Co-Polymer: Two unlike monomers joined together in a polymer chain. E.g. Poly Vinyl Acetate

Elastomer: A group of polymers consisting of linear chains that are coiled, entangled and are subject to cross linking. This allows these materials to be very elastic at room temperature.

Lubricants: Make the polymer easier to mould. Various types of waxes are used in small amounts.

Pigments: Give the Polymer colour

Stabilisers: Stabilisers are substances which stop a polymer ageing. They improve resistance to heat and light.

Vulcanisation: Natural rubber is processed with sulphur to form cross links between chain molecules to improve wear resistance and life. It is less flexible that natural rubber which is soft.

Van Der Waals Forces: Weak secondary bonds. May be disrupted by heat.

Van Der Waals Forces vs. Cross Links
Van Der Waals Forces vs. Cross Links