Morphological and rheological footprints corroborating optimum foam processability of PP/ethylene acrylic elastomer blend

Abstract

The focus of the present work is optimization of microcellular foam processing of Polypropylene (PP)/ethylene acrylic elastomer blends, through design of experiment approach using Taguchi technique and establishing correlation among foamability, morphological, and rheological parameters of blends. PP and elastomer are melt blended in a twin screw extruder and thereafter foaming parameter optimization is carried out using Taguchi method followed by analysis of variance (ANOVA) for batch foaming setup. Scanning electron microscope reveals development of submicron elastomer domains, which increase with the elastomer content. Further, complex viscosity and van Grup-Palmen plots are found to have a vital role in attaining cellular morphology development in blends. From Taguchi and ANOVA analysis it is established that foaming temperature has a great influence and major contribution on foamability. Blends with low elastomer content are optimized for better foamability using statistical approach and proved to be consistent with the morphological and rheological outcomes.

Correlation of Micro- and Macrostructural Attributes with the Foamability of Modified Polypropylene Using Supercritical CO2

“…The insignificant change in the density of foams with the change in the foaming temperature might be attributed to the compensation for the drop in the gas solubility with the drop in the viscosity of the polymer. The foam densities of PPIC1 and PPIC2 were similar to the foam densities of PP/ethylene acrylate thermoplastic vulcanizate (TPV) (80:20), which foamed at a foaming temperature of 150 °C and a saturation pressure of 75 bar . Extruded PP foams produced with a die temperature of 160 °C and 5 wt % CO 2 also had similar foam densities as PPIC1 and PPIC2, whereas the foam densities achieved for PPHP and PPRC were almost similar to the foam densities of the iPP nanocomposite, which foamed at a temperature of 157 °C, a saturation pressure of 85 bar, a saturation time of 6 h, and depressurization of 5 bar/s .…”

“…The foam densities of PPIC1 and PPIC2 were similar to the foam densities of PP/ ethylene acrylate thermoplastic vulcanizate (TPV) (80:20), which foamed at a foaming temperature of 150 °C and a saturation pressure of 75 bar. 33 Extruded PP foams produced with a die temperature of 160 °C and 5 wt % CO 2 also had similar foam densities as PPIC1 and PPIC2, 34 whereas the foam densities achieved for PPHP and PPRC were almost similar to the foam densities of the iPP nanocomposite, which foamed at a temperature of 157 °C, a saturation pressure of 85 bar, a saturation time of 6 h, and depressurization of 5 bar/s. 35 In general, the minimum foam densities achieved here are almost close to those of the extruded linear PP foams foamed using 5% butane as the blowing agent.…”

Improvement of the dispersity of micro‐nano particles for PP/PVC composites using gas‐assisted dispersion in a controlled foaming process

“…In addition, common linear PP has a very narrow window for appropriate foaming temperatures of only 2 C-4 C [26,27]. Blending with other polymers [28][29][30][31][32][33] and filling with micro-nano particles and fibers [27,[34][35][36][37] are effective methods for improving the foam structure and foaming behavior of PP since the different phases of the blend can decrease the gas bubble nucleation energy, and the incorporation of micro-nano fillers can provide more opportunities for heterogeneous nucleation. In this respect, blending PVC with PP can facilitate the formation of a fine cellular structure under appropriately controlled conditions.…”