Different Polymers And Their Uses.

by nukelearswede (student)

Designer Polymers

Shape Memory Polymers:

Shape Memory Polymers is a smart material which changes in response to its environment, E.G. the wrapping on a DVD cover is a shape memory polymer. In short, Shape memory polymer is Shrink-Wrap.

Shrink Wrap is made from Polymers, here are some steps on how it is made; -Heat the Polyethene until it becomes a soft and floppy thick liquid. The molecules are now coiled together randomly -Cool the liquid quickly, as it cools, quickly stretch the polymer to make a thin film of solid, the molecules are now stretched -Heat the thin film. The stretched molecules suddenly return to their coiled shaped. The film shrinks and wraps tightly around the DVD case

Waterproof Clothing:

Waterproof clothing is made from Polymers

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Waterproof Clothing:

Waterproof clothing is made from Polymers

Clothing can be made waterproof by Synthetic Fibre (E.g. Nylon) Nylon stops water getting in, it’s strong so it stops water vapour coming in. The Breathable waterproof clothing has 3 layers, (shown in diagram), Wet outer layer, the middle layer is made of polymer called PTFE and a Dry Inner Layer. PTFE has a large number of very small holes called pores. There are over 1 billion holes per square centimetre which are too small to let liquid water pass through which makes the film waterproof. The holes are big enough to let water vapour through, which lets sweat escape through the clothing making it breathable.

HDPE:

HDPE stands High Density Polyethene -They are made from ethane monomers but are formed under different conditions, but are formed under different conditions, they have a straight polymer molecule, there structure is closely packed, therefore forces between chains are stronger -They have a higher softening temperature then a LDPE, there density is 0.95 grams per cm². The maximum temperature which it can be used at is 120°C and it is a stiff structure which can be used on plastic chairs

LDPE:

LDPE stands for Low density Polyethene -Polymer molecules have side branches, this prevents from lining up in a pattern so the density of it is lower

LDPE Advantages:

•Cheap, Good Chemical Resistance, High Impact Strength at Low Temperatures, & Excellent Electrical properties

LDPE Disadvantages:

•Weak Strength, Weak Stiffness, Weak Maximum Operating Temperature, Flammable, Poor UV Resistance

Hydrogel’s:

A hydrogel is an example of a smart material. It can change its structure in response to salt concentration, pH and temperature. Normally the polymer chains are coiled up, but if you take away the sodium particles the chains uncoil, water molecules are attracted to the uncoiled chains and the hydrogels absorbs upto 500 times its own weight in water, This ability to absorb so much water makes the hydrogel useful for the lining of babies' nappies

By Andriy Zapotichny 10.4