Unit 2_Plastics.pdf

Plastics?
Plastics & Plasticity?
Why plastic exists?
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Introduction
Plastic means “pliable and easily shaped.”
Plastic also means polymeric material.
Plastics = Polymers = chain of monomers
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Introduction
• Plastic -
• An engineering material
• Most versatile material on earth
• Almost all of the products we use in our daily lives contain
plastics.
• They are made of polymers.
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Plastics
Polymerization
Polymer
Monomer
Molecule
Atom

Plastics – Monomers & Polymers
• A monomer is a molecule that consists a primary chemical,
mostly organic, forming chemical bond.
• They react together with other monomer molecules to form a
larger monomer chain or three-dimensional network in a
process called polymerization, resulting in Polymers.
• Polymer means ‘many parts’.
• Polymers – Natural, Synthetic & Semi-synthetic.
• Plastic is a type of polymer resulting from polymerization.
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Plastics – Monomers & Polymers
Polymers
Natural
Occur naturally and are found in plants and animals
E.g. - proteins, starch, cellulose, and rubber.
We also have biodegradable polymers called
biopolymers.
Synthetic
Man-made polymers
Plastic is the most common and widely used synthetic
polymer.
E.g. - nylon, polyether’s etc.
Semi-
synthetic
Derived from naturally occurring polymers and undergo
further chemical modification.
E.g. - cellulose nitrate, and cellulose acetate.
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Types of Polymeric materials
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Plastics – Polymer structures
1. Linear – long-chain molecules separated
from each other
2. Branched chain - branches of monomers
added on to the linear chain of
macromolecules
3. Cross-linked – chains adjacent to each
other linked together restricting the
movement between chains & altering the
mechanical properties
4. Networking – formed by tri- or tetra-
functional monomers
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Plastics – Polymerization
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Process used to
combine
monomers to form
a polymer
It improves the
properties like
strength, rigidity &
elasticity

Plastics – Polymerization methods
Addition –
• Similar or different molecules join
together to form a polymer.
• A reaction that yields a product
which is an exact multiple of the
original monomeric molecule.
• Commonly used in the manufacture
of flexible films and squeeze bottles
• E.g.- polythylene, polypropylene,
polyvinylchloride, polystyrene,
polyacrylates, etc.
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Co-polymerization –
• A type of addition polymerization where simultaneous polymerization of two or
more chemically different monomers takes place resulting in the formation of a
polymer containing both monomers linked in one chain.
• E.g.- vinyl chloride acetate, butadiene-styrene etc.
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Condensation –
• In this, the reaction between functional monomer molecules leading to the
formation of a polymer with the elimination of some small weight molecules
such as water, HCl, etc.
• The most common is Nylon formed from hexamethylene diamine and adipic
acid. Phenol formaldehyde resin (Bakelite) is another example.
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Plastic
• an organic substance which consists natural or synthetic binders or resins
with or without moulding compounds/fillers, plasticizers and pigments which
can be moulded to any desired form when subjected to heat and pressure
in the presence of a catalyst.
or
• compounds of carbon with other elements viz. hydrogen, nitrogen &
oxygen.
or
• a synthetic materials made from wide range of organic polymers like
polyethylene, polyvinylchloride, nylon, etc, that can be moulded into shape
while soft and then set into a rigid or slightly elastic form.
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Timeline of Plastic Industry
Natural plastic -
horns, ivory,
tortoise shell,
amber, rubber
and shellac.
In 1862,
Alexander Parkes
gave Parkesine
In 1869, John
Wesley Hyatt gave
Celluloid
In 1907, Leo
Hendrik
Baekeland gave
Bakelite
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Parkesine – Semi-synthetic – Also cellulose nitrate, nitro-cellulose derived
from cotton fibres dissolved in nitric and sulphuric acids then
mixed with vegetable oil.
Celluloid – Semi-synthetic – Cellulose and alcoholized camphor
Bakelite – Synthetic - Phenol-formaldehyde resin

