1.
Fundamentals of Polymer Engineering
Polymer Additives and Blends
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Course Code: PE-3107
Credits: 3-0-3
Teacher: Engr. Asra Tariq
Email Id: asra.tariq@ntu.edu.pk

2.
Additives
 Plastic materials have a wide application range
- Automotive industry
- Electronic sector
- Packaging industry
- Manufacturing of consumer goods
 All these industries are attributed to the incorporation of additives
- Additives are added into
Virgin
Recycled resins
 Polymer industry is impossible without additives
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3.
Additives
 Any Substance that is added generally in small concentration to resins in
order to :
 Improve their properties
 Facilitate processing
 Change the physical, chemical or electrical properties of end products.
 Reduce the cost
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4.
Requirements of Additives
 Effectiveness in their function
 Stable under processing conditions
 Stable under service conditions
 Economic
 Compatibility with Polymer Matrix
– At molecular level
 Neither Volatile nor extrude to the surface
 Neither bleed nor bloom
 Must have low vapour pressure at high temperature
 Non Hazardous, not impart taste & odour
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5.
Classifications of Additives 5
Classifications of Additives
Assist
Processing
Processing
Stabilizer
Lubricants -
External
Lubricants -
Internal
Reduce Cost
Fillers
Diluents &
extenders
Modifying
bulk
mechanical
Properties
Reinforcing
filler
Plasticizer
Toughening
Agents
Surface
Properties
Modifiers
Antistatic
Anti Slip
Anti wear
Adhesion
Promoters
Optical
Properties
Modifiers
Nucleating
Agents
Colorants
Anti-aging
UV
Absorbers
Fungicides
Others
Flame
Retarders
Blowing
Agents

6.
Polymer Compounding
 Few polymers are used in pure form since they often
require chemical modification to achieve optimum
properties, and promote non-inherent performance.
 The process of adding essential ingredients to polymers
to achieve these results is termed compounding.
 Compounds must behave as a system, consisting of the
base polymer and additives, selected to achieve a set of
final properties. During compounding, mixing must
occur at two fundamental levels; dispersive mixing and
distributive mixing.
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7.
Additives in Polymer Industry
 Additives in plastics provide the means to overcome
- Processing problems
- Property performance limitations
- Restricted environmental stability
 Additives can mean ingredients for plastics but they play a crucial
role in other materials such as
- Coatings
- Lacquers
- Paints
- Printing inks
- Photographic films
- Papers
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8.
Additives in Plastics
 Plastic additives are a diverse group of specialty chemicals that are
either incorporated into the plastic
- Before processing
- During processing
- Applied to the surface of the product when the processing is completed.
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9.
Additives in Rubbers
 Rubber is a thermosetting polymer which requires curing
(peroxides) in a reaction
The reaction must be controlled by
- Initiators (e.g. sulphur compounds)
- Accelerators (e.g. aniline)
- Retarders, etc.
 The whole compounding and moulding process is to be controlled
by
- Antioxidants
- Antiscorch agents to prevent decomposition
 Plasticizers are added to improve processability
 Adhesion promoters may be added to improve the bonding with
reinforcement
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10.
Additives in Rubbers
 To protect cured rubber products during lifetime other additives are
added to provide the resistance from
- Ozone
- Ultraviolet
- Internal heat build-up as the compound is stressed
 Other vital components of a final rubber compound are
- Fillers as reinforcing agents
- Pigments
- Extenders (Low cost fillers)
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11.
Fillers
 Fillers are used to extend a material and to reduce its cost
• Few inexpensive fillers are still being used purely for filling purpose
such as
- Walnut shells
- Fly ash
- Wood flour
- Wood cellulose
• Basic low-performance materials such as clays and chalks are still
used very widely
• Modern market demands that fillers should give some additional value
such as improvement in the mechanical properties beside extending
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12.
Function of Fillers
• The basic purpose is to fill a compound
- Increase bulk at low cost
- To do this the mix must be homogenous
•Should have good filler-polymer adhesion
The filler also begins to improve the mechanical properties
• Most particulate fillers have a higher specific gravity than polymers
In some cases the addition of fillers can reduce the weight of the compound
- By using the low density filler as compared to polymer
- Adhesion properties are influenced by
• Filler geometry
• Surface texture
- These can be improved by surface treatment
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13.
Fillers
Materials/Characteristics
Fillers that have a reinforcing effect are
- Clays
- Calcium carbonates
- Talc
- Silicates
Pigments such as
- titanium dioxide
- Carbon black
Fillers that offer good properties are
- Glass
- Ceramic microspheres
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14.
Fillers
For Commercial Polymer
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15.
Polymer Blends
 A polymer blend, or polymer mixture, is a member of a class of
materials analogous to metal alloys, in which at least two polymers are
blended together to create a new material with different physical
properties.
 Polymer blends are physical mixtures of two or more polymers
with/without any chemical bonding between them. The objective of
polymer blending is a practical one of achieving commercially viable
products through either unique properties or lower cost than some other
means might provide.
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16.
Polymer Blends
 The various economic and property advantages accomplished by blending are
• The opportunity to develop or improve on properties to meet specific customer needs
• The capability to reduce material cost with or without little sacrifice in properties
• Permit the much more rapid development of modified polymeric materials to meet
emerging needs by by-passing the polymerization step
• Extended service temperature range
• Light weight
• The ability to improve the processability of materials which are otherwise limited in
their ability to be transformed into finished products
• Increased toughening
• Enhanced ozone resistance
• Improved modulus and hardness
• Improved barrier property and flame retardant property
• Improved impact and environmental stress cracking resistance, etc.
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17.
Polymer Blends
 Types of Polymer Blends
On the basis of miscibility
Basically there are three different types of blends depending on the
miscibility
 Completely miscible blends
 In partially miscible blends
 Fully immiscible blends
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immiscible blends

18.
Polymer Blends
 Examples of miscible polymer blends:
 homopolymer–homopolymer:
 polyphenylene oxide (PPO) – polystyrene (PS): The miscibility of the
two polymers in l is caused by the presence of an aromatic ring in
the repeat units of both chains
 polyethylene terephthalate (PET) – polybutylene terephthalate (PBT)
 poly(methyl methacrylate) (PMMA) – polyvinylidene fluoride (PVDF)
 homopolymer–copolymer:
 polypropylene (PP) – EPDM
 polycarbonate (PC) – acrylonitrile butadiene styrene (ABS
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