.
It is affected by ultra violet light.
High hardness.

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Applications of
Melamine :
1. floor tiles
2. Kitchenware
3. fire retardant fabrics,
4. commercial filters,
5. glue for plywood,
6. switches, plugs
housewares,
7. surface coatings and
decorative laminates.

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4. Bakelite (Phenol Formaldehyde) :-
This is obtained by condensation polymerisation of phenol and formaldehyde in an
acid or alkaline medium
Characteristics / Properties of Bakelite (Phenol Formaldehyde) :
It is easily moulded.
It is hard and rigid.
Good resistance to heat, water, most chemical and solvents.
It has good electrical insulations and mechanical strength.
Applications of Bakelite :
1. Vacuum cleaner parts,
2. Handle, knob for domestic appliances,
3. Paints and adhesive,
4. Molded disc brake cylinders, electrical plugs and switches and parts for electrical
irons.

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Applications of Bakelite :
5. Films or sheets for packaging,
6. Shower curtains,
7. Unbreakable bottles, pipes, drinking glasses, and
8. Insulation for wire and cable

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Rubber
1.Natural Rubber
Natural rubber is a polymerized form of isoprene.
The polyhedrocarbon chains consist of 2000 to 3000 monomer links.
The polymerization occurs by a biochemical reactions in which a particular type of
enzyme acts as a catalyst agent.
The main source of natural rubber is the HeveaBrasiliensis tree which is mostly grows
in Srilanka, Malaysia, Indonesia, Thailand and India.
The natural rubber also found in the juice of many other plants such as shrub guayule.
However, heveabrasiliensis is the best source of milky juice called rubber lathex.
Natural rubber has excellent physical properties, good absorption resistance, high
strength and low cost.
Natural rubber is used for tire and tubes, heels and soles and gaskets.

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Rubber
2.Synthetic Rubber.
Rubber produced by artificial chemical process is known as synthetic rubber.
It has properties similar to natural rubber.
It is available in various names like butyl rubber, silicon rubber, neoprene rubber etc.

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Rubber
3.Neoprene (Polychloroprene) Rubber
Neoprene was developed in the 1930s, and has the distinction of being the first
commercial synthetic rubber.
It is chemically and structurally similar to natural rubber, and its mechanical
properties are also similar.
Properties of Neoprene rubber :
Neoprene rubber has better resistance to oil, grease, and petroleum solvent as
compare to natural rubber.
Good mechanical strength and physical properties.
It has better resistance to heat and light.
This rubber has a perfect balance of mechanical properties and fatigue resistance.
It can use for a large temperature range.

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Rubber
Applications / uses of
Neoprene rubber :
1. Motor belts,
2. Gaskets,
3. Oil seals,
4. LPG hoses,
5. Gloves, apron,
6. Solid tyres,
7. Wire and cable coatings
etc.

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Rubber
4.Styrene Butadiene Rubber (SBR) :
Those elastomers,sometime also called Buna S or GR-S are copolymers of butadiene
and styrene.
They are similar in many ways to the natural rubber, and Fibres
Properties of Styrene Butadiene Rubber (SBR) :
It has similar chemical and physical properties like natural rubber.
It has better abrasion resistance.
It has poor fatigue resistance.
Heat resistance is better than natural rubber.
Low temperature flexibility and tensile strength are less than that of natural rubber.
This type of rubber is usually very weak unless reinforcing fillers are incorporated,
With suitable fillers, this becomes a strong rubber.

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Rubber
Applications of
Styrene Butadiene
Rubber (SBR) :
1. It is used in
automobile tyres,
2. Foot wear,
3. Cable insulation,
4. Moulded articles,
5. Hose pipes and
conveyor belts,
6. Floor tile,
mechanical goods etc.

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Rubber
5.Silicone Rubber :
This is a unique synthetic elastomer which is made from a cross-linked polymer that is
reinforced with silica.
The characteristic of this rubber is such that it provides the perfect balance of
mechanical and chemical properties which is required in today's most demanding
applications.
Properties of Silicone Rubber :
Resistance to wide temperature range.
It offers excellent resistance to extreme temperature 2500 ºC to 800 ºC.
Better oil and water resistance.
The tensile strength, tear strength, elongation and compression set are far superior to
conventional rubbers.
Resistant to steam.
Glows in the dark.