Classification of Plastics
• Thermo-plastics
• Thermo-setting
Behavior with respect to
heating
• Homogeneous
• Heterogeneous
Structure
• Rigid
• Semi-rigid
• Soft
• Elastomers
Physical & mechanical
properties
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• Plastics composed only of carbon atoms exhibits
homogeneous structure.
Homogeneous Plastics
• Plastics composed of carbon, oxygen, nitrogen …etc. exhibits
heterogeneous structure.
Heterogeneous Plastics
• having high modulus of elasticity & retain their shape under
exterior stresses applied at normal or moderately increased
temperature.
Rigid Plastics
• Having medium modulus of elasticity & elongation occurs under
pressure completely disappears when pressure is removed.
Semi-rigid Plastics
• Having low modulus of elasticity & elongation occurs under
pressure disappears slowly when pressure is removed.
Soft Plastics
• Soft & elastic materials with low modulus of elasticity.
• They deform under load at room temperature & return to its
original shape, when load is released.
Elastomers
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Thermo- Plastics & Setting
# Thermo-Plastics Thermo-Setting
1 Plastics which become soft when heated
& hard when cooled.
Plastics which become rigid when molded at
suitable pressure & temperature.
2 No chemical bonding occurs during
curing.
Cross-linking of polymers occurs during curing.
3 Having reversible bonding Having irreversible bonding
4 This characteristic allows them to be
remolded and recycled without negatively
affecting the material’s physical properties.
The process eliminates the risk of the product
remelting when heat is applied.
This type of plastic passes through thermo-
plastic stage.
5 Also known as Heat non-convertible group Also known as Heat convertible group
6 Ideal for the manufacture of pipes, ropes,
belts, insulators, and adhesives
Ideal for high-heat applications such as
electronics and appliances.
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7 These are formed by addition
polymerization and have long
chain molecular structure.
They are synthesized by condensation
polymerization.
8 Thermoplastic is processed by injection
moulding, extrusion process, blow
moulding, thermoforming process, and
rotational moulding.
Thermosetting Plastic is processed by
compression moulding, reaction injection
moulding.
9 Thermoplastics have low melting points
and low tensile strength.
Thermosetting plastics have high melting
points and tensile strength.
10 Tougher, less brittle, have excellent
damage control and impact resistance,
high strength, shrink-resistance and easy
bendability.
Enhanced chemical resistance, heat
resistance and structural integrity, durable,
strong & hard, more brittle
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11 Efficiently serve various low-stress
applications like high-stress mechanical
parts or plastic bag.
Often used for sealed products due to their
resistance to deformation.
12 Also use as Reusable plastic containers,
diapers, ropes, carpets, sanitary pads,
piping systems, car batteries, electrical
cable insulation, and gas and liquid filters
The principal uses are in electrical
equipments, plugs, sockets, switches, ash
trays, knobs, handles, etc.
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Pros
1. Highly recyclable
2. Aesthetically-superior finishes
3. High-impact resistance
4. Remolding/reshaping capabilities
5. Chemical resistant
6. Hard crystalline or rubbery surface
7. Eco-friendly manufacturing
1. More resistant to high temperatures
2. Highly flexible design
3. Thick to thin wall capabilities
4. Excellent aesthetic appearance
5. High levels of dimensional stability
6. Cost-effective
Cons
1.Generally more expensive than thermoset
2. Can melt if heated
1. Cannot be recycled
2. More difficult to surface finish
3. Cannot be remolded or reshaped
Types
HDPE, LDPE, PVC, Polystyrene,
Polypropylene, Acrylo-nitrile (Nylon), ABS,
Melamine Formaldehyde, Poly Vinyl Acetate
(PVA), Acrylic (Perspex), Elastomers
Epoxy Resin, Polyester Resin, Glass
Reinforced Plastic, Carbon Fibre Plastic,
Melamine Formaldehyde
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Plastic - Constituents
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1. Base of the plastic – resins or binders
2. Moulding compounds – additives, as essentials to achieve desired
properties
Resins or binders
Thermo-plastic
Thermo-setting
Moulding compounds
Catalysts
Fillers
Hardeners
Lubricants
Pigments
Plasticizers
Solvents

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#
Moulding
compounds
Function Example
1 Catalysts Added to assist & accelerate the hardening of resin
Ester acts as catalysts for
urea formaldehyde
2 Fillers
Inert materials imparting strength, hardness & other
properties. Type – Fibrous, Laminated, Powder
3 Hardener Added to increase the hardness of resin
Hexamethylene tetramine
acts as hardener for phenol
formaldehyde
4 Lubricants
Applied on the surface of the moulds to avoid sticking of
plastic on the moulds
Graphite, paraffin, wax etc.

