Energy

1. B.E. SEMESTER-I
ENGINEERING CHEMISTRY
UNIT (POLYMER)
Dr. R. M. KHARATE
DEPATMENT OF
APPLED SCIENCES AND HUMANITIES

2. CLASSIFICATION OF POLYMERS
POLYMERS
METHOD OF
PREPARATION
PHYSICAL
PROPERTIES
STRUCTURE
1. ADDITION
POLYMERIZATION
2. CONDENSATION
POLYMERIZATION
1.ELASTOMERS
2. THERMOPLASTICS
3. THERMOSETTING
1. LINEAR CHAIN POLYMER
2. HOMO POLYMER
3. CO-POLYMER
4. BRANCHED POLYMER
5. BLOCK POLYMER
6. GRAFT POLYMER

3. CLASSIFICATION OF POLYMERS ON THE BASIS OF STRUCTURE

4. INDIVIDUAL POLYMERS
POLYVINYL CHLORIDE (PVC)
CRACKING
V.P. 500
0
C
150
0
CAlCl3
52
0
C, 9 atm.
Peroxide

5. INDIVIDUAL POLYMERS
POLYVINYL CHLORIDE (PVC)
Properties :
1. It is colourless, odourless, tasteless, noninflatable powder.
2. It shows chemical resistance towards atmospheric oxygen, acids,
alkalies But it is soluble in hot chlorinated hydrocarbon like
ethylchloride
Unplastizied PVC is rigid in naure and therefore it Is used in acid
recovery plant, for making pipes,Sheets, as tank linging , light
fitting, safety helmets,Refrigerator components, toys etc
Plasticized PVC is prepared by adding plastisizer such as
dibutyl-phthalate to rigid PVC . It gives flexibility and water proof
Nature to plasticized PVC. Therefore it use for making
1. Kitchen appliences
2. Curtaining’s
3. Ladies handbags
4. Raincoats, table-cloth, shoes for beach were

6. INDIVIDUAL POLYMERS
POLYTETRAFLUROETHYLENE (PTFE)
Properties: Strong polymer (C-F bond) , high softening
point (330
0
C), shows resistance towards acids , alkalis
but gets attacked by hot alkali metals, high electrical
insulation properties, excellent toughness and heat
resistance.
Applications: Wire and cable insulation , Laminates for
printed circuitry , non lubricating bearings, packing volves,
gaskets, insulator for motors , generators and transformer

7. PHENOL-FORMALDEHYDE RESIN (BAKELITE)
It is a condensation product of phenol and formaldehyde. It
is prepared by reacting phenol with formaldehyde in
presence of acid or alkali to give mono, di, tri methylol
phenols. The product formed depends upon the following
factors.
1. Phenol to Formaldehyde ratio (P/F ratio)
2. The kind of catalyst used (acid or alkali)
3. Tempt and time of reaction

8. PHENOL-FORMALDEHYDE RESIN (BAKELITE)
Case-I. P/F > 1 Catalyst used is acid.
The methylol derivatives condenses with phenol to form dihydroxy
diphenyl methane. These on further condensation gives the low
molecular weight linear Bakelite(Novalac)
Further condensation

10. Properties of Bakelite:
1. It is hard , rigid and strong material
2. Excellent heat and moisture resistance
3. Good electrical insulation characteristics.
4. Dark pinkish brown colored .
5. Water , acids, salts resistant but affected by alkalis.
Applications of Bakelite:
1. Electrical appliances in the form of switches, plugs,
heater handles etc.
2. Telephone parts, radio , TV Cabinets, bearings.
3. Binding material for plywood.
4. In paints and varnishes.
5. In production of ion exchange resin(as H
+
Exchanger ).

11. RUBBERS OR ELASTOMERS
VALCANIZATION OR RECOMPOUNDING OR CURING OF RUBBER
Rubber is a polymer which when stretched elongest 4 to 10 times and as
soon as
stretching force is releases , it comes to its original position.
Types of rubber:
1 Natural rubber
2. Synthetic rubber
Natural rubber: It is a elastic polymer obtained naturally from the fluid
or emulsion of a rubber tree (Hevea Brasiliensis) . The natural rubber
contains number of isoprene units(monomers) so it is called as
polyisoprene .
2-methyl 1,3 butadiene
Isoprene Polyisoprene

12. RUBBERS OR ELASTOMERS
VALCANIZATION OR RECOMPOUNDING OR CURING OF RUBBER
Preparation:
The latex is obtained from the bark of rubber tree. Then following two
processes are carried on the latex.
1. Creping:
Latex +
water
Filter 1% Acetic
acid
Coagulated
white mass
Passes
through
creping
machine
(Roller)
Sheet
(creped
rubber)
Sheet
Pass through vapours
of tar oil for 4 days(at
40-50 oC)
Increases storage life of
rubber
2. Smoking
Drawbacks of natural rubber:
Brittle at low temperature , low tensile strength absorbs water,
attacked by non-polar solvents And oxiding agents, on oxidation in air
shows change in color , little durability, when stretched To great
extent deforms permanently , low electrical insulation character, high
elasticity , poor Chemical resistance

13. RUBBERS OR ELASTOMERS
VALCANIZATION OR RECOMPOUNDING OR CURING OF RUBBER
Vulcanization: To improve the properties of rubber Good Year in
1839 discovered a process known as vulcanization.
Rubber
5 % Sulphur Tough,
Frictionless
rubber
Accelerator
Thiourea
Increases
rate of
vulcanization
Activator
ZnO
Activate the
action of
accelerator
Antioxidants
Prevents
oxidation of
rubber
Fillers like carbon
black or silica
Coluring agents
Rubber
having
particular
color
110 – 140
0
C
TiO2
Lead
chromate
Chromium
oxide
Ferric
oxide

14. SYNTHETIC RUBBERS
STYRENE RUBBER (GR-S OR BUNA-S ORSBR OR BSR)
Preparation: It is prepared by
Addition Co-polymerization of two
monomers Butadiene(75%) and
styrene(25%) or in 3:1 ratio in
presence of Na as a catalyst
Properties:
1. Possesses high abrasion resistance
2. High load bearing capacity
3. Oxidizes readily
Applications:
1. Motor tyres, Gaskets
2. Shoe soles
3. Cable insulator

15. SYNTHETIC RUBBERS
NITRILE RUBBER (GR-A OR BUNA-N OR BUTADIENE-ACRILONITRILE RUBBER
Preparation:
It is prepared by Addition Co-polymerization of two monomers
Butadiene(75%) and Acrylonitrile (25%) or in 3:1 ratio in presence
of peroxide.
Properties:
1. Possesses good resistance towards heat, oils, acids but less
resistance towards alkalis.
2. It can be vulcanized 3. Good electrical insulation properties
Applications:
1. For making tank lingings
2. In manufacturing of aircraft components, printing rollers, automobile parts
3. As a oil repellent
1,3-Butadiene

16. SYNTHETIC RUBBERS
BUTYL RUBBER
BUTYL RUBBER
Preparation:
It is prepared by Addition Co-polymerization of two monomers
Isobutylene and Isoprene.
Properties:
1. Possesses good abrasion and heat resistance
2. Good resistance towards polar solvents but easily attacked by
hydrocarbons.
Applications:
1. For making cycle and automobile tubes, hoses, conveyer belts,
tank linings, insulation for high voltage wires etc.