Incorporation Of Calcium Carbonate Research Articles

UV- shielding and antioxidant properties of chitosan film impregnated with Acacia catechu modified with calcium carbonate for food packaging

Acacia catechu contains polyphenolic compounds such as catechin and tannins, which exhibit antioxidant and antimicrobial properties that have the potential to be used in food packaging applications. In this study, chitosan-based (CH) antioxidant films were developed with the incorporation of calcium carbonate (CC) and Acacia catechu (CT). The films were fabricated by the solvent-casting method, and the effects of the different concentrations of Acacia catechu were analyzed. The physicomechanical, antioxidant, and UV shielding properties of the films were determined. The addition of Acacia catechu and calcium carbonate has significantly increased the tensile from 2.30 MPa to 4.95 MPa, respectively, for neat CH and CH/CC/CT-4 film. At the same time, there is a reduction in the elongation at break from 26.75 % in neat CH film to 12.11 % in CH/CC/CT-4 film. The CH/CC/CT-4 film has shown the highest ferric-reducing antioxidant power (FRAP) of 0.440 mg Trolox/g dried weight of the film and 2,2 diphenyl picrylhydrazyl (DPPH) radical scavenging activity of 93.05 %. The UV transmittance of CH/CC/CT-4 film was 0.46 %, the lowest compared to the rest of the fabricated films. These active properties depict that CH/CC/CT-4 film has the potential to be utilized for the packaging of light and oxygen-sensitive food products.

Influence of calcium carbonate on green self-compacting concrete incorporating porcelain tile waste as coarse aggregate replacement

The disposal of ceramic tile waste poses a significant environmental challenge in the construction industry. This study aims to explore the influence of calcium carbonate (CC) on the properties of self-compacting concrete (SCC) incorporating porcelain tile waste as a coarse aggregate replacement. The objective is to enhance the performance of SCC while addressing the limitations of recycled ceramic aggregates and achieving the desired strength class. SCC specimens were cast by partially and completely substituting natural crushed rock with varying percentages of porcelain tile aggregates (PTA-0, 25 %, 50 %, 75 %, and 100 %) and cement with calcium carbonate (CC-10 %, 20 %, and 30 %). Workability assessments, mechanical properties, and durability were evaluated and compared against those of reference concrete. The experimental findings revealed that the incorporation of CC and PTA positively influenced the workability, mechanical properties and durability of SCC. Notably, the SCC mixture incorporating 10 %CC and 25 %PTA demonstrated exceptional performance, achieving the highest compressive strength of 64.9 MPa at 28 days. Moreover, even with complete substitution, the compressive strength reduction remained below 5 %. These results highlight the potential of PTA and CC-based SCC mixtures as an efficient and sustainable approach for utilizing porcelain tile waste in high performance concrete production. The findings contribute to addressing environmental concerns, promoting waste management practices, and reducing the reliance on natural resources in the construction industry.

Characterization of CaCO3 Filled Poly(lactic) Acid and Bio Polyethylene Materials for Building Applications.

Noise pollution has been identified as a cause of a broad spectrum of diseases, motivating researchers to identify building materials capable of attenuating this pollution. The most common solution is the use of gypsum boards, which show a good response for low frequencies but have a poorer response for high frequencies. In addition, due to environmental concerns associated with buildings, the use of materials that minimize environmental impacts must be favored. In this research, two biopolymers, a poly(lactic) acid and a bio-polyethylene, were filled with two typologies of calcium carbonate, and their soundproofing properties were tested using impedance tubes. In addition, the morphology of the fillers was characterized, and here we discuss its impact on the mechanical properties of the composites. The results showed that the incorporation of calcium carbonate into bio-based thermoplastic materials can represent a strong alternative to gypsum, because their mechanical properties and sound barrier performance are superior. In addition, the inclusion of mineral fillers in thermoplastic materials has a positive impact on production costs, in addition to preserving the advantages of thermoplastics in terms of processing and recycling. Although the use of carbonate calcium decreases the mechanical properties of the materials, it enables the production of materials with insulation that is four-fold higher than that of gypsum. This demonstrates the potential of these materials as building lightweight solutions.

