MACHINERY | ALTERNATIVE COMPOUNDERS
The lower additions required have a benefit in
Schematic of the Gneuss Nano Compounding Technology Image: Gneuss
seconds to leave the nanoparticles completely embedded in the polymer. Gneuss says that, due to the extremely fast extraction of the liquid suspension carrier, there is practically no damage to the polymer.
Property changes With their very high SA:V ratios, nanoparticles can impart significant changes to the properties of the finished compound, even at low addition rates. Examples cited by Gneuss include: change of the crystallisation temperature (for faster cooling, for example) through nucleation; improved heat transfer; improved conductivity; improved mechan- ical properties; improved surface finish; and antibacterial properties. “With the Gneuss Nano Compounding Technol-
ogy, significantly better dispersion is possible compared with conventional processes,” says Prangnell. “Therefore, it is possible to achieve the same material properties with a major reduction in the quantity of additive needed. By weight, the amount of additive required to achieve the same result is between 50% and 80% lower with our new process, depending on the application.”
Right: Image showing the difference in dispersion
of BaSo4 nanoparticles in powder form and as a 0.5% suspension in water
84 COMPOUNDING WORLD | October 2019
www.compoundingworld.com
that the impact on other material characteristics is often much reduced. “In many cases, the required results are achievable with such a small quantity of additive that unwanted side-effects, such as colouration of the polymer due to the additive, are negligible. With the Gneuss process, it is for example possible to use carbon nanotubes to achieve conductivity in the polymer without the need for the polymer to be completely black. A coloured, conductive polymer is possible,” he says. Gneuss has been collaborating with SKZ, the South German Plastics Centre located at Würzburg, as well as Huntsman and several other companies on development of the Gneuss Nano Compound- ing Technology. Most of the work has involved nanocomposites based on carbon nanotubes (CNTs), although nanocellulose, barium sulphate, titanium dioxide and other additives have also been used, as well as a special additive that is incorporated into PET for production of preforms in order to make them heat up more quickly in stretch-blow moulding equipment infrared ovens. Gneuss says the equipment and process is also suitable for reactive extrusion operations. The company hopes to have at least one unit operating at a customer soon.
Recycling applications The ability to be able to handle nanoparticles also has a benefit in recycling applications, where functional fillers are used to lift performance. The effect of any functional additive, Gneuss says, is related to the active surface area of the particles, which means that the amount of additive needed should not be considered only in terms of its weight percentage in the compound. If the size of the additive particles can be reduced, so can the quantity by weight. This reduces cost but also eases restrictions when it comes to cost-effective recy- cling into products with more than token value. Gneuss says when nanoparticle additives are
introduced into plastics compounds in powder form, “around 20% of the powder (by weight)
PHOTO: GNEUSS
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104