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Rubber
Properties of Silicone Rubber :
Electrically conductive.
Resistant to oil, chemical, acid, gas resistance.
Low smoke emission and flame retardant.
Applications of Silicone Rubber :
1. It is used in surgical devices,
2. Gaskets, seals,
3. Insulation to wire, cable,
4. tubes,
5. Gas mask,
6. Nuclear power cable,
7. Seal for expansion joints,
8. Rubber rolls etc.

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Engineering Materials
1.Ceramic
Ceramic materials are defined as those containing phases that are compounds of
metallic and non-metallic elements.
Most ceramic phases, like metals, have crystalline structure.
Ceramic crystals are formed by either a pure ionic bond, a pure covalent bondor by
bond that possess the ionic as well as covalent characteristics.
Some common examples of ceramics materials are : Silica, glass, refractory, silicon
carbide, ferrites etc.
Properties of Ceramic :
They are hard brittle material.
Resistance to corrosion and high temperature strength.
Resistant to plastic deformation.
The compressive strength is more than the tensile strength.
They are bad conductor of electricity.

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Properties of Ceramic :
Poor machinability.
The ceramic materials possess a very low thermal conductivity.
It is highly resistant to all chemicals except hydrofluoric acid.
Applications of Ceramic :
1. Aerospace : space shuttle tiles, thermal barriers, high temperature glass windows,
fuel cells
2. Consumer uses : glassware, windows, pottery,Corning¨ ware, magnets, dinnerware,
ceramic tiles, lenses, home electronics, microwave transducers
3. Automotive : catalytic converters, ceramic filters, airbag sensors, ceramic rotors,
valves, spark plugs etc
4. Medical : orthopaedic joint replacement, dental restoration, bone implants
5. Other Industries : bricks, cement, membranes and filters, lab equipment

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2. Abrasive :
Abrasive are substance that are employed to wear off or rub down the object, in order
to give them desired size, shape of finish.
Abrasive particles held together by a bonding material comprise the cutting agents in
grinding wheels.
Abrasive are used for operation such as scratching, grinding, cutting, rubbing etc.
Some common example of abrasive materials are :Aluminium oxide, silicon carbide,
zirconia carbide,ceramic,emery, sand, glass powder etc.
Classifications of abrasive :
1. Natural abrasive
2. Artificial (synthetic) abrasive

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Classifications of abrasive :
1. Natural abrasive : A hard material found in the earth that is used to shape other
materials by grinding or abrading.
Eg diamond, corundum, emery, granite, quartz, sand etc.
2. Artificial (synthetic) abrasive : Synthetic abrasives, are the product of considerable
processing of raw materials or chemical precursors.
Eg silicon carbide, synthetic diamond, alumina and boron carbide etc.
Properties of abrasive :
High temperature resistance.
High electrical resistivity. (Although some ceramics are superconductors)
Broad range of thermal conductivity.
High hardness.
Good chemical and corrosion resistance.

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Properties of abrasive :
Low cost of raw materials and
fabrication for some ceramics.
Good appearance control through
surface treatments, colorization etc.

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3. Adhesive.
A substance used to join two or more parts so as to form a single unit is called
adhesive.
Adhesives have a wide range of properties which make them suitable for a variety of
manufacturing situations.
Classifications of adhesive :
1. Natural adhesives
2. Synthetic adhesives
3. Drying adhesives
4. Contact adhesives
5. Hot adhesives :

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1. Natural adhesives :
Natural adhesives are made from organic source such as vegetable matter, starch,
natural resins or from animals.
They are often referred to as bio-adhesives.
One example is a simple paste made by cooking flour in water.
Animal glues are traditionally used in book binding, wood joining, and many other
areas but now are largely replaced by synthetic glues.
2. Synthetic adhesives :
Synthetic adhesives are based on elastomers,thermoplastics, emulsions, and
thermosets.
Examples of thermosetting adhesives are: epoxy, polyurethane, cyanoacrylate and
acrylic polymers.

