TOPIC - RUBBER
CONSTRUCTION AND MATERIALS
BY:
KUSHAGRA GOEL
MOHD. KADIR

Rubber
 Rubber also known as elastomers are high polymers having a unique property
of undergoing large deformation under load and returning to their original
shape and dimension on its removal owing to lengthening and shortening of
the springs of spring polymeric chains (elastomer molecule is not a straight
chained but in form of coil )
 The upstretched rubber molecule is amorphous in stretching the molecules in
it get partially aligned to one another . On releasing the stress chain regains
its original coiled state

Rubber
 Rubber is very important engineering material for any nation the most one
being tire industry.
 India is the fifth largest natural rubber producing country in the world after
Malaysia, Indonesia, Thailand and Sri Lanka.
 Kerala State accounts for about 91 % of the total area under rubber industry
and for Kanyakumari district in Tamil Nadu, the percentage is about 5 % .
 The remaining 4% area is located in karnatka , Andman and Nicobar island,
Goa , Maharashtra and north eastern states.
 The total area under rubber cultivation in the country is about 522000
hectares.
 The commercial use of rubber came into existence with the discovery of
process known as the vulcanization in year 1836 by Good Year.

CHARACTERISTICS OF RUBBER
 FLEXIBLE
 ELASTIC
 NON TRANSPARENT
 HARD AND STRONG
 INSULATE ELECTRICITY
 ACID & ALKALINE RESISTANT
 DOESN’T CONDUCT

PROPERTIES
 PHYSICAL PROPERTIES
• NON REACTIVE
• CHEMICALLY RESISTANT TO MANY FLUIDS
• NON CONDUCTIVE
• POOR CONDUCTION OF HEAT AND ELECTRICITY
• ELASTIC
• TOUGH
• ELECTRIC RESISTANT AND INSULATOR

Classification
 NATURAL RUBBER
 SYNTHETIC RUBBER

NATURAL RUBBER
 Consists of basic material latex , dispersion of isoprene which polymerizes to
form long coiled chain of polyisoprene . It’s made from sap occurring in cells
of various parts of plants such as HAVEA BRASILIANSIS & GAUYILE .
 Latex is obtained by making incisions in bark of rubber tree allowing sap to
flow out . It’s collected and diluted to contain 15-20% of rubber and then
stained to remove any dirt . Thereafter rubber is coagulated by adding acetic
or formic acid . The coagulated rubber is then treated to produce crude
rubber known as CREPE RUBBER &SMOKED RUBBER which is further processed
,milled and vulcanized to produce commercial rubber .

Natural Rubber
 Plantation :
 The rubber trees are planted. They start oozing outafter a period of about 5 to 7 years and
continue to ooze out for a life to about 30 yrs.
 Anormal rubbertree gives about 10N to 50N of dry rubber per year.
 Tapping Latex :
 A vertical groove about 600mm long is made in the rubber tree by means of a pointed
knife at a height of about 1m from the ground level .
 The vertical groove is connected of slanting grooves inclined upward.
 An earthenware pot is attached at the lower end of vertical groove to collect the latex that
oozes out of the tree.
 The latex from the pot is taken by the tapper everyday or every alternate day and at the
time ,the grooves are slightly widened. The care should taken to see that the grooves do
not penetrate beyond the cambium layer of the tree.

Natural Rubber
 Purification:
 The impurities such as leaves ,sand,debris,etc.are removed.
 Coagulation :
 The latex then converted into a massive form by the process of coagulation.
 The coagulant usually adopted is weak acetic acid.
 The addition of coagulant converts latex into curd like form.
 It is then pass through rollers.
 The water from latex thus separated out and the natural rubber is obtained in the form
of Globules of sheets.

Natural Rubber
 The process of obtaining Natural Rubber is carried out in following
four stages.
 1) plantation
 2) Tapping Latex
 3) Purification
 4) Coagulation.

NATURAL RUBBER
CREPE RUBBER
 Produced by coagulating rubber in
presence of retarder like sodium
bisulphate .
 Then passed between rollers of
creping machine where most of
serum is squeezed out and a sheet
of resembling crepe is formed
SMOKED RUBBER
 Produced by pouring diluted latex
into tanks having sides with
vertical grooves .Diluted formic or
acetic acid is added and stirred .
 Partition plates are inserted and
left for 16 hours . Slabs formed are
removed and passed through series
of rollers with decreasing
clearance . The sheet are kept for
4 days in smoke house having a
temperature of 40-50%

Synthetic Rubber
 The term synthetic or artificial rubber was conceived through research and
development as a polymer which could be used to replace the natural rubber.
 The real beginning of a synthetic rubber industry started in USA , Germany and other
foreign countries.