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#
Moulding
compounds
Function Example
5 Pigments
Addition of dyes & pigments helps as filler & imparting
color
Zinc oxide, barytes etc.
6 Plasticizers
Organic compounds which are oily in nature & have low
molecular weight.
Improves plasticity & impart softness & flexibility & also
acts as lubricant.
Camphor, triacetin, tributyl
phosphate…etc.
7 Solvents Added to dissolve plasticizers
Alcohol added to dissolve
camphor in cellulose nitrate.

Plastic - Fabrication
• The method used for fabrication of commercial articles from plastics
depends primarily on the type, resin used, shape, size and thickness
of the articles.
• Commonly used fabrication methods.
1. Blowing
2. Calendaring
3. Casting
4. Laminating
5. Moulding
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Blowing Fabrication
• Process used to manufacture hollow items – jars, bottles, toys etc.
• Air pressure or vacuum are employed in this method of moulding to
force the softened plastic powder into the mould.
• Used for HDPE,LDPE, PVC,PP etc.
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Calendaring Fabrication
• Process is used to prepare plain flat sheets.
• Consists - 4 rollers-3 hot & 1 cold in the end.
• Artistic design may be provided on rollers.
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Casting Fabrication
• Process is used to prepare cellulose plastic.
• The plastics are moulded without application of pressure. The resin is
melted and poured into mould. The cast plastic is not so smooth just
after casting, so they are polished.
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Laminating Fabrication
• Process is used with thermo-setting resins which are
applied on the product to be laminated viz. paper,
cloth, wood, fibre, glass, etc.
• Then the product is subjected to heavy pressure by
allowing them through rollers to form the plastic
layer.
• Thickness of sheet varies from 0.12-15mm.
• Used for ornamental & decorative purposes.
• The laminated plastics exhibit improved mechanical
and electrical properties.
• Vinyl resin is most suitable for lamination.
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Moulding Fabrication
• Most common process – raw material placed in mould & then heated.
• Moulding method varies as per the article to be prepared.
• Types of Moulding – Compression, Extrusion, Injection, Jet &
Transfer
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Compression Moulding
• Employed for both thermoplastics and
thermosetting plastics
• The moulds used are usually heated & plastic
material is filled in the mould cavity.
• With hydraulic pressure & under heating
temperature the chemical reaction is
completed. Finally curing is done by heating
(thermosetting plastics) or by cooling
(thermoplastics).
• After curing is complete, mould is opened and
moulded material is taken out.
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Extrusion Moulding
• Adopted for thermoplastics resins.
• The resin powder fed through hopper in the inlet end of the revolving
screw.
• As the extruder rotates it has a mixing, smearing, and frictional
heating action which changes the dry granular charge into a soft
plastic mass before it reaches the end of the screw.
• At the outlet end, the material is heated & is extruded or forced
through a nozzle into the moulds.
• Moulds are cooled with air jets or water baths.
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Extrusion Moulding
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• Used for continuous moulding of thermoplastic materials into articles
of uniform cross-section such as tubes, ribbons, sheets, pipes, rods,
strips, electric cables, etc.

Extrusion Moulding
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Injection Moulding
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• Used for thermoplastic
resins for small size
articles for large scale
preparation.
• The mould is kept cold
to allow the hot plastic
to cure and acquire the
shape. Half of the
mould is opened to
cause ejection of the
finished article.

