Optimization of Extrusion Parameters for Preparing PCL‐Layered Silicate Nanocomposites Supported by Modeling of Twin‐Screw Extrusion

Abstract

PCL‐based nanoclay (layered silicate) nanocomposites are prepared using a small scale intermeshing co‐rotating twin‐screw extruder. Improving the level of nanoclay dispersion in PCL nanocomposites is obtained by changing the extrusion parameters. Increasing the screw speed and decreasing the throughput leads to an improved dispersion quality, as observed from the improved mechanical properties of the nanocomposites as well as from their clearly affected rheological and crystallization behavior. Furthermore, a commercially available software that simulates the twin‐screw extrusion process (LUDOVIC) is used to asses the processing parameters applied for making the nanocomposites.

In-Line Rheo-Optical Investigation of the Dispersion of Organoclay in a Polymer Matrix during Twin-Screw Compounding

“…Increasing the molecular mass of the polymer (i.e., the hydrodynamic stresses) had no effect on the melt intercalation [ 17 ]. Contrarily, heating the barrel (thus, lowering the stresses) yielded a better clay dispersion [ 18 ]. Furthermore, the leveling-off of clay dispersion or even a reversion of dispersion at larger screw speeds or feeding rates has been reported [ 11 ].…”

“…Yet, the few studies on the impact of the feed strategy on clay dispersion document controversial results. Masterbatch dilution was reported to be more effective than premixes in exfoliating clay [ 21 , 22 ], whereas a similar extent of clay dispersion was seen using either premix or sequential feeding [ 18 ]. A further complexity may be added by the probable thermally-induced degradation of the polymer and/or clay material during many of the experiments reported in the literature, eventually polluting the results presented.…”

Decoupling the effects of screw speed and particle surface functionality on the filler suspension state in PBS/fumed silica nanocomposites

“…On the other hand, an increase in screw speed leads to higher shear rate and thus breakup of larger aggregates and improved dispersion. This effect has been widely observed on various nanocomposite systems . Moreover, this improved filler dispersion resulting from high shear rate can enhance rheological and mechanical properties .…”

“…This effect has been widely observed on various nanocomposite systems . Moreover, this improved filler dispersion resulting from high shear rate can enhance rheological and mechanical properties . These results can be explained by the theory that dispersion of filler agglomerates is achieved when the cohesive forces of the agglomerates are exceeded by the shear forces applied by the fluid flow …”

“…10,[17][18][19][20] Moreover, this improved filler dispersion resulting from high shear rate can enhance rheological and mechanical properties. [20][21][22] These results can be explained by the theory that dispersion of filler agglomerates is achieved when the cohesive forces of the agglomerates are exceeded by the shear forces applied by the fluid flow. [23][24][25][26] Conventional twin-screw extrusion of polymers reaches rotation speeds of up to 400 rpm, with a few research instruments capable of 1000 rpm.…”