Plastic is a synthetic material made from organic polymers that can be molded while soft and set into a rigid form. It is classified based on its behavior with heat (thermoplastics soften with heat, thermosetting plastics harden permanently), structure (homogeneous or heterogeneous), and properties (rigid, semi-rigid, soft, elastic). Common thermoplastics include polyethylene, PVC, and nylon, while epoxies, phenolics, and polyesters are thermosetting plastics. Plastics are composed of polymers, carbon, oxygen, and other elements, and may include additives like fillers, pigments, plasticizers, and catalysts to modify their properties.

2. plastic
Plastic is a synthetic material made from a wide range of
organic polymers such as polyethylene, PVC, nylon, etc., that
can be moulded into shape while soft, and then set into a
rigid or slightly elastic form.

3. Composition of plastic
Organic
Polymers + Carbon + O2 +
Nitrogen Sulphur+
Organic Polymers may include :
CHA LK, STA RCH, IVORY DUST, WOOD F LOO R , ZINC
OX IDE

4. Classification of plastic
There are many ways of classifying plastics. They can be
classified considering various aspects, as according to their:
1. Behaviour with respect to heating,
2. Structure, and
3. Physical and mechanical properties.

5. Classification of plastic
Behaviour with
respect to heating Structure Physical and
mechanical properties
Thermo-plastics
Thermo-setting
Homogeneous
Heterogeneous
Rigid Plastics
Semi-rigid
Plastics
Soft Plastics
Elastomers

6. Themoplastic & thermosetting
Basic difference between Thermoplastics and Thermosetting plastics
THERMOPLASTICS
THERMO-SETTING
PLASTICS
Thermoplastics variety softens
by heat and hardens when
cooled down. It can be used by
remolding as many times as
required.
Thermosetting plastics can not
be reused .This variety requires
a great pressure and
momentary heat during
molding which hardens on
cooling.

7. Thermo-plastics
 The thermo-plastic or heat non-convertible group is the general term
applied to the plastics which becomes soft when heated and hard when
cooled.
 Thermoplastic materials can be cooled and heated several times.
 They can be recycled.
 When thermoplastics are heated, they melt to a liquid. They also freeze
to a glassy state when cooled enough.
 Thermoplastic can be moulded into any shape.

8. Thermo-plastics

9. Thermo-plastics
 It may melt before passing to a gaseous state.
 Allow plastic deformation when it is heated.
 They are brittle and glossy.
 They are soluble in certain solvents.
 Swell in the presence of certain solvents.
 Good resistance to creep.
PROPERTIES

10. Thermo-plastics
 Thermoplastic materials have many features. Some products made from
thermoplastic materials are used for electronic applications. They protect
against electrostatic discharge and radio frequency interference.
 High pressure polyethylene as applied to rigid material covered with electrical
machines, tubes, etc...
 Low pressure polyethylene elastic material used for insulation of electrical cables,
etc...
 Polystyrene applied for electrical insulation, handles of tools...
 Polyamide used for making ropes, belts, etc...
 PVC or polyvinyl chloride for the manufacture of insulation materials, pipes,
containers, etc...
Examples and applications of thermoplastic plastic materials

11. Thermo-plastics

12. Thermo-setting plastics
 The thermo-setting or heat convertible group is the general term applied
to the plastics which become rigid when moulded at suitable pressure and
temperature.
 This type of plastic passes originally through thermo-plastic stage. When
they are heated in temperature range of 127 ͦC to 177 ͦC, they set
permanently and further application of heat does not alter their form or
soften them.
 But at the temperature of about 343 ͦC, the charring occurs. This charring
is a peculiar characteristic of the organic substances.

13. Thermo-setting

14. Thermo-setting plastics
 These are soluble in alcohol and certain organic solvents, when
they are in thermo-plastic stage. This property is utilized for making
paints and varnishes from these plastics.
 These are durable, strong and hard.
 They are available in a variety of beautiful colours.
 They are mainly used in engineering application of plastics.
PROPERTIES
*Melamine Crockeries

15. Thermo-setting plastics
APPLICATIONS
Epoxies
Properties: good dimensional stability, excellent mechanical and electrical
properties, good resistance to heat and chemicals
Applications: electrical components requiring strength, tools and dies,
fiber reinforced epoxies are used in structural components, tanks,
pressure vessels, rocket motor casing
Phenolics
Properties: good dimensional stability, rigid, high resistance to heat, water,
electricity, and chemicals
Applications: laminated panels, handles, knobs, electrical components;
connectors, insulators