Transfer Moulding
• It is injection moulding when applied to
thermosetting resins.
• In this, the mould are also heated before
plastic material is injected through
nozzle. Thus the resins are heated in
two chambers – cylinder & moulds.
• The pressure on mould is maintained till
the chemical action is complete to
prepare article.
• Intricate machine parts are moulded by
this method.
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Jet Moulding
• Employed for both thermoplastics and thermosetting plastics
• The plastic material is heated moderately and allowed to pass
through nozzle which is preheated to a high temperature.
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Plastic Properties
1. Can be moulded to any desired shape or size and
have high tensile and compressive strengths.
2. Easy to work upon.
3. Light in weight and a few varieties are glossy like
glass.
4. Not attacked by insects and fungi.
5. Available in desired colors, texture & appearance -
transparent, colored, opaque, translucent.
6. Require a little maintenance.
7. Good electrical insulators and have low thermal
conductivity.
8. Shock absorbing material.
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Plastic Properties
9. Can be sawn, drilled and punched and
welded easily.
10. High strength to weight ratio.
11. High resistance to weathering conditions.
12. Corrosion resistance.
13. Decorative surface effect—painting or
polishing of the surface is not required.
14. High refractive index.
15. Some varieties are as hard as steel.
16. Withstands moisture, oil and grease well –
Chemical resistant.
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Plastic Properties
17. Durable
18. Inflammable or fire-resistant.
19. High coefficient of thermal expansion (about
ten times of steel).
20. Deterioration under prolonged exposure to
sun’s ultra violet rays.
21. Low manufacturing cost, hence cheap.
22. Dimensional stability
23. Lack ductility
24. Can be recycled, upcycled & reused.
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Plastic Applications
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Plastic Applications
1. Sanitary fixtures
2. Electrical conduits
3. Roofing sheets
4. Decorative laminates & moldings
5. Films for water-proofing, damp-
proofing & concrete curing
6. Floor tiles, floor coverings
7. Foams for thermal insulation
8. Lighting fixtures
9. Overhead water tanks
10. Paints & varnishes
11. Pipes
12. Roof lights
13. Safety glass
14. Wall tiles
15. Water-resistant adhesive
16. Formwork
17. Furniture
18. Temporary structures
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Types of Plastics
1. PE – LDPE & HDPE
2. PVC – UPVC, CPVC…etc.
3. PS
4. Acrylic
5. PC
6. Rubber – EPDM, Neoprene
7. Bakelite
8. Nylon
9. GFRP
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Polyethylene (PE)
• Also known as polythene or polyethene.
• Usually have a linear structure and are
known to be addition polymers
• Primary application – Packaging - plastic
bags, bottles, plastic films, containers, and
geomembranes.
• General formula of polyethylene - (C2H4)n
• Mostly, polyethylene are thermoplastic,
however, some modified polyethylene
plastics exhibit thermosetting properties.

Polyethylene (PE)
• Can be classified into several different types based on the density of
the plastic and the degree of branching in its structure.
• The type of branching and the extent of branching has a direct
impact on the mechanical properties of the plastic.
• Therefore, different types of polyethylene exhibit different mechanical
properties.
• Mainly classified into three types – LDPE, LLDPE and HDPE
• Level of Crystallinity strongly affects the properties. Increasing
the degree of crystallinity increases hardness and density.

Polyethylene (PE)
# LDPE HDPE
1 Low Density Polyethylene High Density Polyethylene
2 A thermoplastic made from the monomer ethylene/petroleum
3 A soft, flexible, tough & lightweight material A rigid, strong & relatively less lightweight
material
4 Has good chemical and impact resistance
and is easy to fabricate and form.
Easily Meltable and Moldable, Corrosion
Resistance, Large Strength to Density Ratio,
Easily Recycled
5 Used to make many thin, flexible
products like plastic bags for dry-cleaning,
newspapers, bread, bubble wrap, frozen
foods, fresh produce and garbage. Shrink-
wrap and stretch film are also made out
of LDPE, as well as coatings for paper milk
cartons and disposable beverage cups.
Most versatile plastic materials used in a wide
variety of applications including plastic bottles,
milk jugs, shampoo bottles, bleach bottles,
cutting boards, buckets, park benches and
piping.