Effect of Calcium Carbonate on the Mechanical Properties and Microstructure of Red Clay

The influence of precipitated calcium carbonate on the strength and microstructure of red clay was studied. Precipitated calcium carbonate was added to red clay at ratios of 0%, 5%, 10%, 15%, and 20%. Shear tests were carried out on the samples to observe the effect of calcium carbonate on the mechanical properties of red clay. The results showed that, with increasing calcium carbonate content, the strength of red clay first decreased and then increased. The maximum strength was obtained for the sample with 20% calcium carbonate. Scanning electron microscopy (SEM) was used to observe the changes in microstructure caused by addition of calcium carbonate. The pores and cracks analysis system (PCAS) was used to quantitatively characterize the microstructure changes detected in SEM images. The addition of calcium carbonate decreased the pore area and increased the total number of pores of red clay. The incorporation of calcium carbonate caused the red clay particles to agglomerate. The higher the calcium carbonate content, the stronger the agglomeration of red clay particles in the soil samples.

Improving the mechanical and thermal properties of chlorinated poly(vinylchloride) by incorporating modified CaCO3nanoparticles as a filler

Chlorinated poly(vinyl chloride) (CPVC)/calcium carbonate nanocomposites were successfully prepared by the incorporation of calcium carbonate (CaCO3) nanoparticles into the CPVC matrix. The compatibility between the two phases was obtained by surface modification of the CaCO3 nanoparticles with stearic acid, leading to improved material performance. The effects of the addition of different amounts of CaCO3 nanoparticles to the CPVC on the thermal, mechanical, and morphological characteristics of the CPVC/CaCO3 nanocomposites were investigated. The thermal stability of the CPVC/CaCO3 nanocomposites was evaluated by thermogravimetric analysis and differential scanning calorimetry. In addition, the surface texture of the CPVC and the dispersion of the CaCO3 were evaluated using scanning electron microscopy. Important enhancements in the thermal and mechanical properties of the modified CPVC/CaCO3 nanocomposites were obtained by incorporating different amounts (2.00%, 3.75%, and 5.75%) of surfacemodified CaCO3 nanoparticles within the CPVC polymer matrix. The results reveal that 3.75% of CaCO3 was the optimum amount, where the CPVC/CaCO3 nanocomposite shows the highest impact strength, the highest tensile strength, the highest thermal stability, and the lowest elongation percentage: Replacement of the commercial impact modifier used in industry with the prepared surface-modified CaCO3 nanoparticles for the development of CPVC was successfully achieved.

Preparation and characterization of red seaweed/calcium carbonate composite films

This study aims to evaluate the influence of inorganic filler on the properties of seaweed-based film. Seaweed composite films were prepared from raw red seaweed (Kappaphycus alvarezii) in the presence of glycerol with the incorporation of calcium carbonate (CaCO3). Solution casting technique was used to form films and dried at 40 ˚C in the ventilation oven for 24 hours. The effects of different CaCO3 concentrations [0.5%, 1.0%, 1.5%, 2.0% (wt. %)] on the physical, mechanical, and thermal properties were determined. Molecular interaction between the functional groups of red seaweed and CaCO3was examined through Fourier transform infrared spectroscopy (FTIR). The obtained result demonstrated that the addition of CaCO3 improved the neat seaweed film properties in terms of tensile strength, hydrophobicity, thermal properties and reduced the problem of brittleness encountered in seaweed-based film. However, excessive loading of CaCO3 had led to weaker film properties. Raw red seaweed and CaCO3 has shown compatibility through the analyses of FTIR, thermal, and mechanical of the composite films.

Physico-chemical and mechanical characterization of high volume fly ash incorporated and engineered cement system towards developing greener cement

High volume fly ash (HVFA) concretes are not gaining acceptance in construction industry because of low strength. The low strength of HVFA cement systems can be improved by suitable engineering of the mixes through incorporation of micro and nano materials. In the present study, hydration mechanism has been altered and engineered through incorporation of calcium carbonate (CC) obtained from various sources and efficacies of using CC have been examined through physico-chemical and mechanical characterization. Calcium carbonate obtained from egg shell and lime sludge (a paper industry waste) as well as commercially obtained micro- and nano-calcium carbonate are used in HVFA cement system to accelerate the hydration. It is found that the excess presence of silica from HVFA is utilized to develop hydration products by supplying calcium as an external source, to solve the perennial problem of reduction in strength due to HVFA in cement. Further, it is found that with the incorporation of nano (NC) and micro (LS) CC, it is possible to recover the loss in strength of 60% cement replacement upto 98% and 65% of the original matrix respectively. It is revealed from the hydration studies that the strength gained is not only dependent on the formation of calcium silicate hydrate (C-S-H) but depends also on the other hydration products such as carboaluminates. Moreover, net benefits of using HVFA envisaged that the calcium carbonate incorporated high volume fly ash would be qualifying as greener cement.

