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strength, toughness and dimensional stability. Commonly used reinforcements are
Carbon, asbestos, aramid or graphite fibers which can be continuous, chopped,
milled or stapled, Nylon or Pet fibers, fabrics and wood floor.
Coupling Agents: Most polymers are non-polar (hydrophobic) substances and are
not compatible with inorganic materials used as reinforcements and fillers.
Coupling agents are used in small quantities to treat a surface to bond them more
firmly together and improve strength. While they are usually applied to the inorganic
surface before compounding, they are sometimes added directly during
compounding. Coupling agents significantly improve mechanical and electrical
properties while also lower composite cost by achieving higher mineral loading.
Compatibilizers: When two or more polymers are blended together, either
recycled or other in blends and alloys, often they are not compatible with each other
resulting in insufficient properties for most end uses. Compatibilizers are thus
added which reduce interfacial energy between two polymers in order to increase
adhesion. Its addition provides finer dispersion and more regular and stable
morphology thereby increases mechanical performance and surface properties.
Antifogging Agents: A group of additives (mostly surface-active compounds)
which are added to films or sheets in order to eliminate fogging and/or dripping that
is caused by excess humidity
Cling agent: Packaging films used in stretch wrapping, require incorporation of
cling additive to achieve desired elasticity and tackiness in the film which effect self
adhesion of the wrap without any external aid. Two most common cling agents are
polyisobutene (PIB) and atactic polypropylene (APP), PIB being more widely used.
Optical Brighteners: Many plastics have tendency to yellow due to degradation by
UV or visible light.
The breakdown products absorb blue light, giving a yellow appearance in daylight.
Optical brighteners are designed to brighten colours or mask yellowing. They work
via a fluorescent mechanism, absorbing light in the UV spectrum and emitting it in
the blue range of the visible spectrum making whites appear 'brighter' to the human
eye.
Tinopal® is one of commonly used optical brighteners for plastics.
Purge Agents: Purging compounds are used by processors to clean out polymer,
colour and other impurities from the machine and tooling between production runs.
There are three general kinds of purging compounds: chemical, abrasive and non-
abrasive. They save on time and material wastage and also enhance equipment life
by flushing out carbon build ups within.
Additives: Future Opportunities and Growth areas
Plastics additives industry is always looking for new effects and performance like:
• Barrier properties at low cost
• UV protection of goods to improve shelf-life
• Improved shelf-life of foods
• Permanent antistatic performance
• Transparent products for aesthetic / price ratio
• Smart and intelligent packaging

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