LDPE-Low Density Polyethylene
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HDPE-High Density Polyethylene

PVC- Poly Vinyl Chloride or Vinyl
• Economical and versatile thermoplastic polymer
• Widely used in building and construction industry to
produce door and window profiles, pipes (drinking
and wastewater), wire and cable insulation, medical
devices, etc.
• World’s third largest thermoplastic material by
volume after PE & PP.
• A white, brittle solid material available in powder
form or granules.
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PVC - Poly Vinyl Chloride
• Also hard & rigid plastic, is resistant to chemicals and weathering,
making it desired for building & construction applications
• It doesn’t conduct electricity makes it common for high-tech
applications, such as wires and cable.
• Also widely used in medical applications because it’s impermeable to
germs, easily disinfected and provides single-use applications that
reduce infections in healthcare
• Due to its versatile properties, such as lightweight, durable, low cost
and easy process ability, PVC is now replacing traditional building
materials like wood, metal, concrete, rubber, ceramics, etc. in several
applications.

PVC - Poly Vinyl Chloride

PVC – Types
PVC forms
Flexible or
Plasticized
Rigid or
Unplasticized
PVC types
CPVC
PVC-O
PVC-M
UPVC

PVC – Types
1. Plasticized or Flexible PVC: formed by the addition of compatible
plasticizers to PVC which lower the crystallinity. These plasticizers
act like lubricants resulting in a much clearer and flexible plastic.
This type of PVC is sometimes called as PVC-P.
2. Unplasticized or Rigid PVC: means no plasticizer, is a stiff and
cost-effective plastic with high resistance to impact, water, weather,
chemicals and corrosive environments. This type of PVC is also
known as UPVC, PVC-U or uPVC.
3. Chlorinated Polyvinyl Chloride or perchlorovinyl: prepared by
chlorination of PVC resin. High chlorine content imparts high
durability, chemical stability and flame retardancy. CPVC can
withstand a wider range of temperatures.
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PVC – Types
4. Molecular Oriented PVC or PVC-O: formed by reorganizing the amorphous
structure of PVC-U into a layered structured. PVC-O has enhanced physical
characteristics (stiffness, fatigue resistance, lightweight, etc.). Used for
pressure pipes for drinking water & also well suited for buried non-potable
applications such as irrigation and sewer pumping mains.
5. Modified PVC or PVC-M: It is an alloy of PVC formed by addition of
modifying agents, resulting in enhanced toughness and impact properties viz.
resistance to cracking. This enhanced toughness enables modified PVC
pipes to be manufactured with a thinner wall, with subsequent material
savings and improved hydraulic properties.
PEX - Cross-linked Polyethylene: A great choice for easy installation, freeze
resistance, and connecting to metal pipes, but it is more expensive than PVC and
not good for direct sunlight. PVC has a longer lifespan with great durability and
affordability but is not suitable for hot water.
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PVC – Properties
1. Electrical Properties: PVC is a good insulation material.
2. Durability: PVC is resistant to weathering, chemical rotting, corrosion, shock and
abrasion. It is therefore the preferred choice for many long-life and outdoor
products.
3. Flame Retardancy: PVC products are self- extinguishing.
4. Cost/Performance Ratio: PVC has good physical as well as mechanical
properties and provides excellent cost-performance advantages. It has long life
span and need low maintenance.
5. Mechanical Properties: PVC is abrasion-resistant, lightweight and tough.
6. Chemical Resistance: PVC is resistant to all inorganic chemicals. It has very
good resistance against diluted acids, diluted alkalis and aliphatic hydrocarbons.
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Polystyrene(PS)
• A naturally transparent thermoplastic made
from the monomer known as styrene.
• Available as both a typical solid plastic as
well in the form of a rigid foam material
• It is rigid, lightweight, versatile, insulates very
well and cheap.
• Available for food packaging and construction
industries.
• Examples: Cups, takeout food containers,
shipping and product packaging, egg cartons,
cutlery and building insulation.
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Polystyrene(PS)
• Used in making electrical Appliances, Automative
parts, food packaging material, medical devices,
components – as it is inert (doesn’t react with other
materials), cost-effective and long-lasting.
• Also used for Electronics - housing and other parts
for televisions, computers and all types of IT
equipment, where the combination of form, function
and aesthetics are essential.
• For Insulation - provides excellent thermal insulation
in numerous applications, such as building walls and
roofing, refrigerators and freezers, and industrial cold
storage facilities. Polystyrene insulation is inert,
durable and resistant to water damage.
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Polystyrene – Forms & Types
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PS
Solid
GPPS
HIPS
Foam PS or
Styrofoam
EPS
XPS
GPS
Film OPS