16. Thermo-setting plastics
APPLICATIONS
Polyesters (thermosetting, reinforced with glass fibers)
Properties: good mechanical, electrical, and chemical properties, good
resistance to heat and chemicals
Applications: boats, luggage, swimming pools, automotive bodies, chairs
Silicones
Properties: excellent electrical properties over a wide rang of temperature
and humidity, good heat and chemical properties
Applications: electrical components requiring strength at high temp.,
waterproof materials, heat seals

17. Thermo-setting plastics
 Electronic chips
 Fibre-reinforced composites
 Polymeric coatings
 Spectacle lenses
 Dental fillings
General Uses

18. Natural vs. synthetic polymers
NATURAL POLYMERS SYNTHETIC POLYMER
Thermoplastic polymer
(Chemical composition do not
change on heating)
Thermosetting polymer
(Irreversible chemical process)
Remouldable Polymers Non-remouldable Polymers
These are brittle, glossy,
elasticity, flexible
They possess matt effect,
elasticity, and are flexible
Eg: Polyethylene,
Polypropylene, Polystyrene, PVC
Eg: Rubber, Nylon, Glass Fibre,
Cork

19. Structure based
Homogeneous
Plastics
Heterogeneous
Plastics

20. Homogeneous plastics
This variety of plastic contains carbon chain i.e. the plastics of this group
are composed only of carbon atoms and they exhibit homogeneous
structure.
Heterogeneous plastics
This variety of plastic is composed of the chain containing carbon and
oxygen, the nitrogen and other elements and they exhibit
heterogeneous structure.

21. Based on physical and chemical properties
Soft Plastics
Semi-rigid
Plastics
Elastomers
Rigid Plastics

22. Rigid plastics
These plastics have a high modulus of elasticity and they retain
their shape under exterior stresses applied at normal or
moderately increased temperatures.
Semi-Rigid plastics
These plastics have a medium modulus of elasticity and the
elongation under pressure completely disappears, when pressure
is removed.

23. soft plastics
 These plastics have a low modulus of elasticity and the
elongation under pressure disappears slowly, when pressure is
removed.
 Soft plastics are available in a large range of colours, sizes and
particularly shapes.
USES: Used in making children’s toys eg: rattles etc., fishing baits.

24. Elastomers
These plastics are soft and elastic materials with a low modulus of
elasticity. They deform considerably under load at room
temperature and return to their original shape, when the load is
released. The extensions can range upto ten times their original
dimensions.

25. Bio-degradable Plastics
 Biodegradable plastic decomposes in the natural environment. It is
produced from biopolymers called polyhydroxyalkanoate (PHA). This
material is completely biodegradable.
 Biodegradation of plastics can be achieved by enabling
microorganisms in the environment to metabolize the molecular
structure of plastic films to produce an inert humus like material that is
harmful to environment.
 The use of bio-active compounds compounded with swelling agents
ensures that, when combined with heat and moisture, they expand the
plastic’s molecular structure and allow the bio-active compounds to
metabolise and neutralize the plastic.

26. Bio-degradable Plastics

27. Advantages & disadvantages
 Under proper conditions biodegradable plastics can degrade to the
point where microorganisms can metabolize them.
 This reduces the problems with litter and reduces harmful effects on
wildlife.
 However degradation of biodegradable plastic occurs very slowly.
 Proper composting methods are required to degrade the plastic,
which may actually contribute to carbon dioxide emissions.

28. Moulding compounds
Some of the moulding components are:
 Catalyst
 Fillers
 Hardeners
 Lubricants
 Pigments
 Plasticizers
 Solvents

29. Catalysts
 These components are added to assist and accelerate the hardening
of resins.
 For instance, the ester acts as catalyst for urea formaldehyde.
 They are used for quick and complete polymerization.

30. fillers
 The fillers are inert materials and they impart strength, hardness and
other properties to the plastic.
 The choice of filler should be carefully made.
 It should be confirmed that the addition of a filler does not have
detrimental effect on other properties of plastic.
 The filler may be used in the following forms-
 Fibrous fillers
 Laminated fillers
 Power fillers

31. hardeners
 These compounds are added to increase the hardness of resin.
 For instance, the hexamethylene tetramine acts as hardeners for
phenol formaldehyde.

32. lubricants
 The lubricants are applied on the surface of moulds so that the
articles of plastic do not stick to the moulds.
 The application of lubricants on surface of moulds allows easy
removal of articles of plastic from the moulds.
 The commonly used lubricants are graphite, parafine, wax, etc.

