Polyethylene 500, better known as HMW-PE, is a high molecular weight material, which offers better wear resistance and impact strength compared to HD-PE.
HMW-PE has a density of 0.95 g/cm³ and a molecular weight of 500.000 mol/g. Thanks to this higher density, mechanical characteristics are highly improved and at the same time machinability is improved too.
This kind of Polyethylene is quite stiff and has a good wear resistance with a low specific gravity. It can afford better sliding properties, even is its stiffness causes a loss of few mechanical properties, such as flexural strength and compression and yield stress. Polyethylene 500 is not a good material for damping applications, but its better suggested for low load application with a minimum wear.
We highly suggested not to us HMW-PE for high precision components, because its coefficient of thermal expansion could cause huge deformation on dimensions.
High Molecular Weight Polyethylene has a great chemical resistance and its properties can be compared to those ones of HD-PE.
So, it is resistant to acids, alkaline solutions, salts and salt solutions, alcohols, oils fats, waxes and many solvents. Aromatics and halogenated hydrocarbons cause swelling. All PE types are not resistant to strong oxidising materials (such as nitric acid, chromic acid or halogens) and there is a danger of stress corrosion cracking.
This material is also available in Food grade, which can be certified according EC 1935/2004, EC 2023/2006 and EU 10/2011. FDA certification is also available upon request.
High Molecular Weight Polyethylene is usually produced in rods and plates from different companies, each one with its own commercial name. Although that, each HMW-PE has more less the same characteristics and can easily substitute one each other.
Most famous brand names are: