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Typical uses for polythene include plastic shopping bags and plastic bottles, while polystyrene is typically used for insulation and protective packaging.

Nylon has some properties:

• tough
• lightweight
• waterproof.

Unfortunately, nylon does not let water vapour pass through it either. This means nylon waterproof clothing traps sweat, so that after a while the inside of the clothing becomes wet and unpleasant to wear.

Gore-Tex®

Gore-Tex has the desirable properties of nylon, but is also 'breathable'. It lets water vapour from sweat pass to the outside, but it stops rain drops from passing to the inside. 

Many of these polymers are not biodegradable - microbes cannot digest them and they take a long time to break down. Polymers are usually disposed of by burying them in landfill sites or burning them in incinerators.

Atoms in plastics are held by strong covalent bonds.

Weak intermolecular forces of attraction -> Polymer stretches

Strong intermolecular chemical bonds -> Polymer is rigid.

Gore-Tex contains layers of nylon, PTFE and polyurethane. The PTFE contains a lot of tiny holes called pores. Each one is too small for water droplets to pass through, but big enough to let water molecules from sweat out.