Effect of surface modification of calcium carbonate nanoparticles on their dispersion in the polypropylene matrix using stearic acid

Abstract

In this study, effects of surface modification of calcium carbonate (CaCO3) nanoparticles with a single-layer of stearic acid were investigated on dispersion in polypropylene (PP) matrix. Two kinds of CaCO3 nanoparticles (monolayer-coated and uncoated) were used to investigate this effect. All combinations were mixed in a co-rotating twin screw extruder and then were injection molded. After breaking the injection molded parts in liquid nitrogen, effect of surface modification of nanoparticles on their dispersion in the PP matrix was investigated using a field emission scanning electron microscope (FESEM). The results showed good agreement between the measurements made with the TGA analysis and the existing theories. The surface modification of calcium carbonate nanoparticles using a single layer of stearic acid also had an effective influence on improving distribution and dispersion of nanoparticles in the PP matrix.

Mechanical and rheological properties of polypropylene/bentonite composites with stearic acid as an interface modifier

“…However, the compounds with modified bentonite and stearic acid in the hopper of the extruder showed the best dispersion state (Figure 4). 23 The extra addition of this fatty acid as an additive to the formulation improved the interactions between the polymer and the filler even more because of interfacial modifications. This means that the surface treatment with stearic acid significantly reduced the filler surface free energy and particle-particle interaction; this led to better dispersion of the particles in the polymer matrix and reduced the filler agglomerates.…”

Comparison of the effect of reactive and nonreactive treatments on the dispersion characteristics of a calcium carbonate (calcite) filler in a polypropylene matrix composite

“…Calcium carbonate or calcite (CaCO 3 ) is one of the most favorite fillers used in polymer composites owing to its low cost, availability, easy manufacturing, whiteness, reinforcing properties, and contribution to improvements in mechanical properties such as strength, modulus, and toughness. [3][4][5][6][7][8] Calcite is an important rock-forming mineral in sedimentary environments. It is mined and ground to micron-sized particles and is called ground calcium carbonate (GCC).…”

“…[9] The incompatibility between the hydrophilic, polar, high-energy surfaces of the calcite grains and hydrophobic, nonpolar, low energy polymer surfaces is a problem that must be solved prior to compound production. [3,10,11] Fine-grained calcite grains tend to agglomerate owing to their high surface area and high surface energy. In addition, the risk of agglomeration increases further, as they are added to composites at high rates owing to the above-mentioned positive contributions of calcite to the composite.…”

“…[15] In the literature, the properties of the surface modified CaCO 3 in powder form have been analyzed by various techniques such as brunauer-emmett-teller method (BET), fourier transform Infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). [3,4,16] However, while these analyzes provide information on surface energy and hydrophobicity of CaCO 3 particles, these properties cannot fully explain the quality of the dispersion in a thermoplastic polymer matrix. The authors think that tests that can measure the behavior and dispersion of the surface-modified calcium carbonate in the thermoplastic polymer will yield clearer results.…”

“…The effect of surface modification of calcium carbonate on dispersions of thermoplastic polymer composites was tested in previous studies mostly by morphological and mechanical analysis. [3,4,[16][17][18][19] The study where the rheological behavior is measured for this purpose on the surface-modified CaCO 3 /PP composites is limited. [20,21] Since the screen pack analysis or filter test is usually applied in pigments, no study has been found by the authors including filter test demonstrating the effect of surface modification on dispersion of CaCO 3 in CaCO 3 /PP composites.…”