Evaluation of specific total work of fracture in polypropylene/ethylene‐propylene diene monomer nanocomposites based on various graphene derivatives: Optimization by response surface methodology technique and correlation with microstructure properties

Abstract

This study presents an experimental design approach for optimization and prediction of specific total work of fracture (w f ) in polypropylene/ethylenepropylene diene monomer (EPDM) nanocomposites based on disparate graphene derivatives including multilayer graphene, few-layer graphene and graphene oxide. Box-Behnken design and response surface methodology (RSM) were exploited at three levels and four factors to construct a predictive mathematical model for the value of w f . The model predicted that the maximum value of w f (136.7 J/mm 2 ) is achieved by applying dynamically vulcanized system at EPDM content and few-layer graphene content of 20 wt% and of 0.5 wt%, respectively. In addition, by observing the fracture surfaces of specimens, a direct correlation between RSM predictions and morphology of nanocomposites was established. In this regard, transmission electron microscopy and wide-angle X-ray diffraction analyses showed that by using few-layer graphene, thanks to formation of an exfoliated structure, more energy for the failure of nanocomposites is required which substantiates the model predictions. Scanning electron microscopy observations depicted that the droplets diameter of homogeneous EPDM particle size plays a pivotal role in number of microvoids and nano-voids, which consequently promotes the creation of fibril structure and eventually heightens nanocomposite resistance against the applied load. The optimum status of this phenomenon happens at 20 wt% of EPDM and as the model showed, the value of w f reaches the highest point at this EPDM content. Likewise, by applying dynamic vulcanization, as truly predicted by the model, the formation of multi fibrillar structure led to dissipation of extra energy in nanocomposites inducing a remarkable improvement in the value of w f .

Mechanical behavior and essential work of fracture of surface‐modified exfoliated graphite filled polypropylene/ethylene‐vinyl acetate blend nano‐composites

“…Debonding and cavitation of droplets are mechanisms that ease fibrillation and shear banding of PP. 66 The nucleation of micro-holes in the ligament region reduces the stress concentration in these regions and activates the shear yielding of the matrix material. 5 The plastic growth of micro-holes in the direction of applying load reduces stress and accelerates shear yielding in the matrix.…”

Graphene in rubber formulations: a comprehensive review and performance optimization insights

“…Response surface methodology (RSM) is a mathematical and statistical technique that is commonly used for the optimization of graphene nanocomposites in rubber formulations. 23,24 RSM is preferred over traditional one-factor-at-a-time (OFAT) methods as it is more time and cost-efficient. 25,26…”

In situ emulsion polymerization of poly (vinyl acetate) and asparagus racemosus biopolymer composites for flexible energy storage applications

“…PMCs are multi-phase materials in which an organic or inorganic component is embedded within the polymer matrix in order to achieve interesting features not demonstrated by either component alone. [1][2][3] The attributes of polymer composites are generally determined by the properties of constituents, the filler volume fraction and the dispersion of filler within the polymer matrix. Thus, the final properties of PMCs can be tailored by properly selecting the individual components, which usually have different physical and chemical properties.…”