Stiffness-toughness balance in PP/EPDM/SiO₂ ternary blend-nanocomposites: The role of microstructural evolution

Abstract

The effect of microstructural evolution with hydrophilic-nanosilica (SiO2) concentration, ranging from 0 to 5 wt%, on mechanical properties and deformation micromechanisms of PP/EPDM/SiO2 (80/20/x) ternary blend-nanocomposites was investigated. Morphological observations revealed that, SiO2 nanoparticles tend to localize either around the dispersed EPDM particles or at the PP/EPDM interface, promoting the formation of three dimentional network-like EPDM/SiO2 composite structures dispersed in the PP matrix, especially at higher SiO2 loadings. This type of dispersion state was further confirmed by the rheological analysis. Synergistic toughening effect of soft EPDM particles and rigid SiO2 particles under Izod impact test was observed in these ternary systems, so that the materials with a better balance of stiffness/toughness were achieved. The results demonstrated that the extent of impact toughness increase is higher, where a large amount of the SiO2 nanoparticles surrounded the EPDM dispersed particles distributed in the PP matrix. This significant increase was attributed to the change in the size of stress concentration region and evolution of stress distribution throughout the material. The failure mechanisms were studied, and the underlying toughening micromechanisms were proposed.

Dynamic and static mechanical properties of PP/EVA blend nanocomposites: Effects of type of masterbatch preparation technique and nature of compatibilizer

“…Some of these studies have been composite-based ones in which copolymers or blends of PP with rubbery polymers have been developed and produced with different fillers. 1,2 The required hardness/strength of PP has been recovered and its drawing performance improves when PP/elastomer blends are used together with the fillers. In ternary nanocomposite systems containing elastomer and nanoclay, there is a clear relationship between the location/distribution of the nanoclay and the shape of the elastomer particles, and the morphology and mechanical properties of these systems.…”

Design of super‐tough and antibacterialPPR/nano‐ZnOcomposites based on the excellent dispersion ofZnOparticles

“…Some documents indicated that as a nucleating agent, the introduction of nanoparticles into PPR will cause heterogeneous nucleation of the matrix, which leads to an increase in crystallization temperature. 12,46 In this study, the Tc of PZ increased by 1 C when the nano-fillers were 8 phr. This phenomenon shows that heterogenous nucleation, which needs a higher temperature, was occurred in PZ.…”

“…Then, they were cooled to 0 C at a rate of 10 C min −1 , held about 5 min at current temperature, and reheated to 190 C at a heating rate of 10 C min −1 . The crystallinity of PPR (Xc) in the samples was estimated from the second heating cycle using the following equation: 12 Xc…”

“…Many researchers reported that the method of adding nano-fillers to PP phase could facilitate the increase of the rigidity of composites, resulting the balance of the stiffness and the toughness. [10][11][12][13] Hajibabazadeh et al 6,11,12 studied PP/EPDM/SiO 2 ternary blend-nanocomposites and showed that they have higher toughness and stiffness than those of their reference binary blends, indicating the synergistic effects of the soft rubbery and the rigid silica phases in activation of various toughening mechanisms in the PP matrix. In addition, the results also showed that the shear yielding of the PP matrix was one of the main toughening mechanisms of the ternary systems.…”

Polypropylene/ethylene propylene diene monomer/cellulose nanocrystal ternary blend nanocomposites: Effects of different parameters on mechanical, rheological, and thermal properties

“…[24,25] Despite unique properties provided by EPDM rubber phase, it reduces PP stiffness. For dealing with this drawback, the recent studies have shown that rigid nanofillers, such as nanosilica, [26,27] nanoclay (NC), [28,29] carbon black (CB), [30,31] carbon nanotubes (CNT), [32,33] graphene, [34,35] etc., can greatly increase mechanical properties of blends.…”