Synthetic Rubber
The synthetic rubber can be grouped in the following two categories:
1) General purpose synthetic rubber:
 These rubbers are used freely in wide ranging applications.
 The most important all purpose rubber was then and still is a Styrene-butadiene
rubber . It was called earlier inn USA and Canada as GR-S and in Germany BUNA-S.
 It is now referred as SBR all over the world.
2) Special purpose synthetic rubber
 These rubbers are developed with especial end use in view and They include butyl
,nitrile ,chloroprene ,E.D.P.M. ,Acrylic , Polysulphide , silicone ,Viton etc.
 India is accounted for 0.5% of the total world production of synthetic rubber .
 First synthetic rubber plants of India , Synthetics and chemical ltd. Was setup at
Bareilly ,U.P. in 1961.

TYPES OF SYNTHETIC RUBBER
STYRENE BUTADIENE (SBR)
 Originally developed as a low cost
substitute for natural rubber
 Good water resistance and abrasion
resistance
 Poor weathering resistance, but can
overcome with specific raw materials
 Not recommended for contact with
oils and solvents
 Not used with concentrated acids or
alkalis
 Maximum continuous operating
temperature is about 225°F
BUTYL
 Very good resistance to most gases
including air
 highly resistant to ozone and
weathering
 Abrasion resistance close to
natural rubber and good for
concentrated acids and alkalis
 Not recommended for petroleum
product exposure
 Maximum continuous operating
temperature is about 300°F

TYPES OF SYNTHETIC RUBBER
EPDM
 Exceptional resistance to
weathering and ozone
 Excellent resistance to water, most
gases, steam, and heat aging
 Good for exposure to concentrated
acids and alkalis, but not
recommended for exposure to oils
and solvents
 Maximum continuous operating
temperature is about 350°F
FKM(VITON)
 High cost, but high performance
material
 Outstanding resistance to most
chemicals, oils and solvents
 Good oxidation and ozone
resistance
 Maximum continuous operating
temperature is about 650°F
 "Viton" is a trademark of DuPont
and signifies material produced by
DuPont

TYPES OF SYNTHETIC RUBBER
NITRILE (BUNA)
 Much better oil and solvent resistance
compared to either natural rubber or
Neoprene
 Recommended for most oil field
applications
 Can be formulated for use at low
temperatures
 Good compression set and abrasion
resistance, but poor weathering
resistance
 Can be used with concentrated acids
and alkalis but there are better
alternatives
 Maximum continuous operating
temperature is about 275°F
NEOPRENE (CHLOROPRENE)
 Good general purpose rubber with
properties close to natural rubber,
but is synthetically produced
 Better resistance to oils and solvents
compared to natural rubber but
similar low compression set
 Can be compounded for flame
resistance
 Good weathering resistance
 Poorer low temperature performance
compared to natural rubber
 Maximum continuous operating
temperature is about 275°F

APPLICATIONS

RUBBER FLOORING
 Used To A Large Extent In Public And Industrial Building Because Of Their Good
Wearing Qualities ,Resiliency And Noise Insulations .
 Made Up Of Pure Rubber Mixed With Fillers, Such As Cotton Fiber ,granulated
Color Asbestos Fiber And Desired Coloring Pigments
 Manufactured In Form Of Sheet Or Tiles, In A Varity Of Patterns And Colors

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.
 Not Suitable For Bonding In High Temperature Situations.
 Since Its Water Resistant It Is Used Where Dampness Is An Issue .
 Might Be Damaged By Some Solvents and not suitable for bonding heavy
pieces .

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 changed,
 Sway caused by winds,
 Seismic events
 It marks a gap through all building assemblies including walls , floors, deck,
planters , plazas etc. because the joint biscuits the entire section .
 Used to bridge the gap and restore the building assembly functions while
being able to accommodate the expected movements .

BEARING PADS
RUBBER BEARING PADS ARE USED IN :
 Bridge bearing masonry pads
 Handrail bearings pads
 Pads between steel beam , girders ,grates &columns
 Shock and vibration isolation
 Heavy equipment mounting pads
 Railway tie pad applications
 Pads underneath concrete vaults

THANK YOU