The influence of screw configurations and feed mode on the dispersion of organoclay on PP

Abstract

The design of the screw configuration as well as the screw speed, the residence time, the feeder type, and the temperature has a large effect on the dispersion of the clay into the matrix and, consequently, on the mechanical and thermal properties of the polymeric matrix. The objective of the present work was to evaluate the influence of two different screw configurations (left-handed elements) and the feed type (hopper or side feeder) on the dispersion of 5 wt% Cloisite 20A into the PP matrix without the use of compatibilising agents. In profile 1 (lower shear), the 5 wt% C20A/PP (PPC20AP1) nanocomposite morphology presented elliptical agglomerated structures with compacted platelets, whereas in the profile 2, the 5 wt% C20A/PP (PPC20AP2) showed elongated forms with better separated platelets and a better clay distribution into the PP matrix. When the side feeder mode was used in profile 2, a mix of elliptical and elongated structures with some individual clay sheets was observed.The neat PP showed the same tensile modulus and impact strength in both screw configurations. The PPC20AP1 presented a tensile modulus and an impact strength that was lower than the PPC20AP2, because in profile 2 the pressure and residence time are higher due to the two left-handed elements. Thus, the dispersion and distribution of the clay throughout the matrix were improved, and the agglomerated structures were reduced. When the side feeder mode was used, there was a decrease in the PP/clay mechanical properties, but the values found were higher than those in profile 1.

Nanocomposite of polypropylene/octadecylamine lamellar-zirconium phosphate: Influence of nanofiller and screw speed

“…Mauler and co-workers 32 and Modesti et al. 33 pointed out that thermal stability of PP matrix was improved independent on the profile screw configuration and feeder type for PP/organoclay nanocomposite.…”

“…About crystallinity degree (X c ), only the nanocomposite processed at 90 r/min showed some decreasing. Mauler and his co-workers 32 reported that different screw configurations and feed modes did not affected T m but the presence of organoclay promotes a slight increasing on T c and decreasing of PP degree of crystallinity. Modesti et al .…”

Nano lamellar zirconium phosphate and screw speed changing properties of melt extrusion polypropylene nanocomposites

“…Modesti et al 46 reported an increase of PP degree of crystallinity in composites filled with montmorillonite. Santos et al 47 registered no variation of T m and X c in their work on the influence of screw configurations and feed mode on the dispersion of organoclay into PP matrix. We devote our results as nucleation effect of the zirconium phosphate through the transcrystallization (heterogeneous nucleation on the highly crystalline matter).…”

Effect of CaO Nanoparticles on the Properties of Polyamide 6

“…The amide groups of polyamide are very polar, and hydrogen bonds can form between them. Because of these, and because the polyamide backbone is so regular and symmetrical, polyamides are often crystalline, and make very good fibers (15)(16) . Mixing and dispersing nanosized particles in polymer matrices provide the resulting materials with a variety of properties which are simply not available for bulk composites with high filler loading.…”