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3. Drying adhesives :
There are two types of adhesives that harden bydrying,solvent based adhesives and
polymer dispersion adhesives, also known as emulsion adhesives.
Solvent based adhesives are a mixture of ingredients (typically polymers) dissolved in
a solvent.
White glue, contact adhesives and rubber cements are members of the drying
adhesive family, As the solvent evaporates, the adhesive hardens.
4. Contact adhesives :
Contact adhesives are used in strong bonds with high shear-resistance like laminates, such as
bonding Formica to a wooden counter, and in footwear, as in attaching outsoles to uppers.
Contact adhesives must be applied to both surfaces and allowed some time to dry before the
two surfaces are pushed together

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5. Hot adhesives :
Hot adhesives, also known
as hot melt adhesives, are
simply thermoplastics
applied in molten form
which solidify on cooling to
form strong bonds between
a
wide range of materials.

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4. Asbestos :
Asbestos is a fibrous material substance that is used primarily as a fireproofing and
insulation material in buildings, homes, and industrial installations.
Asbestos is the commercial name given to certain types of fibrous materials which are
group of minerals; occur naturally as masses of strong flexible fibers that can be
separated in to thin threads.
They are silicates of varying composition.
Silica is combined with such bases as magnesium, iron,ncalcium, sodium and
aluminium.
Asbestos is a general term used to described six fibrous minerals, namely
1. Chrysotile 4. Anthophyllite
2. Amosite 5. Actinolitr
3. Crocidolite 6. Tremolite

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Properties of Asbestos :
It has got insulating properties and resistance to all atmospheric agents and
pollutants.
It does not react with other chemicals.
It has fire resistant.
Alkaline, acid and water resistant.
Has no detectable smell.
Hard, it's amazingly resistant to scratch.
Applications of Asbestos : Asbestos is used in the manufacture of
1. Cement pipes, cement wall board,
2. Boiler insulation, fire proofing materials, insulators,
3. Brake shoes,
4. Cooling towers,
5. Vinyl wall coverings, Vinyl tiles,

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Applications
of Asbestos :
Asbestos is
used in the
manufacture
of
6. Pipe
insulation,
7. Putties,
adhesives,
8. Fire proof
textiles,
9. Gaskets etc.

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Summary
•Thermosetting Plastic materials
•Characteristics and uses of ABS, Acrylics. Nylons and Vinyls,Epoxides, Melamines and
Bakelites
•Rubbers: Neoprene, Butadiene, Buna and Silicons – Properties and applications.
•Asbestos - Properties and applications

58

Class: SYME
Lecture 14: Advanced Engineering Materials

Topic to be covered
•Composite Materials - properties and applications of Laminated and Fibre
•Advanced Engineering Materials Properties and applications of Nano

62
5. Cork :
Cork is the outer bark of a oak tree found in Spain, Portugal and Africa.
It is used in composite form and melded in blocks under heat and pressure.
Properties of Cork :
It has good stability andvery lightweight.
Cork is impermeable to both liquids and gases, giving it superior sealing capabilities.
It has low conductivity of heat.
It has ability to absorb sound or vibrations.
It has high coefficient of friction.
It has shown a remarkably high tolerance to heat.
Good insulator.

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Applications of cork :
1. Use for wine bottle
closures,
2. Fishing floats,
3. Handles of various
parts,
4. Floor tiles,
5. Freezer cabinets,
6. Roof insulations and
insulations for cold
storage.

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6. Thermocole
Thermocol is a restructured chemical bonding of polystyrene (a synthetic petroleum
product) molecules and developed a substance named stretch polystyrene.
These thermoplastic granules are expanded through application of steam and air.
Expanded granules become much larger in size but remain very light.
Thermocol is a good resister of cold and heat but since it is a petroleum product it
dissolves in any solvent of petroleum.
Properties of Thermocol :
It has excellent insulating properties.
It can be cut easily with simple tools like knife or a saw.
It has a high resistance to moisture, adequate structural strength

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Properties of Thermocol :
It has excellent dimensional stability makes
it easy to use.
It has snow white in colour and odourless.
It is very light in weight.
Fungus resistance.
Applications of Thermocol :
1. Used in packaging,
2. Various decorative articles,
3. Insulators and material for pattern making.
4. Moulded packaging for electrical and
electronics item to protect from shock.

