What is C6?
C6 is shorthand for the Hexene comonomer used in the Linear Low Density Polyethylene (LLDPE) plastic from which the water tank is made.
In LLDPE, the branching in the molecule is achieved through copolymerisation with comonomers such as either butene-1 (C4), hexene-1 (C6) or octene-1 (C8). These comonomers respectively give ethyl, butyl and hexyl branches. The toughness of the LLDPE is highly dependent on the short chain branch length, which is determined by the comonomer used. A C6 comonomer has a longer short chain branch length than a C4 comonomer, and so on.
The degree of branching increases as the proportion of comonomer in the polymer is increased. The branching structure will hence depend on the type and proportion of comonomer, and also the distribution of comonomer along the molecule (ie. whether the branches are evenly distributed or clumped together) and between molecules. This means that the LLDPEs supplied by different manufacturers can have noticeably different properties.
In Alkatuff LLDPE, which is a hexene-1 copolymer, the branch points occur every 50 to 100 carbon atoms (10 to 20 methyl groups per 1000 carbon atoms).
Alkatuff is made with a hexene (C6) comonomer, giving superior impact strength, stress crack resistance and long-term toughness than tanks made with a standard butene (C4) resin.
