Additives are materials that are added to polymers to impart desirable properties without significantly altering the polymer's molecular structure. They are used to improve processing, increase stability and resistance, and control properties like hardness, surface tension, color, and flame resistance. Common types of additives include fillers, antioxidants, heat stabilizers, UV stabilizers, colorants, antistatics, flame retardants, cross-linking agents, blowing agents, lubricants, and impact modifiers. Additives are important for attaining properties required for various applications, especially in packaging where they can enhance barrier properties, transparency, printability, and antimicrobial effects.

1. ADDITIVES IN PLASTICS
By - Kirtan .V
Roll – MO7049

2. What are
What are
additives ?
additives ?
Materials
Materials 
 dispersed
dispersed 
 polymer
polymer
matrix without affecting
matrix without affecting
significantly the molecular structure
significantly the molecular structure
of the polymer to attend certain
of the polymer to attend certain
desirable properties
desirable properties

3. Why to use additives in
plastics ?
• Improve processing conditions
• Increase resin’s stability to oxidation
• Obtain better impact resistance
• Increase or decrease hardness
• Control surface tension
• Facilitate extrusion moulding
• Control blocking
• Reduce cost
• Increase flame resistance.

4. Types of additives
• Fillers
• Antioxidants
• Heat stabilizers
• UV stabilizers
• Colorants
• Antistatics
• Flame/fire retardants
• Cross-linking agents
• Blowing agents
• Lubricants
• Impact modifiers
• Processing aids

5. What are fillers?
• Mostly needed by thermosets,
sometimes also needed by
thermoplastics.
• Added to reduce cost.

6. Classification of fillers
• Mineral fillers : e.g.
Mineral fillers : e.g. CaCO3
CaCO3 , kaolin, feldspar, talc etc.
, kaolin, feldspar, talc etc.
• Metallic, conductive & magnetic fillers : iron, copper,
Metallic, conductive & magnetic fillers : iron, copper,
zinc & lead
zinc & lead
• Fire retarding fillers :
Fire retarding fillers : Sb2O3
Sb2O3
• Organic and special purpose fillers : carbon black, wood
Organic and special purpose fillers : carbon black, wood
flour, walnut flour
flour, walnut flour
• Flake reinforcement : mica
Flake reinforcement : mica
• Continuous filament reinforcement : fibre glass,
Continuous filament reinforcement : fibre glass,
carbon graphite filaments etc.
carbon graphite filaments etc.
• Short fibre reinforcement : asbestos
Short fibre reinforcement : asbestos

7. Heat stabilizers
• To prevent degradation that occur during high
temp processing/fabrication.
• PVC largest consumer.
• e.g.- family of lead salts, complex barium cadmium
solids, non toxic Ca & Zn salts

8. • Type: Ba / Cd - Clear calendered products, Injection
moulded flexible products, blown film
• Type: Ba / Cd / Zn – Clear calendered products, blown film,
flexible products, plastisol processing
• Type: Ba / Zn – Flexible calendered products, unsupported
films for garments, artificial leather for automotive
• Type: Ca / Zn (Non-Toxic) – Children’s toys, packaging films,
base coat for artificial leather, top coat for floor
coverings, conveyor belts, sealing compounds
• Type: Ba / Cd / Pb – Calendered, injection moulded
products, extreme high temp, and application.
• Type: Lead Complex – Rigid PVC pipes, casing capping,
electric wires.

9. UV STABILIZERS
• UV light  280-400nm  polymers unstable
• To overcome this UV stabilizers are used.
Classification-:
1)UV absorbers: Hydroxy benzophenones
2)UV quenchers: Piperidines
3)Pigment: carbon black
Applications -:
1) carpenting outdoor/seatings
2) Acrylic coating used on outdoor sign boards
3) Light diffusers
4) Used in outer liners of HMHDPE

10. Antioxidants-:
• Polymers when subjected to oxygen attack & if
1)there exists high concentration of unsaturated c-c bonds
2)residual polymerisation catalyst
3)it is subjected to highly oxidising conditions,then it undergo
oxidation.
-to overcome this problems  long service life, antioxidants
are used.
Classification -:
1)primary: hindered phenolics acryl amines
2)secondary: phosphurous &
sulphur containing compounds

11. Colorants
properties :
1) hiding power
2) particle distribution
3) fastness to light,heat,chem.
e.g. Benzidine yellow, red 2B pigments,
Alumina hydrate, iron oxide .
Applications:
Packaging, domestic articles, space research ,
m/c switches, transportation
Colorants
Dyes (completely soluble)
Pigments (forms dispersion)

12. Antistatic agent
• Due to low surface conductivity  have poor
conductivity  accumulation of static charge.
Which is undesirable because
1) attracts dust particles wear & abrasion &
unsightly look.
2) charged metals results into powdering.
3) it can generate spark, which can become
hazardous.
e.g. butyl stearate, tri -ethanol-amine

13. Fire retardants
• Polymers being organic compounds burn or
decompose on exposure to fire, generates toxic
fumes, smoke.
• Two techniques: 1)use fire retardant raw material.
2)use fire retardant additives.
e.g. inorganic :zinc borate
halogenated :chlorinate paraffins
applicable to polymers to be used in mines,
automobiles, air vehicles, railways, etc.
consumed by - polyesters, polycarbon
polyurethanes.

14. Cross-linking agents
• Thermosets cure either on application of heat or cross
linking/curing/ hardening agents.
• In some cases agent triggers off the reaction & therefore
linking the resin molecules or
• It enters into the parts between molecules and completes
the chain.
Classification :
1)free radical intiator : Isobutyl nitrile, Alkyl peroxide .
2)non free radical agents : Isocynate with polyol
Used : Manufacture of Thermosets like polyurethane,
Urea Formaldehyde, etc

15. Blowing agent
• Polymeric foams preparation(2 ways)
1) mechanical
2) chemically
• substances called blowing agents, which on heating
decompose giving N & CO2
• Rigid PVC,ABS,Polystyrene, polyolefins being chief
consumers.
Applications:
mattresses, pillows, insulation, foam pipes
for non-p conditions.
e.g.para toluene sulphonyl hydrazide.

16. Lubricants
• Hot processing of polymers need lubricants either internally
or externally.
• Internal lubricants decreasing normal cohesive forces
between polymer moleculesgood flow conditions by
lowering viscosity.
• External lubricant don’t let melt to stick to hot surface of
processing. By forming a thin layer at melt-solid interface.
e.g. butyl stearate, octyl stearate, stearic acid

18. Impact modifiers
• To upgrade physical properties of polymer to the extent
prescribed by consumer, the additives added to polymers
are called as strength (impact) modifiers.
• They impart breakage resistance, rigidity, ease of post
fabrication, strength to sheets
• The strength imparted depends on time & temp conditions
of processing .
• Rigid PVC for prolonged outdoor exposure needs I.m.,
similarly epoxy & polyester thermosets require impact
modifiers.

20. Additives : Packaging
appications
• Enhances barrier properties
• Better transparency/Gloss
• Better printing/sealing properties
• Anti microbials

21. Thank you ;)