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7. Glass Wool
Glass wool is an insulating material made from fiberglass, arranged into a texture
similar to wool.
Glass wool is made by direct melting.
Air or steam jets are used, but the conditions are such that attenuation is more violent
and haphazard.
Glass wool is produced in shorter fibers are produced, in a wider range of diameter,
with different thermal and mechanical properties.
Properties of Glass Wool :
It has good thermal and cold insulating properties.
Excellent fire resistant properties
It has low density.
It is non-combustible, non-toxic, and resistant to corrosion.

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Properties of Glass Wool :
Low thermal conductivity.
Stable chemical property, and low moisture absorption
rate due to its excellent hydrophobicity.
Applications of Glass Wool :
1. Glass wool provides excellent thermal insulations.
2. Sheets and panels that can be used to insulate flat
surfaces.
3. Ceiling tiles,
4. Curtain walls as well as ducting.
5. It is also used to insulate piping and for sound proofing.
6. Used in blankets, blocks and boards.
7. It is used in space suit and space capsules

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Composite Materials
Introduction to Composite Materials
A composite material is a combination of two or more materials bonded together
having combined properties of constituents are called composites.
In its simplest form composite consists of two independent and dissimilar materials.
The composite material is generally better than any of the individual components as
regards their strength, heat resistance or stiffness.
Composites include the following :
(i) Multiphase metal alloy
(ii) Ceramics
(iii) Polymers

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Composite Materials
Classifications of Composite Materials
The composite materials are classified as
follows:
1. Particle reinforced :
a. Large particle
b. Dispersion strengthened.
2. Fibre reinforced :
a. Continuous (aligned)
b. Discontinuous (short)
i) Aligned.
ii) Randomly oriented.
3. Structural :
a. Laminates
b. Sandwich panel

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Composite Materials
1. Fibre reinforced composite :
It consist of three ingredients namely matrix, fibre
and interface.
Matrix is used to bind together the fibres and to
protect their surface from damage or chemical
attack.
Matrix separates individual fibre and prevents
brittle cracks.
Metallic fibre or wires, non metallic and whisker
are the material used for fibre.
The strength of fibrous composites is determined
by the strength of the fibres and the type of the
bond between the fibre and matrix.

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Composite Materials
1. Fibre reinforced composite :
The strength and other properties of these
composites are influenced by the following :
(i) The arrangement or orientation of the fibres.
(ii) The fibres concentration.
(iii) The fibre distribution.
Some important fibre composites are :
Polymer matrix composites.
Glass fibre reinforced polymer (GFRP) composites
Carbon fibre reinforced polymer (CFRP) composites
Aramid fibre reinforced polymer (AFRP)composites

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Composite Materials
Some important fibre composites are
Metal matrix composites (MMC)
Ceramic -matrix composites (CMC)
Carbon carbon composites (CCC)
Hybrid composites
Properties of fibre composites :
1. High stiffness.
2. High specific strength
3. High toughness
4. Corrosion resistance
5. Oxidation resistance and
6. Resistance to electrical and thermal
conductivity.

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Composite Materials
Applications of
fibre composites :
1. Used in
aerospace
2. Used in marine
applications
3. Used in
furniture.
4. Used in
automobile bodies
5. Used in
bathtub, helmets
etc

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Composite Materials
2. Laminates :
Product obtained by two or more laminations or layer of different or same materials
bonded to each other processing improved properties are called laminated composites.
Plywood is a laminated composite of thin layer of wood in which successive layers
have different orientations of the grain or fibre.
The result is a more or less isotropic composite sheet which is weaker in
any direction.
The galvanised sheet, aluminium copper alloy with aluminium claddingare some of the
example of these types of products which give better properties, like corrosion
resistance, surface hardness,impact resistance and heat transfer etc compared to
conventional materials.

75
Composite Materials
characteristics of composites
1. Specific strength This is simply the rigidity or hardness of a material with regard to its
weight.
2. Expense Many composites can be manufactured with less cost than their traditional
metal counterparts.
3. Application Because composites are composed of two or more "phases", they can be
formulated to meet the needs of specific application with considerable ease.
4. Processability -Metal processing requires high amounts of thermal energy (heat).

