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PLASTIC MATERIALS
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PLASTIC MATERIALS
Large and varied group
Consists of wholly or in part combination of carbon
with oxygen,hydrogen,nitrogen
and other organic or inorganic elements
Solid in finished stage or moulded stage
Liquid in manufacturing stage
Moulded by application of heat / pressure
Generally flexible
But can be made rigid,stiff,strong,weatherresistant,heat resistant,electrical resistant and if
required can be made electrically conductive also
Basic material of all Plastics is HYDRO CARBON
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PLASTIC MATERIALS
Two types of plastics are Thermo plastic andThermoset plastics
THERMOPLASTICS are either AMORPHOUS or
CRYSTALLINE in structure They form a Linear or Branched Molecular Chain
Formulated by Addition Polymerization
Available in Granules of 3x4mm Undergoes Physical change only, on Heating
Recyclable
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They are having molecules going in all
different directions and normallytransparent. They will undergo small
volumetric change when processing.
They are tougher and more flexible.
AMORPHOUS PLASTICS
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Since commercially perfect crystalline polymers are not
produced they are identified technically as semi-
crystalline thermoplastics. A crystalline area is stiffer and
stronger. It is difficult to process crystalline materials
due to high melt temperature, melt viscosity, shrinkage.
AMORPHOUS
CRYSTALLINE
SEMI-CRYSTALLINE PLASTICS
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PLASTIC MATERIALS
By adding different modifiers,additives,fillersand
Reinforcements many formulationsof Plastics are
derived (Approx.18,000)
Classification of Thermo Plastics:-
1.Commodity Plastics eg.PE,PS,PP,PVC
2.Engineering Plastics eg.ABS,PA,PC,PEEK
3.Speciality Plastics eg.Liquid Crystral Polymer
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THERMOSETS
Formulated by Condensation Polymerization.
Available in Fine Powder form.
A compound partially polymerized.
Undergoes irreversable chemical change by
application ofHEAT & PRESSURE.
Cross linked between molecules by the
reactive portion of Compound. Not reusable or recyclable.
Difficult to dispose off.
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Cross-linked
Giant macromolecule
Structurally set
Shape cannot be altered once moulded
THERMOSET PLASTICS
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Forms a Hard, Dense and Polished Shiny moulded
component.
Brittle, Highly Heat & Electrical Resistant
Has a Shelf life.
Eg. Phenol Formaldehyde
Melamine Formaldehyde
Urea Formaldehyde
Alkyds, Diallys, Polyurethane, Silicones,
Unsaturated Polyesters.
Thermosets are normally moulded by1. Compression moulding
2. Transfer moulding
3. Injection moulding
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PLASTIC MATERIALS AND
APPLICATION
Sl.
No.
Name of plastic Chief Properties Applications
1
2
Acrylo Nitrile
Butadiene Styerne
(A.B.S.)
Density = 1.05 gm./cc
Shrinkage = 0.5 %
Tm = 175 to 300 C
Cellulose acetate( C. A.) , Perspex
Density = 1.22 gm./ cc
Shrinkage = 0.5 %
Tm = 170 to 250 C
Translucent, Tough, Low
Temp.,Low Creep resistance,
Good Gloss & Aberration
resistantance,Low waterAbsorption,Good Electrical
resistant, Weatherability Fair,
Good Chemical resistance,
Electroplatable
Transparent, Tough, Costmoderate, Hard, Stiff, Surface-
Gloss good, 2.5% Water
absorption, Electrical resistance
Good, Resistance to Acids
nil,, Self extinguishing,
T.V.Cabinets,
Helmets,Grills,
Shoe heels, Slide -
rules, Automobileparts, Furnitures
Sun glass frames,
Pen barrels, Tool
handles, Brush
backs, Ornaments,
toys & Dolls
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PLASTIC MATERIALS AND APPLICATION
Sl.
No.
Name of plastic Chief Properties Applications
3
4
Nylon or Polyamide
Density = 1.15 gm./ccShrinkage =1.5 %
Tm = 250 C
Poly Acetal ( P.O.M )
Poly Oxy Methylene
Density = 1.4 gm./ cc
Shrinkage = 2.5 %
Tm = 175 to 250 C
Translucent, Tough, High
Temp., Creep resistance Good.Wear resistantance Excellent,
Good Chemical resistance,
Self Lubricating, Low Coeff. of
Friction, Self Extinguishing,
Water Absorption 4 to10%,
Electrically not Good
Translucent, Rigid, High Tensile
and Flexural Strengths, Fatigue
Resistance high, Lower
Elongation, Resistance to
Temp.&Chemical better, Impact& Aberration Resistance
Good, Dimensional Stability
Good, Lowest Coeff. Of
Friction, Self Lubricating,
Glossy, Electrically Good, Poor
Weather ability.
Gears, Cams,
Bearing surfaces,CoilForms,
Combs, Housings,
Battery Cases,
Gaskets, Soldering
Iron Handles
Gears, Cams,
Springs, Levers,
Clips, Clamps,
Housings, Bearing,
Pump Housings,Sprinklers,
Portable water
tanks, Valves,
Showerheads.
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PLASTIC MATERIALS AND APPLICATION
Sl.
No.
Name of plastic Chief Properties Applications
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6
Polycarbonate,(P.C)
Density = 1.2 gm./cc
Shrinkage = 0.6 %
Tm = 275 to 315 C
Polyethylene (P.E)
Density =0.91gm/ cc to
0.97 gm/ccShrinkage = 1.5 %
Tm = 200 to 280 C
Transparency 90%, Impact
strength High, Dimensionally
Stable, Good Chemical and Heat
Resistance, Low Coeff. of
Friction, Self Extinguishing,
Electrically Excellent, Shrinkage
uniform in all directions, Costly.
Translucent, Low density, Cheap,
Flexible, Low water absorption
(0.01%), Electrically very good,Good Heat stability, Inert to
Chemicals, Poor Weather ability.
Outdoor lighting,
Lens, Tool and
appliance housing,
Aircraft Interiors,
Automobile Lamp
housings.
Containers, Covers,
Buckets, Household
items, Toys &Furniture.
.
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PLASTIC MATERIALS AND APPLICATION
Sl. No. Name of plastic Chief Properties Applications
7 PolymethylMethacrylate
(P.M.M.A) - Acrylic
Density = 1.15 gm/cc
Shrinkage = 0.5 %
Tm = 160o C
Transparent (92%) ,Hard, Rigid, Weather
ability Good,
Dimensionalstability very
Good, Decorative
Outstanding, Excellent-
Gloss, Chemically- Good.
Lenses, Outdoorlighting, m/c
Housings, Indoor
decorative
applications, Auto tail
lamps, Stop lights,
Instrument lenses,
Name plates, Dials,
Knobs, Signal lights.
8Polystyrene
( P. S )
General purpose &
High Impact
Density =1.05 gm/cc
Shrinkage = 0.5 %
Tm = 160 3000C
Transparent ( 90%), High
Gloss, Brittle, Rigid, High
Tensile strength, Low
Elongation, Electrically-Excellent, Dim. Stability -
Good, Less Water
absorption,
Weatherability Poor,
Chemically Good
Containers,
Packaging, Toys,
Household items,
Combs, Enclosures,Tape Cassettes,
Furnitures.
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PLASTIC MATERIALS AND APPLICATION
Sl. No. Name of plastic Chief Properties Applications
9 Polypropylene (P.P)Density = 0.90 gm/cc
Shrinkage = 1.5 %
Tm = 200o C --
2800C
Translucent , , Very highTensile strength, Impact
strength and high Fatigue
resistance , flexible.
Excellent abrasion
resistance , low friction ,
poor weather ability ,excellent chemical
resistance,selfextinguishing
electroplatable.
Containers ,household items ,
hinged applications ,
battery cases , pump
parts , splash
guards, door panels ,
accelerator pedal.
10 Poly vinyl chloride
(PVC)
Density : 1.2 1.4gm/cc
Shrinkage = 0.5 %
Transparent , high impact
strength , weather ability
good , excellent chemicalresistance , electrically good
, self extinguishing , cheap ,
abrasion good , Low water
absorption.
Electrical cords ,
handle grips ,
vacuum cleanerparts , shoes , pipe
fittings , phonograph
records , chemical
containers .