Dispersing functional fillers in polymers

Materials World magazine
1 Oct 2008

Polyfect, a spin-out company from Loughborough University, UK, hopes to license a technology for dispersing functional fillers to improve the mechanical quality and reduce the weight and cost of polymer products. This could benefit applications such as automotives, packaging and electronics, where fillers enable electrical conductivity, fire retardancy, pigmentation, or barrier and anti-static properties. The technique could also be applied to polymer composites that incorporate carbon fibres or nanotubes.

The company is still filing its patents and is unable to discuss the details of its process, however, CEO Ian Balchin insists it is ‘a platform technology’. He says it is not chemical based and will improve the dispersion of functional fillers, such as carbon black, by up to 10 times.

He explains that conventional techniques such as mechanical mixing using single or twin-screw extrusion, or chemical surfactants, are unable to overcome the agglomeration of the filler particles. This requires more filler to achieve the desired properties.

‘In some applications, you need 20-30% of carbon black to get the electronic and semiconducting properties, and it is typically four times the cost of the polymer,’ explains Balchin.

‘The increase in filler material also has an adverse impact on the mechanical properties of the final article, mostly on tensile strength and elasticity. If you want to have the electrical properties and mechanical strength, you have to have a bigger component than you would otherwise need.’

Increasing the efficiency of dispersing filler material will therefore reduce the quantity required and, in turn, the costs involved. It will also improve the mechanical properties and allow for lighter products.

Balchin adds, ‘[Automotive manufacturers] are particularly looking at light weighting for fuel economy. And people who are making films are also looking to get the gauge as thin as possible while having the mechanical strength they need’.

Polyfect is scaling up the technology in-house and insists that the amount of energy consumed is comparable to,and not greater than, existing processes. Moreover, the potential to decrease material use is environmentally appealing in a climate of soaring raw material and fuel costs.

The firm is initially looking to work with select organisations that recognise the technology’s potential and wish to be the first to trial it.

Further information

Ian Balchin