Polymer are long chains of small molecules called monomers. There are different types of polymers including thermoplastics, thermosets, and natural polymers like rubber. The physical properties of polymers depend on factors like chain length, side groups, branching, and cross-linking. Rubber is a natural polymer made of isoprene monomers. It is elastic, flexible, resistant to chemicals and heat, and a good insulator. The main uses of rubber include tires, footwear, seals, bearings, and expansion joints in construction.

2. Polymer are long chain giant organic
molecules assembled from many small
molecules called monomers .
• More monomer molecules joined in units
of long polymer.
CLASSIFICATIONS OF POLYMERS
Thermoplastics
Thermosets
Long chain Polymers
Natural polymers
Homopolymer
Copolymer

3. Properties of Polymers
The physical properties of a polymer, such as its
strength and flexibility depend on:
• Chain length - in general, the longer the chains
the stronger the polymer;
• Side groups - polar side groups give stronger
attraction between polymer chains, making the
polymer stronger;
• Branching - straight, un branched chains can
pack together more closely than highly branched
chains, giving polymers that are more crystalline
and therefore stronger;
• Cross-linking - if polymer chains are linked
together extensively by covalent bonds, the polymer
is harder and more difficult to melt.

4. Characteristics of Polymers
Low Density.
Low coefficient of friction.
Good corrosion resistance.
Good mould ability.
Excellent surface finish can be obtained.
Can be produced with close dimensional
tolerances.
Economical.
Poor tensile strength.
Low mechanical properties.
Poor temperature resistance.
Can be produced transparent or in different
colours

6. Rubber is a natural polymer of
Isoprene (usually cis- 1,4-
polyisoprene)
Rubber is also known as an
elastomer.
It can be defined as a sticky,
elastic solid
Natural rubber - Produced from a
milky liquid known as latex
Synthetic rubber- Produced
artificially.

7. Types of Rubber
 Natural Rubber
 Latex
Coagulated by weak acetic acid after removing
the impurities.
It is then passed through rollers to get creep
rubber.
It is then processed to get commercial rubber
compounds.
 Synthetic Rubber
 General purpose synthetic rubber
Stryene Butadiene Rubber (SBR)
 Special purpose synthetic rubber
Have special qualities to suit different purposes
Neoprene

8. Characteristics of rubber
Flexible, Elastic
Not transparent
Water proof/repellence
Hard, Strong
Insulate electricity
Acid & alkaline resistant
Doesn’t conduct to heat

9. Properties
 Physical Properties
Non reactive
Chemically Resistant to many fluids
including many water, weak acids & alkalis
Non conductive
Poor conductor of heat & electric
Elastic
Tough
Electric resistant
Electric insulator

10.  Chemical Properties
Polymers
Consists of isoprene molecules fitted
together in loosed chains
Consisting long chains of one or more
type of molecules
Contain long chains of hydrogen and
carbon molecules
Rubber go through vulcanization
through adding sulfur which result in a hard,
durable material with great mechanical
properties.

11. Functions
Sustainability
Rubber has many uses that makes
rubber & recycled rubber products a valuable
sustainable material.
Rubber is being used as repairing
material in United States Pave roads & bridge
Surface of roads are upgraded with
ground rubber material
Playgrounds with rubber flooring Not
only safer but its own aesthetic value
Used & re-purposed for protective gear
Create fibers for clothing & outerwear
Lower the budget in construction

12.  Green Materials/ Eco Friendly Materials
Rubber is produced naturally which is a definite
green material as rubber recycling has become more
common.
There is market demand which keeps vast amounts
of rubber out of landfills
Importance of Recycled Rubber
Reclaiming & recycling rubber uses less energy
than producing a new rubber.
Recycling rubber reduces the demand for new
natural rubber which may keep rubber tree plantations
from expanding into sensitive tropical ecosystems.
Keeping rubber out of landfills protects
environments as well as human health
• Tire fires in landfills will cause pollution &
pose a significant safety hazard.

13.  AestheticValue
Can be obtained in different types of
color
Have great eye appeal
Easily shaped, hence allow designer to
create seamless installations More safety
Comfortable
Hygienic
Can also be engineered with
antimicrobial properties

14.  Durability
 Vulcanization
Forming cross-link between polymer chains
Less sticky, more durable
(Vulcanized rubber)
• Tires, shoe soles, hoses, conveyer belts
& hockey pucks
(Hard vulcanized rubber)
• Bowling balls, saxophone mouth pieces
Can be called ebonite & vulcanite
Nature of the rubber
Can be compressed & stressed
NON reactive to acid & alkaline
Heat & electrical insulator

17. Application
 Rubber flooring
Used to a large extent in public and
industrial buildings because of their good
wearing qualities, resiliency (i.e., elasticity)
and noise insulation.
Made up of pure rubber mixed with
fillers, such as cotton fibre, granulated cork
or asbestos fibre and the desired colouring
pigments.
Manufactured in the form of sheets
or tiles, in a variety of patterns and
colours.

