plastic

CONTENTS
 Introduction
 What is plastic?
 Types of plastics
 Applications
 It’s properties
 Manufacturing process
 The plastic identification code.
 Interesting facts

Introduction
Origination of plastics
• Plastic was discovered by famous
German chemist Christian Schonbein in 1846.
• Plastics were actually discovered accidentally.
Christian was experimenting in his kitchen and
by accident he spilt a mixture of nitric acid and
sulphuric acid. To mop that solution nitric and he
took a cloth and after moping he kept it over the
stove. After sometime, the cloth disappeared and
from there plastic got its name.

 Greek word ‘Plastikos’ To Mould
 Plastic is defined as polymers of long carbon chains .
 Carbon atoms are linked in chains and are produced in
long molecules.
 Fossil fuels have compounds containing hydrogen and
carbon (hydrocarbon) which act as building blocks for
long polymer molecules .
 These building blocks are known as monomers, they
link together to form long carbon chains called
polymers

What is plastic?
 A synthetic material made from a wide
range of organic polymers such as
polyethylene, PVC, nylon, etc., that can
be molded into shape while soft, and
then set into a rigid or slightly elastic
form
 Made by monomers.

Structure of Plastics.
Cross-Linked Networked
linear Branched
structure
Isomeric states
Geometrical isomer Stereoisomer
Cis Trans

Classification of plastics
 Generally synthetic polymers are divided into
three types on the basis of industry
Physical Classification
Commercial Classification
Functional Classification
Chemical Classification
1.Plastics
2.Synthetic fibers
3.synthetic
rubber

Physical Classification
1.Formed
2.Filled
3.Film
4.Foam
5.Fiber
6.Fines

1.Formed:
 It Includes rods, Casting, extrusions,
and molding.
 Covers structure in which there is a
significant thickness and mass of polymer
FUNCTION: heat transfer to and heat
absorption by adjacent material
surface area
volume
Is Low

 2.Filled:
 It includes reinforced plastics
 cover structures in which solid
material other than polymer are more
uniformly distributed throught the
material
FUNCTION: Heat transfer to and Heat
(polymer and also for filler)

 3.Film:
 It includes films,sheeting,coating,and
adhesives,covers.
 These structures thickness is very small relative to
length and width(<0.01inch)
 FUNCTION:heat transfer to and heat absorption
by adjacent material
one side otherside
Adhesives solids solids
coatings solids gas,liguid,solid
self-supportingsheeting gas,liquid,solid gas,liguid,solid

4.Foam:
 It includes cellular plastics ,structural
foam ,and honeycomb structures
 Covers structures in which gaseous
material are more or less uniformly
distrubuted throughout the polymer
 FUNCTION:heat transfer to and heat
 Low thermal conductivity

 5.Fiber:
 It includes fibers,filaments,fabrics,
and textiles.
 Cover structures in which the polymer
is present in the form of continuous
cylindrical rods(small diameter)
 FUNCTION:heat transfer to and heat

 6.Fines:
 Includes powders and dusts
 Cover materials which are finely divide
into small particles
 These are characterized by high surface
area per unit volume or unit mass
 Under certain conditions it can produce
dust explosions.

Venture
plastics
Speciality
plastics
Tonnage
plastics
Commercial
classification

 1.Tonnage plastics:
characterized: High demand and High volume,
High capital intensity, Relatively low R&D costs
Cost: < $1.00 per 1Lb
Small product differentation
Great need for vertical integration in raw materials
Examples : LDPE
HDPE
Polyvinyl chloride(PVC)
Polypropylene
Polystyrene

 2.Speciality plastics:
 characterized: low volume,lower capitial
intensity,moderately higher R&D costs
 Greater need for knowledge of end-use
applications
 Less need for raw materials base.
 Greater product differentiation
 Cost:$1.00-$4.00 and greater per
lb(0.4536Kg)

 3.Venture plastics:
characterized:low demand but promising
potential ,low volume but relatively high
sales revenues,low capital intensity,high
R&D costs
Need for knowledge of end use applications.
Definite product differentiation.
Cost:$3.0 - $30.0 and more per lb.

 These are often but not always similar to
commercial classification
 Tonnage plastics commodity plastics
 Specialty plastics engineering plastics
 Venture plastics high-performance
plastics
These classification is not always identical
 Thermoplastic polymers are tonnage plastics
 But part of thermoplastic polymers are in the form
of engineering grades.
 Polypropylene,polystyrene,ABS tonnage
plastics
 Upgraded (Polypropylene,polystyrene,ABS)
engineering plastics
 ABS Acrylonitrile-butadiene-styrene

1.Commodity plastics:
 Used in high volume
 Low Mechanical properties
 Low cost
applications:
(film packaging, photographic, magnetic tape,
clothing etc….)and variety of house hold products .
 Products:
 plates,cups,carrying Trays,medical
Trays,containers,seeding Trays,printed material,other
disposible items
 Examples: polyethylene,
polypropylene, polystyrene, polyvinyl
chloride, poly(methyl methacrylate and more

2.engineering plastics
 Better mechanical and/or thermal properties than
commodity plastics
 More expansive
 Produced in lower quantities and tend to be used for smaller
objects
 (low volume applications like mechanical parts)
 Example:
 Acrylonitrile Butadiene Btyrene (ABS), used for car
bumpers.
 polycarbonates, used in motorcycle helmets.
 polyamides (nylons), used for ski boots.

