Toughness of HDPE/CaCO₃ microcomposites prepared from masterbatch by melt blend method

Abstract

In this study, a series of high-density polyethylene and micro/nanocalcium carbonate polymer composites (HDPE/CaCO 3 nanocomposites) were prepared via melt blend technique using a twin screw extruder. Nanocomposite samples were prepared via injection molding for further testing. The effect of % loading of CaCO 3 on mechanical and fracture toughness of these composites has been investigated in details. The effect of precrack length variation on the fracture toughness of the composite samples was evaluated, and the morphology of the fractured samples was also observed using scanning electron microscopy (SEM). It was found that increasing the % of CaCO 3 and precrack length decreased the fracture toughness. Fracture surface examination by SEM indicated that the diminished fracture properties in the composites were caused by the aglomerization of CaCO 3 particles which acted as stress concentrators. A finite element analysis using ANSYS was also carried out to understand the effect of agglomeration size, interaction between the particles and crack tip length on the fracture properties of these composites. Finally, a schematic presentation of the envisioned fracture processes was proposed.

Processing and Characterization of High Density Polyethylene/Ethylene Vinyl Acetate Blends with Different VA Contents

“…Microscopic investigation of the fracture surfaces of neat HDPE and the blend samples with a precrack revealed a completely different morphology and fracture mechanism than that of the tensile sample. Ali and Elleithy [25] proposed a precracked fracture mechanism as illustrated in Figure 2. The surface of a fractured sample with a precrack can be divided into three main zones: I, initial precrack zone; II, slow crack propagation zone; and IV, fast crack propagation zone.…”

“…In addition, the crack propagation zone could be further subdivided into three zones, namely, transition zone III (slow-to-fast propagation zone) and two skin zones V and VI. The slow crack propagation zone (II) has an elliptical shape that could be characterized by its length (L) and width (d) [25].…”

Investigation on improvement of thermal, mechanical, and barrier properties of lignin/poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) using inorganic nanoparticles as fillers

“…It was found in the literature [10,11,[32][33][34] that the addition of lignin and INPs could improve the mechanical properties of some polymer matrix, so the tensile strength test of the INPs/L/P composites was carried out to characterize the mechanical properties of the composites. Figure 5 showed the typical stress-strain curves, tensile strength, Young's modulus, and elongation at break for PHBH, L/P, and INPs/L/P composites.…”

Estudo da estabilidade térmica e propriedades mecânicas de nanocompósitos de poliamida 6,6 com nanofibras de celulose

“…Em paralelo a esse cenário, pesquisadores têm focado seus trabalhos no processamento de nanocompósitos, devido aos fortes efeitos de reforço a uma fração de volume baixo [5][6][7][8][9]. Na nanoescala surgem novos fenômenos que não aparecem na macroescala.…”