19.  Rubber Adhesive
Most all rubber-based glues and bonding
agents are made of rubber mixed with other
compounds.
Suited as a bonding element because of its
flexibility.
Some types of bonding compounds made with
rubber are used as sealants.
However rubber adhesive is extremely
flammable.
• It is not suitable for bonding in high temperature
situations
• It is generally used where dampness is an issue
because of its water resistance.
• might be damaged by other solvents, such as oil and
grease, and not suitable for bonding heavy pieces.

21. Bearings pad
Used extensively in standard
construction applications, buildings &
structural steel bearings applications.
Synthetic fibres are added to the
base rubber compounds to create an internal
stiffening like steel reinforced concrete.

22. Rubber bearing pads has been used
in:
• Bridge bearing masonry pads
• Handrail bearing pads
• Pads between steel beams, girders,
grates & columns
• Pads between bridge and roof beams
and substructures
• Shock and vibration isolation
• Heavy equipment mounting pads
• Railway tie pad applications
• Pads underneath concrete vaults

24. Expansion joints
A mid-structure separation which designed
to relieve stress on building materials caused by
building movement by:
• Thermal expansion & contraction caused by
temperature changes,
• Sway caused by wind,
• Seismic events
It marks a gap through all building
assemblies including walls, floors, decks, planters &
plazas, etc. because the joint bisects the entire
structure.
Used to bridge the gap & restore the
building assembly functions while being able to
accommodate the expected movements.

26. Both natural & synthetic rubber
is not widely use in the construction
industry.
However, it is mainly used in
household & industrial products
Therefore, rubber industry have
a bright future for rubber industry.

27. RUBBER
PROCESSING AND
PRODUCTS

28. • Many of the production methods used for
plastics are also applicable to rubbers
• However, rubber processing technology is
different in certain respects, and the
rubber industry is largely separate from the
plastics industry
• The rubber industry and goods made of
rubber are dominated by one product: tires
− Tires are used in large numbers on
automobiles, trucks, aircraft, and bicycles

29. Rubber Processing and Shaping
• Production of rubber goods consists of
two basic steps:
1. Production of the rubber itself
Natural rubber is an agricultural crop
Synthetic rubbers are made from
petroleum
2. Processing into finished goods, consisting
of:
(a) Compounding
(b) Mixing
(c) Shaping
(d) Vulcanizing

30. Compounding
• Rubber is always compounded with additives
− Compounding adds chemicals for
vulcanization, such as sulfur
− Additives include fillers which act
either to enhance the rubbers mechanical
properties (reinforcing fillers) or to extend
the rubber to reduce cost (non reinforcing
fillers)
− It is through compounding that the
specific rubber is designed to satisfy a given
application in terms of properties, cost, and
process ability

31. Mixing
• The additives must be thoroughly mixed
with the base rubber to achieve uniform
dispersion of ingredients
• Uncured rubbers have high viscosity so
mechanical working of the rubber can
increase its temperature up to 150°C
(300°F)
• If vulcanizing agents were present from
the start of mixing, premature vulcanization
would result the “rubber processors
nightmare”

32. Shaping and Related Processes
• Shaping processes for rubber products can
be divided into four basic categories:
1. Extrusion
2. Calendering
3. Coating
4. Molding and casting
• Some products require several basic
processes plus assembly work
− Example: tires

33. Vulcanization
• The treatment that accomplishes cross linking of
elastomer molecules, so that the rubber becomes
stiffer and stronger but retains extensibility
• On a submicroscopic scale, the long chain
molecules of rubber become joined at certain tie
points, the effect of which is to reduce the
ability of the elastomer to flow
− A typical soft rubber has 1 or 2 cross
links per 1000 units (mers)
− As the number of cross links increases, the
polymer becomes stiffer and behaves more and
more like a thermosetting plastic (hard rubber)

34. The Rubber Industries
• Production of raw NR might be classified as
an agricultural industry because latex, the
starting ingredient, is grown on plantations in
tropical climates
• By contrast, synthetic rubbers are produced
by the petrochemical industry
• Finally, processing into tires and other
products occurs at processor (fabricator)
plants, commonly known as the rubber industry
− The company names include Goodyear,
B. F. Goodrich, and Michelin, all reflecting the
importance of the tire

35. Production of Natural Rubber
• Natural rubber is tapped from rubber trees
(Hevea brasiliensis) as latex
− The trees are grown on plantations in
Southeast Asia and other parts of the world
• Latex is a colloidal dispersion of solid
particles of the polymer polyisoprene in water
− Polyisoprene (C5H8)n is the chemical
substance that comprises rubber, and its
content in the emulsion is about 30%
• The latex is collected in large tanks, thus
blending the yield of many trees together

36. Synthetic Rubber
• Most synthetic rubbers are produced from
petroleum by the same polymerization
techniques used to synthesize other
polymers
• Unlike thermoplastic and thermosetting
polymers, which are normally supplied to the
fabricator as pellets or liquid resins,
synthetic rubbers are supplied to rubber
processors in the form of large bales
− The rubber industry has a long
tradition of handling NR in these unit loads

37. Tires and Other Rubber Products
• Tires are the principal product of the
rubber industry
− Tires are about 75% of total rubber
tonnage
• Other important products:
− Footwear
− Seals
− Shock absorbing parts
− Conveyor belts
− Hose
− Foamed rubber products
− Sports equipment