Preparation and Characterization of Calcium Stearate Powders and Films Prepared by Precipitation and Langmuir−Blodgett Techniques

Abstract

The preparation of calcium stearate (CaSt 2 ) using precipitation and Langmuir-Blodgett techniques was investigated in this study. While sodium stearate and calcium chloride were used in the precipitation process, calcium stearate nanofilms were produced from stearic acid and calcium chloride in sodium borate buffer with the Langmuir-Blodgett technique. Fourier transform infrared (FTIR) spectroscopy indicated carboxylate bands at 1577 and 1543 cm -1 in equal intensity in the powder form, but the films had a higher intensity 1577 cm -1 band than the 1543 cm -1 band. This showed the calcium ions associated with the COO -ions in the monodendate and bidendate structures in powders, and it was mainly in the bidendate structure in films. While characteristic peaks of CaSt 2 at 2θ values of 6.40°and 19.58°were obtained in the X-ray diffraction (XRD) pattern of the dried powdered product, no sharp peaks were present in the 13 layer CaSt 2 film. From scanning electron microscopy (SEM) micrographs, it was seen that calcium stearate powder had lamellar structure and the average particle size was 600 nm. The AFM picture of the CaSt 2 film indicated the surface was not smooth with a peak to valley distance of 6 nm.

Hydrophobic Calcium Carbonate for Cement Surface

“…The antisymmetric and symmetric methylene stretching were observed at 2916 and 2849 cm −1 respectively. These results are in agreement with functional groups present for calcium stearate [27]. The IR results showed that the intensity of CH 2 stretching band increased initially for the temperatures from 30 to 90 • C and then decreased with further increase in temperature.…”

“…Besides the peaks of SiO 2 and CaCO 3 , few peaks at higher carbonation temperatures (60 and 90 • C) arise, which may be attributed to the association of organic molecule with the cement matrix to form calcium stearate. Ozturk et al have reported the synthesis and X-ray diffraction of calcium stearate [27]. As per the synthesis procedure we synthesized 50% excess calcium stearate precipitate and obtained XRD spectrum which showed a high intensity diffraction peak at 2θ value of 19.96 • .…”

Facile and eco‐friendly fabrication of hierarchical superhydrophobic coating from eggshell biowaste

“…1 The spectrum of stearic acid (C 17 H 35 COOH) exhibited absorption bands assigned to vibration of alkyl (-CH 3 and -CH 2 ) and carboxyl (-COOH) groups at 715/cm for C-H rocking, 2844 and 2910/ cm for C-H symmetric stretching, 940 and 1465/cm for C-O bending, and 1694/cm for C=O stretching. 28,29 This observation was similar to previous report for functionalization of precipitated CaCO 3 with stearic acid. Moreover, the absorption bands of carboxylate group (COO − ) at 1400 and 1575/ cm for asymmetric and symmetric stretching vibrations were also observed indicating the formation of calcium stearate ((C 17 H 35 COO) 2 Ca) through the esterification between the carboxyl group of stearic acid and the hydroxyl group of absorbed water on the eggshell surface.…”

“…14,26,28 It should be noted that there is an increase in the intensity of the band centered at 1400/cm after the surface modification caused by homogenization between the C=O and C-O bonds in the COO − group and association of the COO − group with calcium ions (Ca 2+ ) to form the calcium stearate phase. 28,29 This observation was similar to previous report for functionalization of precipitated CaCO 3 with stearic acid. 30 The FT-IR spectrum of coating layer consisting of stearic acid-modified eggshell/PS composites showed the absorption bands related to vibration of stearic acid-modified eggshell together with those related to the phenyl group of PS (C 8 H 8 ) n binder at 698/cm for aromatic C-H bending, 1455 and 1494/cm for aromatic C=C stretching, and 3030/cm for aromatic C-H stretching.…”

Structural Changes Undergone During Thermal Aging and/or Processing of Unstabilized, Dry-blend and Rigid PVC, Investigated by FTIR-ATR and Curve Fitting

“…The characteristic peak of CaSt2 at 1576 cm -1 was initially observed in the stabilizer system and dryblend spectra (Figure 3 and 7). This band in the u-PVC after curve-fitting appears more developed comparatively to the two other products and was assigned to the (as COO) [22,41]. A new peak appeared at 1544 cm -1 , attributed to the intermediate product, lead chloridostearate, (Pb(C17H35COO)Cl), generated by PbSt2 that neutralized HCl released from the PVC chains Eq.…”