Natural rubber and vulcanisation Tamil revision mind map: latex as a colloidal suspension of rubber particles stabilised by a charged protein and lipid layer, isoprene as the monomer with the resulting cis-1,4-poly(isoprene) chain structure giving natural elasticity, the limitations of raw rubber being soft, sticky when hot and brittle when cold because chains slide freely, vulcanisation with one to three percent sulphur forming cross-links at the double bonds to lock chains together, and the resulting harder stronger more elastic rubber plus additives such as carbon black filler and zinc oxide accelerator used in tyre manufacture.