33. pigments
 The addition of dyes and pigments helps in two ways, namely, they act as fillers
an they impart desired colour to the plastic.
 They should be durable and adequately fast to light.
 The commonly used pigments are zinc oxide, barytes, etc.
 The selection of pigments should be done in such a way that their addition does
not alter or affect the other properties of plastic.

34. plasticizers
 The plasticizers are the organic compounds which are oily in nature and low
molecular weight.
 They are used to separate the polymer chain by a greater distance to make the
crystallization difficult.
 These components are added to improve the plasticity and to impart softness to
the plastic.
 They gives flexibility to the material and act like a lubricant.
 The addition of plasticizers facilitates the moulding process of plastic articles.
 The commonly used plasticizers in plastic are camphor, triacetin, tributyl
phosphate, etc.
 The properties of plasticizers in plastic should not exceed 10% otherwise
strength of plastic will decrease.

35. solvents
 These components are added to dissolve the plasticizers.
 For instance the alcohol is added in cellulose nitrate plastics to dissolve
camphor.

36. Fabrication
Following are the process involved in the fabrication of articles of
plastics:
 Blowing
 Calendering
 Casting
 Laminating
 Moulding

37. blowing
 This method of lubrication of articles of plastic is more or less the same
as the one employed in the glass industry.
 A lump of plastic material is taken and by blowing, it is converted into
hollow plastic articles such as jars, bottles, toys, etc.

38. calendering
 In this process the plastic material is allowed to pass between the
cylindrical rollers.
 The process is used to prepare plain flat sheets of plastics.
 The roller may be provided with artistic designs which will appear on
the finished product.

39. calendering

40. Casting
 This process is similar in principle to that of metal casting.
 The resin is heated and when it is in plastic form, it is poured into the
mould.
 The curing of articles is then done either with or without the
application of heat.
 During curing the low pressure may be applied if necessary.
 This process is used to prepare plastics of beautiful colours and it is
most suitable for cellulose plastics.

41. Casting

42. Laminating
 In this process, the thermosetting resin are just applied on sheets of
paper, asbestos, cloth, wood, glass, fibre, etc. and they are subjected to
heavy pressure by allowing them to pass through rollers to form plastic
laminates.
 The thickness of sheets varies from 0.12 mm to 15 mm
 Due to the pleasing finished surface, they are used for ornamental and
decorative purposes.

43. Laminating

44. moulding
 This is the most commonly adopted process for the fabrication of plastic
articles.
 The general process consist in placing the raw materials in a mould and then
heating it.
 The moulding can be done by various methods:
 Compression moulding
 Extrusion moulding
 Injection moulding
 Jet moulding
 Transfer moulding
NOTE: The choice of moulding method will depend on the article to be prepared.

45. CLICK TO VIEW THE MOVIE

46. moulding
MOULDING MACHINE (PROCESS)

47. moulding
A VARIETY OF MOULDED
ARCTICLES

48. properties
 APPEARANCE: Some plastics are completely transparent in appearance. With
the addition of suitable pigments, the plastics can be made to have appearance
of variety of attractive, opaque, stable and translucent colours.
 CHEMICAL RESISTANCE: The plastics offer great resistance to moisture,
chemicals and solvents. The degree of chemical resistance depends on the
chemical composition of plastics. Many plastics are found to possess excellent
corrosion resistance. Hence they are used to convey chemicals.
 DIMENSIONAL STABILITY: This property of plastic favours quite satisfactory with
that of other common engineering materials.
 DUCTILITY: The plastics possess excellent electric insulating property. They are
far superior to ordinary electric insulators.

49. properties
 MAINTENANCE: It is easy to maintain plastic surfaces. They do not require any
protective coat of paints.
 MELTING POINT: Most of the plastics have low melting point and the melting point
of some plastics is only about 50 ͦC. They cannot therefore be used in positions having
high temperatures or to convey boiling water.
 OPTICAL PROPERTY: Several types of plastics are transparent and translucent.
 RECYCLING: The most environmentally aware people condemn the use of plastics
for the amount of pollution caused by them in disposal. The plastics used for soft-
drink bottles, milk and juice bottles, bread bags, syrup bottles, coffee cups, plastic
utensils, etc. can be conveniently recycled into carpets, detergent bottles, drainage
pipes, fencing, handrails, grocery bags, car battery cases, pencil holders, benches,
picnic tables, roadside posts, etc.