3. High-performance plastics:
 Amorphous and semi-crystalline polymers
 Amorphous polymer:
 Polysulfone (PSU), poly(ethersulfone) (PES) and
polyetherimide (PEI)
 semi-crystalline polymers:
 poly(phenylene sulfide) (PPS), polyetheretherketone (PEEK)
and polyether ketones (PEK)
 More expansive ( $ 100 (PEEK) per kilo)
 3 to 20 times as expensive as engineering plastics.
 Used in smaller amount
Characteristics:
1.Temperature stability is more than other standard
plastics
2.Temperature and mechanical features improved and
increased by increase degree of polymerization
3. Through substitution of aliphatic by aromatic units.

Example:
An even higher service temperature can be reached by linking
of aromatics with oxygen in PEEK

Chemical classification
Thermosetting
Thermoplastic

1.Thermoplastic plastics
A material that cures reversibly and softens when
heated above the glass transition temperature or
melting point, as well as becomes hard after
cooling is called a thermoplastic
 The long polymer molecules are joined to one
another by very weak bonds
 Linear polymers and combination of linear and
cross linked polymers come under thermoplastics.
 Two types
 1.High temperature thermoplastis
 2.engineering plastics.

Properties :
High strength and toughness
Better hardness
Chemical resistance
Durability
Self lubrication
Transparency
Water proofing

Types of Thermoplastics
 Acrylonitrile Butadiene Styrene(ABS)
 Acrylics
 Polyethylene
 Polypropylenes
 Polycarbonates
 Polystyrenes
 Polyetheretherketone(PEEK)
 Polyvinyl chloride(PVC)
 Polyphenyline sulphide
 Flurocarbons
 Polyamides

Applications:
 Polypropylene:
 reusable plastic food containers
 insulation for electrical cables
 ropes, carpets.
 Although relatively inert, it is vulnerable to ultraviolet radiation
and can degrade considerably in direct sunlight
 Polyethylene:
 LDPE:retail store bags , handling boxes of durable goods,
 MDPE: packaging film, gas pipes and fittings.
 HDPE:liquid laundry detergent bottles, water drainage pipes.
 UHDPE:manufacture moving machine parts, bearings, gears,bulletproof
vests.
 Polystyrenes:
 CD and DVD cases, plastic models of cars and boats,
insulation and packaging materials

 PVC
 Toys and credit cards,
 Resistant to acids and bases.
 Gutters and roofing sheets
 Pipes, electrical insulation, coats, jackets .
 Polycarbonate:
 hard plastic windows,
 car headlamps,
 electronic components,
 construction materials,
 data storage devices,
 automotive and aircraft parts,

 Nylon
 used in everything from swimming shorts to toothbrushes
 and umbrellas.
 parachutes
 women's clothing
 ABS:
 consumer products such as toys, appliances, and
telephones.
 Acrylic:
 motorcycle helmet, aircraft windows, viewing ports of
 submersibles, and lenses of exterior lights of automobiles
 eye lenses.

Thermosetting plastics
 Plastics that cannot be softened again by heating once they
are molded.
 usually made from much much bigger polymer chains
 Heavily cross-linked polymers come under the category of
thermosetting plastics.
 Example: Bakelite, melamine, PTFE,etc….
 Bakelite is used for making electrical switches
 melamine is used for floor tiles.
 polyurethane (insulating material in buildings),
 PTFE (nonstick coatings on cooking pots and pans),
 melamine (hard plastic crockery),
 epoxy resin (a tough plastic used
in strong adhesives and wood fillers).

Types of Thermosets
 Alkydes
 Allylies
 Amine
 Bakelite
 Epoxies
 Phenolic
 Polyester
 Silicone
 Polyurethane
 Vinyl Ester

 Bakelite:
 electrical insulators,
 plasticware
 Epoxys:
 casting
 adhesives
 protective coatings
 sealing and joining
 printed circuit boards(epoxy novolac resin)
 Vinyl Ester:
 molding and fast setting industrial protection
 To repair materials
EXAMPLES

 Polyester:
 sheet molding compounds
 bulk molding compounds
 filament winding
 protective coatings
 Polyurethane:
 coatings(water proofing)
 adhesives
 car parts
 shoe soles
 flooring
 synthetic fibers


Manufacturing process
It classified based on type of raw material used
type of end product that we want to make
Processing techniques for polymers
casting compression molding
extrusion Blow molding
Thermoforming rotating molding
Injection molding Transfer molding

Processing technique for Thermoplastics
 It is processed by heating up to glass
transition and formed into desired shape
with the application of pressure
Example : Extrusion , Thermoforming ,
Compression molding , Blow molding……

Processing technique for Thermosets
 Thermosets can be processed in two
steps
 First: Melted
 Second: poured into mold
 Mostly thermosets are in gel form so we
can change its viscosity
 Examples:Casting,Transfer
Molding,Injection molding…..

