IX Международная студенческая научная конференция Студенческий научный форум - 2017

Every activity in modern life is influenced by plastics and many depend entirely on plastics products. Imagine cars without synthetic bumpers, dashboards, steering wheels and switches. Imagine medicine without plastic hypodermic syringes and artificial hip joints. Telecommunications are dependent on plastic phones, circuit boards, and cable insulation. Our entertainment and leisure relies on the unique combination of characteristics offered by plastics in sports equipment and clothing, CDs, video and audio tape, television and cinema. You would not be able to read this over the internet without plastics!

All these plastics products are made from the essential polymer mixed with a complex blend of materials known collectively as additives. Without additives, plastics would not work. With additives, plastics can be made safer, cleaner, tougher and more colorful. Additives cost money, of course, but by reducing production costs and making products last longer, they help us to save money and conserve the world's precious raw material reserves. In fact, our world today would be a lot less safe, a lot more expensive, and a great deal duller without the additives that turn basic polymers into useful plastics.

One way to improve the performance characteristics of plastic products is to compound resins with additives and fillers. Additives help fight against factors such as heat, chemicals, or light. There are thousands of additives/fillers on the market today. Below are some of the most common ones used in manufacturing.

A multitude of polymer additives are added to commercial polymers in order to enhance performance and achieve various functional properties and accordingly demands stringent analytical expertise.

Additive analysis for polymer materials can be challenging due to the complexity of the materials: the presence of various groups of additives, compounding ingredients, and fillers all in one sample.

Chemical identification of polymer additives is essential to all parts of the plastics supply chain as additives can impact both the functional properties of the materials and the production cost of polymers. Robust quantification of polymer additives is also required.

Anti Counterfeiting:

Function: There are a number of ways manufacturers and brand owners can combat counterfeiting by employing one of several or indeed multilayer anti-counterfeiting technologies. Optical brighteners absorb ultraviolet and violet light then re-emit this energy at a higher wavelength, normally as a blue glow.

Antimicrobials/Biostabilisers

Function: Help prevent deterioration of plastic materials where part of the material might be susceptible to microbiological attack. Such attacks can cause staining, discolouration, odour and loss of aesthetics but more importantly, loss of electrical insulating properties, hygiene and overall loss of mechanical properties in the material. Used to control the build up of bacteria, fungi and algae on the surface of plastic products. A wide range of chemical and natural compounds are used as antimicrobials. An example would be naturally occurring silver ions used in products such as cell phones or organic acids in food-related products.

Antioxidants

Function: Used to control the degradation of products due to air exposure. Help prevent "oxidation", the polymer reacting with oxygen. Oxidation can cause loss of impact strength, elongation, surface cracks and discolouration. Antioxidants help prevent thermal oxidation reactions when plastics are processed at high temperatures and light-assisted oxidation when plastics are exposed to UV light.

Antistatic Agents

Function: Used to minimize static electricity. These types of additives can be mixed with the resin or applied to the surface of the product. Antistatic additives are common to a wide variety of products ranging from cosmetics to industrial goods to sensitive electronic parts. Help to prevent the build up of static electric charge. Plastics are generally insulating and so have the capacity to build up static charges on the surface which greatly disturb processing procedures and can be an issue for hygiene and aesthetics.

Biodegradable Plasticisers

Function: Used to make plastics softer and more flexible and to enhance the degradability of the product.

Blowing Agents

Function: Form gases in the plastic to produce a foam material. The blowing agents form gases by breaking down on heating at a pre-determined temperature and form a foam structure within the plastic's polymer matrix.

External Lubricants

Function: Used for easier molding or for increased adhesion and viscosity of the molded parts. To prevent damage to plastics or the mould during processing. Applied to the material or directly to the machine to allow processing without damage.

Fillers/Extenders

Function: An inexpensive substance such as wood, metal, glass or clay that is added to plastics in very small particles to decrease cost, improve hardness, stiffness, and impact strength. Natural substances used to improve strength and lower the cost of the material. Usually mineral-based, fillers/extenders literally increase the overall "bulk" of the plastic.

Fragrances

Function: Fragrances and deodorants for plastics are used in a variety of applications and arer products for the home.

Heat Stabilisers

Function: To prevent decomposition of the polymer during processing. Processing usually results in temperatures well above 180 deg celsius, which without the addition of heat stabilisers would result in the plastic material literally falling apart.

Impact Modifiers

Function: Enables plastic products to absorb shocks and resist impact without cracking. Particularly relevant for polyvinyl chloride (PVC), polystyrene (PS) and polypropylene (PP) materials.

Internal Lubricants

Function: Used to improve processability of plastics by increasing the flowability. Internal lubricants improve the melt flow of material by lowering the viscosity and heat dissipation (also see Processing Aids).

Light Stabilisers

Function: Used to inhibit the reactions in plastics which cause undesirable chemical degradation from exposure to UV light.

Pigments

Function: Tiny particles used to create a particular colour.

Plasticisers

Function: Added to make products softer and more flexible. Some plasticizers evaporate and tend to concentrate in an enclosed space; the "new car smell" is caused mostly by plasticizers evaporating from the car interior.

Fibers

Function: Used to increase strength and stiffness. The most common type of fibers added for strength would be carbon and glass. Glass-reinforced plastic is more commonly known and marketed as fiberglass.

References

1. John Murphy Additives for Plastics Handbook (Second Edition) Elsevier Science, 2001, p.484

2. Carreau, P. J., D. C. R. De Kee, and R. P. Chhabra, Rheology of Polymeric

Systems—Principles and Applications, Hanser Publishers, New York, 1997, p. 52.

3. Malloy, R. A., Plastics Product Design for Injection Molding, Hanser Publishers, New York, 1994, p. 68.

4. Bernhardt, E. C., Processing of Thermoplastic Materials, Reinhold Publishing Corporation, New York, 1959, p. 157.

5. Rosato, D. V., and D. V. Rosato, Plastics Processing Data Handbook, Chapman & Hall, New York, 1989, p. 93.

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