Mechanical, Thermal, and Morphological Properties of Graphene Nanoplatelet-Reinforced Polypropylene Nanocomposites: Effects of Nanofiller Thickness

Abstract

In this work, polypropylene (PP) and graphene nanoplatelet (GNPs) composites are routed through twin screw mixing and injection moulding. Two types of GNPs with a fixed size of 25 µm with surface areas ranging from 50–80 m2/g (H25, average thickness 15 nm) and 120–150 m2/g (M25, average thickness 6–8 nm) were blended with PP at loading rates of 1, 2, 3, 4, and 5 weight%. Mechanical properties such as tensile, flexural, and impact strengths and Young’s modulus (Ε) are determined. The X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), field emission scanning electron microscopy (FESEM), and polarised light microscopy (PLM) techniques are used to understand the crystallisation, thermal, dynamic mechanical, and structural behaviour of the prepared composites. The improvement of mechanical strength is observed with GNP loading for both grades. Decreasing the GNP thickness decreases the impact strength and on the other hand improves the tensile and flexural strengths and Young’s modulus. Maximum tensile (≈33 MPa) and flexural (≈58.81 MPa) strength is found for the composite carrying 5 wt% M25. However, maximum impact strength (0.197 J) is found for PP-5 wt% H25. XRD analysis confirms GNPs have an induction effect on PP’s β phase crystal structure. The PP-GNP composite exhibits better thermal stability based on determining the TD (degradation temperature), T10 (temperature at 10% weight loss), T50 (temperature at 50% weight loss), and TR (temperature at residual weight). Enhancement in melt (Tm) and crystallisation temperatures (Tc) is are observed due to a heterogeneous nucleation effect. The FESEM analysis concludes that the GNP thickness has a significant effect on the degree of dispersion and agglomeration. The smaller the thickness, the better is the dispersion and the lower is the agglomeration. Overall, the use of thinner GNPs is more advantageous in improving the polymer properties.

Experimental analysis with grey relational analysis–analytic hierarchy process‐based hybrid optimization to analyze the effect of graphene nanoparticle reinforced ultra‐high molecular weight polyethylene/n‐HAp for hip joint

“…As a result, the interfacial bonding between the filler‐matrix interface and the filler‐filler interface is weak in composites. [ 38,39 ] When stress is applied, the filler material is unable to transmit the stress to the matrix materials, resulting in fracture initiation. Increased stress on composite materials leads to increased fracture propagation and brittle failure.…”

Segregated highly conductive linear low‐density polyethylene/graphene nanoplatelet composite through aqueous dispersing and self‐leveling method

“…When the GN content was 1.0 wt%, the T 5% and T max of composites increased from 446.5 to 450.8°C and 480.5 to 486.5°C, respectively. The micro‐sized GN with nano‐thickness has a large diameter‐thickness ratio, which forms physical barrier effect that slows down thermal degradation 53 . In addition, the better dispersion of GN inside the polymer matrix as demonstrated by XRD, restricts the mobility of the LLDPE molecular and increases the energy required for thermal degradation 25 …”

Effect of multi‐walled carbon nanotube localization on toughening mechanism and electrical properties of compatibilized PP/EOC immiscible blend

“…), the amount and ability to interact with polymer matrix, and the possibility of forming a 3D structure. [16][17][18][19][20] Lu et al [21] investigated the toughening mechanisms of PP/CaCO 3 . They reported a sharp increase in the Izod notched impact strength by increasing CaCO 3 content.…”