1.Casting
A liquid material is usually poured into a mold, which
contains a hollow cavity of the desired shape, and then
allowed to solidify. The solidified part is also known as
a casting
Used material:
Thermoplastic: Nylons,Acrylics
Thermosets: Polyesters,epoxys,Urethanes,Phenolics

Advantages Disadvantages
Low initial cost investment There is more labor intensive than
transfer molding
Flexible parts can be made Complex parts can’t be made
High production rate
Applications:
Applications
Household, items,
Designer toys,
sheets,
Wheels....

2.Thermoforming
 Thermoforming is a plastic processing technique in
which the thermoplastic sheets are formed with the
application of heat and pressure in a mold.
 Types of process
 Vacuum forming
 Pressure forming
 Matched die forming(mechanical )
Limitatons:
 Used for thin sheets only
 Heat is applied
 Pressure is applied
 Mold is used to deform the sheet into the desired shape

Vacuum Forming
The vacuum pressure is used to form the heated thermoplastic
sheet into desired shape
Thermoplastic sheet is placed on the mold surface and fixed
with the help of clamping unit
The sheet is heated until its softens and there after vacuum need
to applied quickly

Pressure Forming
The pressure that we applied in this pressure forming
method is more compared to the vacuum forming method.
The high pressure is developed in between the softened
sheet and pressure box
In a fraction of second the preheated sheet deform into
mold cavity

Matched Die Forming
 Also called Mechanical forming
 Contains two parts :1.Die
 2.Punch(core plug)

Advantages Disadvantages
Design Flexibility Poor surface finish
Low initial cost setup All parts need to be trimmed
Low production cost Parts may have non-uniform wall
thickness
Less thermal stress Very thick sheets can’t used
Good dimensional stability Limited materials can be used
Applications
Food packaging
Trays
Automotive parts
Building products
Material used
LDPE , HDPE
PS-Polystyrene,
PP-Polypropylene
PS-Polystyrene
PVC,ABS(Acrylonitrile )

3.Extrusion
 It is high volume manufacturing process
 Here the plastic material is heated to get
melted and extrude through die into desired
shape
 A cylindrical rotating screw is placed inside
the barrel which forces out molten plastic
material through die
 Cooling is basic step in extrusion.
 The plastic material is in the form of pellets or
granules
 Additives such as colorants and ultraviolet
inhibitors can be mixed in hopper

Types:
 Sheet/film Extrusion
 Blow film Extrusion
 Tubing Extrusion
 Co-Extrusion
 Compound Extrusion
 Extrusion coating
 Over jaketing Extrusion

Applications:
 Rods,
 Plates and Tubes
 Wires and cable coating ,
 hose liner,
 filaments,
 sheets,multilayer film,
 medical packings ,food packings etc…

4.Injection Molding
 It is one of the most commonly used
processing techniques for plastic
components
 Used for thin walled plastic parts for a
wide variety of shapes and sizes
 The plastic material is melted in the
heating chamber and then injected into
mold ,where it cools and finally the
finished plastic part is ejected
 This process is very rapid (2 to 60 seconds)

Types
Hand injection molding
Plunger type injection molding
Reciprocating screw type injection molding
Stages
Clamping
Injection
Cooling
ejection
Material used
Acetal, Acryline,
Nylon,
Polycarbonate,
PEEKPolyethane,
Polypropyline, PVC ……

Advantages:
Higher production rate
Minimum wastage of
material,
Complex geometry can easily
produced
Limitations:
Tooling cost high
High setup cost
Large undercuts cant be
formed
Applications:
Buckets
Toothbrushes
Small toys
Medical devices
Automobile components

5.Blow molding
 Blow molding is a manufacturing process that is used to
produce hollow plastic parts.
 By inflating a heated plastic until it conforms to the mold
shape and form the desired product
 Types:
 1.Extrusion blow molding
 2.Injection blow molding
Material used
HDPE
LDPE
Polypropylene
Polycarbonate
Polyethylene Terephtalate, PVC ……

The Plastic Identification Code

Interesting facts
 Its take 450 years for plastic to begin
decomposing
 In a year more than one plastic bag is made per
minute(600 billion)
 24 million gallons of oil are needed to
manufacture one billion plastic bottles
 A plastic cup can take 50-80 years to decompose
 11% of household waste is plastic in that 40% Is
plastic bottles.

An example of the 1940s to 1950s concept of plastics in
buildings from The House That Plastics Built

Reference
 https://byjus.com/chemistry/plastics/
 http://www.explainthatstuff.com/plastics.ht
ml
 http://nptel.ac.in/courses/112107086/13
 https://www.online-sciences.com/industries
 https://www.thoughtco.com/high-
temperature-thermoplastics-820349

Presented
by
M. RavindraSSK
Civil engineering
2 nd year
Veltechuniversity
Avadi-Chennai

plastic

More Related Content

What's hot

What's hot (20)

Similar to plastic

Similar to plastic (20)

Recently uploaded

Recently uploaded (20)

plastic