Effect of Feeding Strategy on the Mechanical Properties of PP/Recycled EPDM/PP-G-MA Blends

Abstract

In this work, thermoplastic elastomers based on polypropylene (PP) and recycled ethylene-propylene-diene monomer (r-EPDM) blends with polypropylene-graft-maleic anhydride (PP-g-MA) as modifier (0 to 8wt.%) were prepared by melt compounding via twin-screw extrusion followed by injection molding. In particular, the effects of material composition and feeding strategies were studied. The morphological and mechanical properties of the blends were investigated by using scanning electron microscopy (SEM), tensile, flexural, impact, density and hardness tests. The results indicate that good dispersion and compatibility between PP and r-EPDM particles was obtained and that incorporation of r-EPDM leads to significant increase in PP impact strength. Finally, the feeding order of each component in the extruder was found to modify substantially the final morphology of the blend, thus having ad irect influence on their mechanical properties.

Ground tire rubber/polyamide 6 thermoplastic elastomers produced by dry blending and compression molding

“…These TPE can have significant increases (up to 143 J/m) even if both individual materials (PA6 and GTR) have similar impact strengths in the range of *60 J/m. This positive trend has been reported for composites based on rubber particles and PA6, 39 PP, 19 and PS. 45…”

Ground tire rubber/polyamide 6 thermoplastic elastomers produced by dry blending and compression molding

“…These TPE can have significant increases (up to 143 J/m) even if both individual materials (PA6 and GTR) have similar impact strengths in the range of *60 J/m. This positive trend has been reported for composites based on rubber particles and PA6, 39 PP, 19 and PS. 45…”

Phase morphology, mechanical, and thermal properties of fiber-reinforced thermoplastic elastomer: Effects of blend composition and compatibilization

“…49 Despite the negative effect of filler content on toughness loss, further increase in recycled rubber content from 35 to 65 and 80 wt.% increased the toughness of R65 (272.5 J/m) and R80 (324.4 J/m) because of higher energy absorption through deformation of the rubbery particles retarding fracture phenomena. 50 In agreement with Figure 8, Luna et al 51 reported toughness improvement in polystyrene (PS) composites by up to 77% with increasing recycled SBR content from 20 wt.% (37.5 J/ m) to 50 wt.% (66.5 J/m). For rHDPE/RR/RTF blends, replacing the rubber phase with constant RTF content (20 wt.%) decreased the toughness of fiber-reinforced specimens as the impact strength of R45F and R60F are, respectively, 9% and 11% lower than R65 and R80, both having 65 and 80 wt.% of fillers.…”

Effect of Feeding Strategy on the Properties of PP/Recycled EPDM Blends

“…Also, the feeding sequence during polymer blending has significant influence due to the dependence of final blend properties on the mixing quality achieved in the extruder. As reported in our previous study (Mahallati and Rodrigue, 2014) and also shown here, feeding the r-EPDM first not only produces smaller particles, but also better interaction with the matrix as possible thermo-mechanical regeneration of the crosslinked rubber can occur (Macsiniuc et al, 2010;2012). This gives more freedom for the rubber molecules on the surface of the particles to entangle with the macromolecular chains of the matrix and improve dispersion/stress transfer.…”

“…were studied for af ixed r-EPDM content of 50 %wt. (Mahallati and Rodrigue, 2014). From this work, it was found that coupling agent addition is not necessary for this optimized system (processing conditions).…”

Ground tire rubber/polyamide 6 thermoplastic elastomers produced by dry blending and compression molding

“…These TPE can have significant increases (up to 143 J/m) even if both individual materials (PA6 and GTR) have similar impact strengths in the range of *60 J/m. This positive trend has been reported for composites based on rubber particles and PA6, 39 PP, 19 and PS. 45…”

Phase morphology, mechanical, and thermal properties of fiber-reinforced thermoplastic elastomer: Effects of blend composition and compatibilization

“…49 Despite the negative effect of filler content on toughness loss, further increase in recycled rubber content from 35 to 65 and 80 wt.% increased the toughness of R65 (272.5 J/m) and R80 (324.4 J/m) because of higher energy absorption through deformation of the rubbery particles retarding fracture phenomena. 50 In agreement with Figure 8, Luna et al 51 reported toughness improvement in polystyrene (PS) composites by up to 77% with increasing recycled SBR content from 20 wt.% (37.5 J/ m) to 50 wt.% (66.5 J/m). For rHDPE/RR/RTF blends, replacing the rubber phase with constant RTF content (20 wt.%) decreased the toughness of fiber-reinforced specimens as the impact strength of R45F and R60F are, respectively, 9% and 11% lower than R65 and R80, both having 65 and 80 wt.% of fillers.…”

Effect of Feeding Strategy on the Properties of PP/Recycled EPDM Blends

“…Also, the feeding sequence during polymer blending has significant influence due to the dependence of final blend properties on the mixing quality achieved in the extruder. As reported in our previous study (Mahallati and Rodrigue, 2014) and also shown here, feeding the r-EPDM first not only produces smaller particles, but also better interaction with the matrix as possible thermo-mechanical regeneration of the crosslinked rubber can occur (Macsiniuc et al, 2010;2012). This gives more freedom for the rubber molecules on the surface of the particles to entangle with the macromolecular chains of the matrix and improve dispersion/stress transfer.…”

“…were studied for af ixed r-EPDM content of 50 %wt. (Mahallati and Rodrigue, 2014). From this work, it was found that coupling agent addition is not necessary for this optimized system (processing conditions).…”

Ground tire rubber/polyamide 6 thermoplastic elastomers produced by dry blending and compression molding

“…These TPE can have significant increases (up to 143 J/m) even if both individual materials (PA6 and GTR) have similar impact strengths in the range of *60 J/m. This positive trend has been reported for composites based on rubber particles and PA6, 39 PP, 19 and PS. 45…”

Phase morphology, mechanical, and thermal properties of fiber-reinforced thermoplastic elastomer: Effects of blend composition and compatibilization

“…49 Despite the negative effect of filler content on toughness loss, further increase in recycled rubber content from 35 to 65 and 80 wt.% increased the toughness of R65 (272.5 J/m) and R80 (324.4 J/m) because of higher energy absorption through deformation of the rubbery particles retarding fracture phenomena. 50 In agreement with Figure 8, Luna et al 51 reported toughness improvement in polystyrene (PS) composites by up to 77% with increasing recycled SBR content from 20 wt.% (37.5 J/ m) to 50 wt.% (66.5 J/m). For rHDPE/RR/RTF blends, replacing the rubber phase with constant RTF content (20 wt.%) decreased the toughness of fiber-reinforced specimens as the impact strength of R45F and R60F are, respectively, 9% and 11% lower than R65 and R80, both having 65 and 80 wt.% of fillers.…”

Effect of Feeding Strategy on the Properties of PP/Recycled EPDM Blends

“…Also, the feeding sequence during polymer blending has significant influence due to the dependence of final blend properties on the mixing quality achieved in the extruder. As reported in our previous study (Mahallati and Rodrigue, 2014) and also shown here, feeding the r-EPDM first not only produces smaller particles, but also better interaction with the matrix as possible thermo-mechanical regeneration of the crosslinked rubber can occur (Macsiniuc et al, 2010;2012). This gives more freedom for the rubber molecules on the surface of the particles to entangle with the macromolecular chains of the matrix and improve dispersion/stress transfer.…”

“…were studied for af ixed r-EPDM content of 50 %wt. (Mahallati and Rodrigue, 2014). From this work, it was found that coupling agent addition is not necessary for this optimized system (processing conditions).…”