polymer performance

MECHANICAL PROPERTIES

mechanical properties are how a material works in relation to a force

the tougher the polymer the more resistant it is to impact. polymers need to be able to absorb impact when used as protection by dissipating energy. an example of a tough polymer is ABS

elasticity is the measurement of how a polymer can be distorted by a deforming shape and still return to its original shape afterwards. polyurethane is used for textiles that need to be elastic. some elastomers can be used for balloons and inflatable objects, here rubber or latex is used

flexibility is how a polymer can be bent and folded and if it is rigid it is considered a stiff polymer. flexible PVC is often rolled and used as a film for coverings as it is very flexible. thermoplastics are more flexible than thermosets generally

mouldability is important for polymers as it can greatly affect the production method and if the polymer can be used at all. thermoplastics can be moulded and reformed easily and are very mouldable. thermosets are normally cured and moulded cold. polymers with high mouldability are ABS and HIPS

an important property of a polymer is its ability to be cut and scored, which is affected by the hardness of the material. acrylic can be scored by can crack when machine cut, whereas HDPE and HIPS are more flexible which means they are harder to score but cut easier. an example of a polymer that has a good ability to be cut and scored is PP

PHYSICAL PROPERTIES

physical properties are displayed characteristics in a practical environment by a polymer

insulation is important for health and safety, along with food preparation and storage. most polymers are good thermal insulators but some are better than others. metal objects can used polymer handles to increase safety. some polymers, such as foams, are manufactured to have air bubbles within them, this allows for a very good insulating layer

polymers are all electrical insulators. electrical sockets are often made form thermosets as the do not melt at the high temperatures that electricity can present

polymers can have high or low melting points. thermoplastics have a lower melting point and can be reformed under heat - however thermosets burn instead of melting. a possible hazard of heating and melting plastics are the toxic and dangerous gases they can produce

polymers react to UV radiation. UV can bleach polymers used externally such as ABS. as a polymer degrades so does its mechanical properties by making it more brittle. polymers such as ASA are used instead as it retains colour and resists UV degradation. additives can be used to prevent UV degradation as well

polymer can be resistant to chemicals this is need for producing cheap packaging of products such as bleach. HDPE is chemical resistant and is often used for piping, it is also used in its sheet stock form to line landfills to stop leaching of dangerous chemicals

resistance to liquids can be dangerous as plastics such as PET can degrade overtime and leach chemicals into the water. there are some resistance and recyclable polymers though, such as HDPE

some polymers are food safe and can be used for packaging food, often in a sheet form or moulded into a tray. polymers need to create an airtight seal to preserve the contents and avoid tampering

black polymers can be a problem as they cannot be identified by scanners sometimes as they used black conveyor belts, this is bad as black is used as a colour to control thermal absorption and radiation

transparency is used in polymers for aesthetic reasons and windows. it is also useful for packing products that need to be seen by the customer

polymers are self finishing as they are formed with heat and don’t require sanding. they also gain their colour from pigments and not paint. they can also have preproduction chemicals added to affect their outer layer, reducing extra post-production work and costs

ADDITIVES

additives are used to aid manufactured and the use of polymers, similar to alloys for desired properties in metals.

plasticisers make polymers flow more and mean they can be worked at higher temperatures. they also make the final product more stretchy and flexible

thermal antioxidants are used to stop oxidation in manufacture, antioxidants can also be used to stop cracking and degradation in air

UV light stabilisers can be used to reduce and stop the impact of UV exposure

fire retardants can be used to make a polymer more fire resistant

anti static additives are used to reduce the build up of charge

additives can be added for biodegradability, this tops them assimilating in the soil and polluting. bio-batch materials biodegrade and can be broken down quickly and safely by natural bacteria