Polystyrene(PS) - Types
• General-purpose polystyrene is clear,
hard, and rather brittle. It is an
inexpensive resin per unit weight.
• Expanded polystyrene foam (EPS),
Extruded polystyrene foam (EXPS).
• High Impact Polystyrene
• OPS – Oriented Polystyrene film
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Acrylics
• A transparent plastic material with outstanding
strength, stiffness, and optical clarity.
• Also known as plexiglass, is a useful, clear
material that resembles glass, but offers better
transparency and weighs 50% less than glass of
equal thickness.
• Acrylic sheet is easy to fabricate, bonds well with
adhesives and solvents, and is easy to
thermoform.
• It has superior weathering properties compared to
many other transparent plastics.
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Acrylics
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Forms
Flat sheets
Elongated
tubes
Moulding
Powder
Types
Cast
Extruded

Acrylics
• Acrylic’s clarity, light weight, impact resistance, and weather
resistance, make this material a popular choice for architectural
applications. Acrylic sheet is used in everything from windows and
wall partitions to lighting fixtures and canopies.
• Available in clear as well as a wide variety of tints and colours. It
can also be mirrored or opaque.
• Acrylic also comes in different grades to suit different
manufacturing processes. These grades offer varying levels of
heat resistance, light transmissions, impact strength, flow rates
and release capabilities.
• Acrylic can also be coated to supplement characteristics such as
scratch resistance, anti-fogging, glare reduction and solar
reflectivity.
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Polycarbonate (PC)
• A naturally transparent amorphous thermoplastic.
• Has very good heat resistance and can be
combined with flame retardant materials without
significant material degradation.
• Useful for applications requiring transparency and
high impact resistance. It is a lighter alternative to
glass and a natural UV filter.
• It is a tough, transparent plastic material with
outstanding strength, stiffness, and impact
resistance. Polycarbonate’s optical clarity makes
it ideal for applications such as machine
guards, signs, architectural glazing, face shields,
skylights, and POP displays.
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Polycarbonate (PC) - Types
• Types of PC sheets-
• Clear Polycarbonate
• Abrasion-Resistant Polycarbonate
• Mirrored Polycarbonate
• Anti Static Polycarbonate
• Bulletproof Polycarbonate
• Coloured/Tinted Polycarbonate
• Flame Retardant Polycarbonate
• FDA-Approved Polycarbonate
• Multiwall Polycarbonate - can be used in
greenhouses, skylights, solariums, atriums and
more.
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Rubber – Polymeric Material
• Also known as elastomers
• Having the unique property of undergoing
large deformations under load and
returning to their original shape and
dimension on its removal owing to
lengthening and shortening of the springs
of polymeric chains.
• Elastomeric molecule is not straight
chained but is in the form of coil.
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Rubber
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Types
Natural
Made from the sap occurring in
cells of the various parts of the
plants known as latex.
Latex  diluted 
coagulated  treated 
Crude rubber
Crude rubber known as crepe
rubber and smoked rubber
which is further processed,
milled and vulcanized to
produce commercial rubber.
Synthetic
Mixture of natural rubber and
thermoplastic vinyl high
polymers.
e.g.- Styrene rubber, Silicon
rubber, Neoprene, Butyl rubber,
Polyurethane rubber
GPSR – freely used
E.g. - SBR,PBR, IR…etc.
SPSR – used for special end use
E.g. – EPDM, Butyl, Silicon,
Choloroprene, Nitrile…etc.