50. properties
 SOUND ABSORPTION: The acoustical boards are prepared by impregnating fibre-
glass with phenolic resins. This material has absorption coefficient of about 0.67.
 STRENGTH: An ideal section of plastics for structural member has yet not been
designed. The plastics are reasonably strong. The strength of plastics may be increased
by reinforcing with various fibrous materials.
Following considerations are responsible to discourage the use of plastics
as the structural material:
1. The plastics are costly.
2. The plastics are subject to creep under constant heavy loads.
3. The behaviour of plastics is very sensitive to the changes in temperature.
4. The stiffness of plastics is very poor

51. properties
 THERMAL PROPERTY: The thermal conductivity of plastics is low and it can be
compared with that of wood. The foamed or expanded plastics are among the leading
thermal insulators.
 WEATHER RESISTANCE: Only limited varieties of plastics can be exposed to weather.
The certain plastics are seriously affected by ultraviolet light in the presence of
sunlight. The resistance to sunlight of such plastics can be improved by incorporating
fillers and pigments which absorb or reflect the ultraviolet light at the surface. Thus
the interior of plastics is protected.
 WEIGHT: The plastics, whether thermo-plastic or thermo-setting, have low specific
gravity, the average being 1.30 to 1.40. The light weight of plastics reduces the
transport costs and facilitates fixing.

52. Add to your knowledge
The Indian Petrochemical Corporation Ltd. (IPCL), near Baroda, has put a
commercial brand of plastics, known as the ‘Koylene’. It is the lightest of all
commercial known plastics and it is available in a wide range of grades. It is tailor-
made to suit various applications such as automotive and scooter parts, box
strappings, industrial woven fabrics, ball pen refills, drinking straws, etc. This
material possesses rigidity, good gloss, ability to withstand temperatures upto
100 ͦC and easy processibility.

53. Uses of plastic
SECTION USED FOR JOINING PVC SHEET

54. ADVANTAGES of plastic
 Corrosion resistance
 Low electrical and thermal conductivity, insulator
 Easily formed into complex shapes, can be formed, casted
and joined.
 Wide choice of appearance, colors and transparencies
Ken Youssefi Mechanical Engineering 54

55. DISADVANTAGES of plastic
 Low strength
 Low useful temperature range (up to 600
o
F)
 Less dimensional stability over period of time (creep effect)
 Aging effect, hardens and become brittle over time
 Sensitive to environment, moisture and chemicals
 Poor machinibility

56. Uses of plastic
 There are more than 10000 different kinds of plastics available in the market
and their performance abilities span those of every other known material from
soft rubber to steel.
 The typical uses of plastics in building are summarized as follows:
 Bath and sink units
 Cistern ball floats
 Corrugated and plain sheets
 Decorative laminates and mouldings
 Electrical conduits
 Electrical Insulators
 Films for water proofing, damp
proofing and concrete curing
 Floor tiles
 Foams for thermal insulation
 Jointless flooring
 Lighting fixtures
 Overhead water tanks
 Paints and varnishes
 Pipes to carry cold water
 Roof lights
 Safety glass
 Wall tiles
 Water resistance adhesives

57. World consumption of plastic

58. COMPANIES-
GE, POLYGAL, GOODSALES,
SUNBEAM
COLOURS-
 NATURAL
 SMOKE
 GREEN
 BLUE
RATE DIFFERENCES-
Rates difference as per texture is Rs 15 to 20
PER SQ FT.
IT IS TRANSPORTED IN THE FORM OF ROLLS
POLYCARBONATESHEETS
USES OF POLYCARBONATE SHEETS
Market Analysis

59. SIZE - 3X100 sq ft ,4X100 sq ft (FOR 1 mm)
7X20 sq ft, 7X40 sq ft (FOR 2 TO 12 mm)
THICKNESS - 1,2,4 ,6 ,8 ,10,12 mm
PVC PANELS
Market Analysis
THICKNESS RATES PER SQ. FT.
1 MM RS. 57
2 MM RS. 65
4 MM RS. 75
6 MM RS. 95
8 MM RS. 135
10 MM RS. 140
12 MM RS. 145

60. Market Analysis

61. DOME
CONSTRUCTION
BY PVC SHEETS
Market Analysis

62. Market Analysis

63. Market Analysis
PVC DOORS

64. Seminar presented by:
Namit Mittal
Deepak Sharma
Utkarsha Singh
Pavas Sharma
(B.Arch IV SEM)
Guided By:
AR. Amrita Rastogi
Bibliography:
Book on Engineering Materials
(Author-Rangwala)
http://en.wikipedia.org/wiki/Plastic