Polypropylene/Graphene Nanocomposites: Effects of GNP Loading and Compatibilizers on the Mechanical and Thermal Properties

Abstract

In this research work, graphene nanoplatelets (GNP) were selected as alternative reinforcing nanofillers to enhance the properties of polypropylene (PP) using different compatibilizers called polypropylene grafted maleic anhydride (PP-g-MA) and ethylene-octene elastomer grafted maleic anhydride (POE-g-MA). A twin screw extruder was used to compound PP, GNP, and either the PP-g-MA or POE-g-MA compatibilizer. The effect of GNP loading on mechanical and thermal properties of neat PP was investigated. Furthermore, the influence and performance of different compatibilizers on the final properties, such as mechanical and thermal, were discussed and reported. Tensile, flexural, impact, melting temperature, crystallization temperature, and thermal stability were evaluated by using a universal testing system, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). For mechanical properties, it was found that increasing GNP content from 1 wt.% to 5 wt.% increased tensile strength of the neat PP up to 4 MPa. The influence of compatibilizers on the mechanical properties had been discussed and reported. For instance, the addition of PP-g-MA compatibilizer improved tensile strength of neat PP with GNP loading. However, the addition of compatibilizer POE-g-MA slightly decreased the tensile strength of neat PP. A similar trend of behavior was observed for flexural strength. For thermal properties, it was found that both GNP loading and compatibilizers have no significant influence on both crystallization and melting temperature of neat PP. For thermal stability, however, it was found that increasing the GNP loading had a significant influence on improving the thermal behavior of neat PP. Furthermore, the addition of compatibilizers into the PP/GNP nanocomposite had slightly improved the thermal stability of neat PP.

Mechanical Behavior of Melt-Mixed 3D Hierarchical Graphene/Polypropylene Nanocomposites

“…The resulting Young’s moduli, stresses at break and strain at break are shown in Figure 7 b–d. This can be associated with the extent of the network formation and is in qualitative agreement with previously reported results on similar materials [ 18 , 19 , 25 , 55 , 67 , 68 , 69 , 70 ]. From these findings, we can see a 30% increase in the modulus below the percolation threshold (~1 wt.%) [ 27 ], whereas the average increase above the electrical percolation threshold is a more moderate 15%.…”

Structure and Mechanical Properties of High-Density Polyethylene Composites Reinforced with Glassy Carbon

“…Moreover, literature reports [ 13 ] an increase in melt viscosity with the addition of higher amounts of graphene nanoplatelets. The addition of nanometric carbon reinforcement in polypropylene impedes crystallization of β-modification while simultaneously increasing the crystallinity of the polymer because of the higher amount of α-modification [ 11 , 13 , 14 ]. Combined, these effects lead to a slightly higher strength nanocomposite with a highly limited elastic deformation of the material [ 15 ].…”

Statistical Study on the Interaction Factors of Polypropylene-Graft-Maleic Anhydride (PP-g-MA) with Graphene Nanoplatelet (GNP) at Various Poly(Lactic Acid)/Polypropylene (PLA/PP) Blends Ratio

“…At a high ratio of PLA in the blends, PP-g-MA and GNP addition causes a gradual increase in tensile stress up to 50.06 MPa. The compatibilized PP/GNP with PP-g-MA shows better in [40].…”