Rubber – Applications
• Most suitable material for conveyer belts, linings for
tanks, tyres, gaskets, mountings, hoses, insulating
coatings and toys.
• Phenolaldehyde resin with waste rubber is used to
make flooring tiles.
• Like cyclised rubber chlorinated rubber, is a modified
form of natural rubber, most widely used in the
production of protective coatings and adhesives.
• Rubber hydrochloride, on processing can produce thin
films of wrapping and packages.
• Rubber is also being used increasingly in the
manufacture of foam rubber, which is used in
upholstery and furniture.
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EPDM
• Ethylene propylene diene monomer
• A synthetic rubber
• A copolymer of ethylene, propylene and a
small amount of non-conjugated diene
monomers (3 – 9 percent)
• Available in form – liquid, solid rubber,
foam rubber, sponge rubber
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EPDM - Properties
• Have excellent heat, ozone/weathering, and aging
resistance.
• Also exhibit excellent electrical insulation,
compression set, and low temperature properties,
but only fair physical strength properties.
• Their resistance to chemicals is generally good.
• Probably the most water resistant rubbers
available but have poor flame resistance.
• Insulates and reduces noise
• Also very flexible
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EPDM - Applications
• In automotive industry - include radiator and
heater hoses, window and door seals, O-rings
and gaskets, accumulator bladders, wire and
cable connectors and insulators, and weather
stripping
• Major applications are roofing & waterproofing,
such as bitumen modifications, facade and
parapet sealants, expansion joints, & pool- and
tank liners.
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Neoprene
• A synthetic rubber, also called chloroprene
• A combination of carbon, hydrogen, and
chlorine polymers or created through the
polymerization of chlorine.
• Properties –
• Oil, alkali and acid resistant, but it’s susceptible to
aromatic and oxygenated solvents
• More resistant to corrosion and degradation than
many other rubbers.
• Also weather and fire-resistant, with thermal
insulating and waterproofing qualities.
• Durable, chemically stable & flexible over a wide
range of temperatures.
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Neoprene - Applications
• Suitable for use such as sports and medical
equipment, tech covers and sleeves, wetsuits,
and safety gloves - as well as for a variety of
outdoor applications—including use as hoses,
gaskets, seals, coatings, and linings.
• A common material in marine equipment and
diving suits, but it’s also used in rubber gloves
as a latex substitute, in roofing, and for
applications that require moderate chemical &
oil resistance.
• Neoprene is also commonly used in corrosion-
resistant coatings, high-pressure adhesives,
gaskets, and belts, vibration mounts, and
weather stripping.
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EPDM vs Neoprene
11/11/2022 75
# EPDM Neoprene
1
Good electric and noise resistance, steam
resistant and more ozone resistant.
Good thermal insulation and resistance to
chemicals, oils, and fire.
2 Both rubbers are good for general purpose applications, and can be extruded and molded.
3
They have fair to good tear resistance, better abrasion resistance, and excellent weathering
properties, with similar low temperature limits.
4
Functions better in higher temperatures,
with a maximum of 300-350 degrees F.
Handles only up to 225 degrees F.
5 Relatively cheaper Expensive
6 Less flame resistant More flame resistant

Bakelite – ‘material of a 1000 uses’
• First synthetic plastic
• A polymer made up of the monomers
phenol and formaldehyde.
• This phenol-formaldehyde resin is a
thermosetting polymer.
• Also chemically known as polyoxybenzyl
methylene glycol anhydride.
• A condensation polymer or a phenolic
resin.
• Paved the way to the 'Age of Plastics’.

Bakelite – ‘material of a 1000 uses’
• A heat-resistant, scratch-resistant & also
resistant to several destructive solvents
material.
• Can be quickly molded & has very smooth
molding.
• Resistant to electric current.
• Lightweight, durable and could be molded into
nearly infinite shapes.
• Usually brown/amber/black but can be made in
a variety of bright colors.

Bakelite
• Can be used in manufacturing electrical switches
and machine parts of electrical systems.
• Also been used for making the handles of a
variety of utensils and to make different parts of
many objects.
• Used in the manufacture of clocks, buttons,
washing machines, toys, kitchenware, and other
items.
• Earlier fashion jewelry were also made.
• Available in sheet, rod and tube form for various
applications under various commercial brand
names.
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Nylon
• Polyamide (PA) plastic
• A synthetic thermoplastic polymer
• Commonly used in injection molding applications.
• A versatile, durable, and flexible material often used
as a more affordable alternative to other materials
like silk, rubber, and latex.
• Material benefits include:
• High melting temperature
• Low friction
• High tensile strength
• Resistance to chemicals and abrasions
11/11/2022 79

Nylon
• It has low weight, high pressure-bearing capacity,
high wear and corrosion resistance, highly durable
and excellent impact resistance.
• Another advantage is Nylon’s low coefficient of
friction, which means that it can often be applied
with low or no lubrication.
• Most widely available in black, white, and its natural
color (off-white or beige).
• Exceptionally strong, relatively resistant to abrasion
and moisture absorptivity, long-lasting, resistant to
chemicals, elastic, and easy to wash material.

