C6: The key to a strong polyethylene water tank

A polyethylene water tank is a valuable, long-term investment, meaning there is a list of things to consider when purchasing one.

Aside from the obvious aspects such as tank shape, size and colour, it's vital you consider the less visual or tangible factors as well. The structural integrity of your tank is of paramount importance, and a tank built from high-quality polyethylene will give you years – if not decades – of reliable service.

But what makes a good polyethylene? An easy check to perform is to find out whether it is made with a C6 comonomer.

Polyethylene is typically copolymerised with a comonomer for the purpose of adding molecular weight and strengthening the material. The comonomer affects to the molecular branching structure of the polyethylene, which in turn impacts the strength and durability of the plastic.

A C6 – or hexene – comonomer has a longer short chain branch length and higher molecular weight than a C4 (butene) comonomer, which is found in many other poly water tanks on the market.

While these differences may seem minute and difficult to grasp, the real-life effects are immense. A polyethylene with greater molecular weight and stronger branching will offer enhanced impact strength, greater stress crack resistance and better long-term durability overall.

Moreover, in a country such as Australia where vast fluctuations in temperature can increase the threat of creep and stress cracking, these properties are certainly appreciated.

If you're in the market for a poly water tank for your home, make sure you ask for one that features a C6 comonomer. Choosing a tank made from Alkatuff polyethylene will ensure you can enjoy this advantage, while also offering other benefits such as superior UV resistance.

By David Francis