In contrast to the conventional
compounding process, where the compound
should be pelletized and fed into the injection
molding machine for the second plasticizing
process, the injection molding compounding
combines both these two processing steps.
The unique Montanuniversitaet Leoben
Polymer Nano-Composite Injection Molding
Compounder (MUL PNC-IMC) includes an
extruder to produce melt and an injection
device which is fluidly connected to the outlet
of the extruder. The material compounding
and the subsequent injection molding are
done directly “by only one plasticizing
process” using heated melt pipe and a melt
accumulator. The compounding extruder is a
co-rotating, self-cleaning twin-screw extruder
capable of high performance plasticizing,
uniform melting and good mixing. The melt accumulator holds the continuously extruded melt during the
injection and holding phases. The injection unit is engineered for high working capacity. The melt is fed to the
font face of the injection screw. The shot volume is injected completely, so that there is no residue build up. All
the flow channels are completely emptied in every cycle and the melt dwell times are short. The melt
accumulator separates the transfer valve and the injection unit, so that maximum injection pressures can be built
up. An overview of the work on the injection molding compounding technique at the Institute of Injection
Molding of Polymers, Montanuniversitaet Leoben is described in this article. The comparison of different
processing and compounding techniques and their influence on mechanical properties are discussed. Both
conventional processing of polymer nanocomposites and processing in PNC-IMC are evaluated. The effects of
carbon footprints by these processing strategies are investigated. The results give a good overview on the
possibilities of the concept of PNC-IMC.