Mechanical behavior of CaCO₃ particulate‐filled β‐crystalline phase polypropylene composites

Abstract

β‐crystalline phase polypropylene (PP) composites containing 5, 10, 20, 30, and 40% (by weight) of CaCO3 filler were prepared by injection molding. The β‐form PP was produced by adding a bicomponent β‐nucleator consisting of equal amounts of pimelic acid and calcium stearate. The morphology, static tensile, and impact properties of these composites were investigated in this study. Scanning electron microscopy (SEM) observations revealed that the β‐spherulites of the polymer matrix of the composites exhibit curved lamellae and sheaf‐like structures. The fillers were observed to disperse within the inter‐lamellar spacings of the β‐PP composite containing 10% calcium carbonate addition. However, the filler particles tend to link together to form larger aggregates when the filler content reaches 20%. Static tensile measurements showed that the elastic modulus of the composites increases with increasing filler content but the yield strength decreases with increasing filler addition. The falling weight Charpy impact test indicated that the β‐PP polymer exhibits the highest critical strain energy release rate (Gc) value. However, there was a drastic drop in Gc of the β‐PP composites with increasing filler content. The results are discussed and explained in terms of materials morphology.

Influence of the beta crystalline phase fraction on the mechanical behavior of polypropylene/calcium carbonate/polypropylene - graft - maleic anhydride composites

“…Calcium carbonate is among the most common particulate filler added to iPP in order to reduce its cost and improve its rigidity, although reduction of ductility and toughness is usually observed. Tjong et al [1] analyzed iPP composites having up to 40% of CaCO 3 and concluded that a drop in impact resistance and yield strength with increasing filler content is due to a decrease in the concentration of the tougher polymer matrix, an increase in the amount of the weaker filler/matrix interface, and to the debonding of the filler from the polymer matrix. Premphet & Horanont [2] demonstrated that up to 10% in volume of surface treated CaCO 3 , iPP composites may exhibit higher impact strength, however, concomitantly, a significant reduction in the tensile yield strength.…”

“…Premphet & Horanont [2] demonstrated that up to 10% in volume of surface treated CaCO 3 , iPP composites may exhibit higher impact strength, however, concomitantly, a significant reduction in the tensile yield strength. Many researchers [1][2][3][4][5][6][7] have studied the toughening of iPP with CaCO 3 , so the improvement of the impact strength followed by the reduction of yield strength, flexural strength and modulus of the composites are the ordinary outcome. It was also observed, that among different types of calcium carbonate particles, those which were surface treated and submicron sized gave composites with superior combination of mechanical properties [3][4][5][6][7] .…”

“…The technological interest on the beta phase, fraction and spherulites' size and morphology, relies on its strong influence on the mechanical properties of iPP, including higher impact resistance [1,[18][19][20][21]22] .…”

An investigation on physical properties of polyethylene composite with bentonite, kaolin and calcium carbonate additives

“…Calcium carbonate is used frequently in plastic sector. This material which is used to increase colour property and quality of dyeing is often seem in nature [10,11]. In this study, calcium carbonate, bentonite, and kaolin clay were mixed with Low Density Polyethylene (LDPE) material in certain mass ratio, and composite materials are made.…”

Mechanical and Thermal Properties of Polypropylene Reinforced by Calcined and Uncalcined Zeolite

“…As an example, high specific surface area of the fillers is expected to enhance interphase effects and tensile strength of the PP [1]. For this purpose, different types of reinforcing agents have been used, such as CaCO 3 [2], talc [3], mica [4], and glass fiber [5].…”