Nylon
• The most common variant for engineering
applications is Nylon 6/6 - can be extruded
(melted and forced through a die) and is also a
suitable plastic for both injection molding and
3D printing. It has a high melting temperature,
making it an excellent substitute for metals in
high-temperature environments (e.g., under the
hood of a vehicle).
• Common variants include Nylon 6, Nylon 6/6,
Nylon 66, and Nylon 6/66. The numbers
indicate the number of carbon atoms between
acid and amine groups.
11/11/2022 81

Nylon
• Used for a variety of applications, including
clothing, reinforcement in rubber material like car
tires, for use as a rope or thread, and for many
injection molded parts for vehicles and
mechanical equipment.
• Often used as a substitute for low-strength
metals.
• Nylon is often used in rods, sheets, tubes,
sheaves, wear pads, outrigger pads, drapery
hardware, roofing bolts, fixtures, plumbing fittings,
window frame spacers, and even safety nets.
11/11/2022 82

GFRP/ FRP/ GRP
• Glass Fibre Reinforced Plastic / Fibre glass Reinforced
Plastic/ Fiberglass
• A composite material – Glass fibres + resins
• Glass fibres provide stiffness & strength & resins
provides a matrix to transfer load to fibres.
• They may be randomly arranged, or conveniently
oriented.
• The polymer matrix is usually an epoxy, vinylester, or
polyester thermosetting resin.
• Additives are added to lend special properties to FRP.
11/11/2022 83

GFRP/ FRP/ GRP
• Plastic resins are strong in compressive loading; the
glass fibers are very strong in tension. By combining the
two materials, GRP becomes a material that resists both
compressive and tensile forces very well.
• Fiber reinforced plastics –
• Based on type of fibres - Wood (cellulose fibers), Carbon fiber
reinforced plastic or CRP, and Glass-fiber reinforced plastic or
GRP (informally, “fiberglass”).
• Based on matrix - Short fiber thermoplastics, long fiber
thermoplastics or long fiber reinforced thermoplastics, glass mat
thermoplastics, and continuous fiber reinforced thermoplastics &
Thermoset composites.
11/11/2022 84

GFRP- Classification
11/11/2022 85
GFRP
Glass
S-Glass
C-Glass
E-Glass
Other Glass
Resin
Polyester
Vinyl Ester
Epoxy
Polyurethane
Thermoplastic
Others
Manufacturing
Process
Filament winding
Layup
Others
End use
Transportation
Building &
Construction
Electrical &
Electronics
Renewable Energy
Infrastructure
Others

GFRP/ FRP/ GRP - Properties
1. Aesthetically appealing
2. Corrosion resistant
3. Dimensional stability
4. Durable
5. Easy to repair
6. Easily fabricated
7. Light transmission
8. Light weight – reduction in dead
load
9. Low maintenance – pigmented &
unaffected by changing weather
conditions.
10. Low investment in production &
finishing tools
11. High strength to weight ratio
and
12. Thermal resistance
11/11/2022 86

GFRP/ FRP/ GRP - Applications
1. As formwork for high quality
concrete shuttering
2. For unique shapes, wide
dimensions, lightweight domes
3. Door & window frames
4. Internal partitions & wall paneling
5. Roof sheets – translucent,
corrugated sheets
6. Structural sections – corrosion
resistant, choice of color, can be
machined, bolted, riveted &
tapped.
7. Temporary shelters – watchman
cabins, green houses, project site
shelters
8. Water storage tanks – superior to
steel, concrete or G.I. tanks
9. Rebars
10. Cladding material of bent into
wire frame structures.

Some other plastics -
PU – Polyurethane
PP – Polypropylene
Polyester
11/11/2022 89

Unit 2_Plastics.pdf

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