76
Advanced Engineering Materials
Nanomaterials
Nanoscale materials are defined as a set of substances where at least one dimension
is less than approximately 100 nanometers.
A nanometer is one millionth of a millimeter approximately 100,000times smaller
than the diameter of a human hair.
Nanomaterials are of interest because at this scale unique optical, magnetic,
electrical, and other properties emerge.
Uses of Nanomaterials
These emergent properties have the potential for great impacts in electronics,
medicine, and other fields.
Some nanomaterials occur naturally, but of particular interest are engineered
nanomaterials (EN),which are designed for, and already being used in many commercial
products and processes.

77
Uses of Nanomaterials
They can be found in such things as sunscreens, cosmetics, sporting goods, stain-
resistant clothing, tires,electronics, as well as many other everyday items, and are used
in medicine for purposes of diagnosis,imaging and drug delivery
Classification of Nanomaterials :
Nanomaterials have extremely small size which having at least one dimension 100 nm
or less.
Nanomaterials can be nanoscale in one dimension (eg. surface films), two dimensions
(eg. strands or fibres), or three dimensions (eg. particles).
They can exist in single, fused, aggregated or agglomerated forms with spherical,
tubular, and irregular shapes.
Common types of nanomaterials include nanotubes, dendrimers, quantum dots and
fullerenes.

78
Classification of Nanomaterials :
Nanomaterials have applications in the field of nano technology, and displays different
physical chemical characteristics from normal chemicals (i.e., silver nano, carbon
nanotube, fullerene, photocatalyst,carbon nano, silica).
According to Siegel,Nanostructured materials are classified as Zero dimensional, one
dimensional, two dimensional, three dimensional nanostructures

79
Smart materials

80
Smart materials
Smart materials called also intelligent or responsive materials, are designed materials
that have one or more properties that can be significantly changed in a
controlled fashion by external stimuli, such as stress,temperature, moisture, pH, electric
or magnetic fields,light, or chemical compounds. Smart Materials are the
Smart Materials are the basis of many applications, including sensors and actuators, or
artificial muscles, particularly as electrically activated polymers (EAP's)
Types of Smart materials
Piezoelectric materials are materials that produce a voltage when stress is applied.
Since this effect also applies in the reverse manner, a voltage across the sample will produce
stress within sample.
Suitably designed structures made from these materials can therefore be made that bend,
expand or contract when a voltage is applied.

81
Shape-memory alloys and shape-memory polymers are materials in which large
deformation can be induced and recovered through temperature changes or stress
changes (pseudo elasticity).
The shape memory effect results due to respectively martensitic phase change and
induced elasticity at higher temperatures.
Photovoltaic materials or optoelectronics convert light to electrical current.
Electroactive polymers (EAP's) change their volume by voltage or electric fields
Magnetostrictive materials exhibit change in shape under the influence of magnetic
field and also exhibit change in their magnetization under the
influence of mechanical stress.
Magnetic shape memory alloys are materials that change their shape in response to a
significant change in the magnetic field.
Smart inorganic polymers showing tunable and responsive properties.

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pH-sensitive polymers are materials that change in volume when the pH of the
surrounding medium changes.
Temperature-responsive polymers are materials which undergo changes upon
temperature.
Halochromic materials are commonly used materials that change their colour as a
result of changing acidity.
Photomechanical materials change shape under exposure to light.
Polycaprolactone (polymorph) can be molded by immersion in hot water.
Self-healing materials have the intrinsic ability to repair damage due to normal usage,
thus expanding the material's lifetime.
Dielectric elastomers (DEs) are smart material systems which produce large strains (up
to 500%) under the influence of an external electric field.

83
Magneto caloric materials are compounds that undergo a reversible change in
temperature upon exposure to a changing magnetic field.
Thermoelectric materials are used to build devices that convert temperature
differences into electricity and vice versa.
Chemo responsive materials change size or volume under the influence of external
chemical or biological compound.

84

85
Summary
•Composite Materials - properties and applications of Laminated and Fibre
•Advanced Engineering Materials Properties and applications of Nano

86

Chapter 5 Mechanical Engineering Materials 22343

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Chapter 5 Mechanical Engineering Materials 22343