Pullulan based porous semi-IPN hydrogel: Synthesis, characterization and its application in the removal of mercury from aqueous solution

A pullulan-graft-polyacrylamide semi-IPN hydrogel was prepared by free radical polymerization and became porous by the incorporation of calcium carbonate and a subsequent acid treatment. The product was characterized by Fourier transform infrared spectroscopy, thermal gravimetric analysis, and optical microscopy to confirm the formation of porous hydrogels. In addition, the effect of several variables such as monomer, crosslinker, initiator and porogen concentration on swelling ratio and porosity of hydrogels was explored. The maximum porosity and swelling capacity in the optimized conditions were found to be 96.5% and 3089%, respectively. The prepared hydrogel was utilized as a selective adsorbent of Hg(II) ions from an aqueous solution with fast and high removal efficiency. The mercury sorption capacity under non-buffered conditions is achieved 8.6 mmol/g in the first 90 min via colorimetric method. The mechanism of adsorption was well presented using a pseudo-second-order kinetic model. Furthermore, the isothermal adsorption equilibrium data were fitted to Freundlich model. Finally, the mercury-loaded hydrogel was regenerated without losing its original activity and stability.

Engineered Bone-Inspired Multicomponent Bionanocomposite Scaffolds with Tunable Hardness and Modulus

ABSTRACTWe show a novel, bioengineered, moldable platform for bone regeneration composed of porous bionanocomposite scaffolds made of components that are normally found in bone tissue (calcium, collagen, carbonate, sodium, and phosphorous). To accommodate high- or low-stress environments, the hardness and modulus (stiffness) of these scaffolds can be tuned in a wide range in Megapascal (MPa) to Gigapascal (GPa) regions, while maintaining the required viscoelasticity. Our approach to control the mechanical properties is based on a new formulation of mineralized bioscaffolds by incorporation of calcium carbonate in which, calcium and phosphorous are in the form of calcite, calcium polyphosphate (CPP) and hydroxyapatite (HAP). The variation in the calcium carbonate concentration allows tuning of calcite/CPP contents in the bioscaffold to tailor the degree of mineralization and mechanical and viscoelastic properties that closely match those of natural bone. Our results demonstrate an ideal framework for new bone scaffold designs for advanced bone substitute applications.

Influence of Filler Types and Contents on Foaming Structures in ABS Microcellular Foams

The influence of filler types and concentration on the foaming structure was investigated using a batch method to penetrate CO2 in ABS polymer matrix. Vapor grown carbon fiber (VGCF®, averaged diameter = 150 nm), and calcium carbonate (averaged particle diameter = 1.8 μm) were used as fillers and the concentration was changed from 5 to 15 wt %, respectively. Vapor grown carbon fiber or calcium carbonate was compounded with ABS using an extruder and samples were made by hot press method. Foamed samples, whose density reduction showed about 30–40%, were made by controlling preparation conditions.In the case of vapor grown carbon fiber/ABS systems, the average diameter of foaming cell decreased, and the cell density increased as a function of fiber concentration. On the other hand, by the incorporation of calcium carbonate, the diameter increased, and density decreased with higher concentration. The initial nucleation stages of foaming from fillers were carefully observed for fillers having large aspect ratio and particle shape. Based on the evidences from optical microscope observation, the different tendency of cell diameter between the two systems as a function of concentration was discussed.

Fabrication and properties of poly(propylene carbonate)/calcium carbonate composites

AbstractComposites of poly(propylene carbonate) (PPC) reinforced with micrometric and nanometric calcium carbonate particles were prepared via melt mixing followed by compression molding. The morphology and mechanical and thermal behaviors of the composites were investigated. Static tensile tests showed that the tensile strength, stiffness, and ductility of the composites tended to increase with increasing contents of micrometric calcium carbonate particles. This improvement in the tensile properties was attributed to good interfacial adhesion between the fillers and matrix, as evidenced by scanning electron microscopy examination. However, because of the agglomeration of calcium carbonate nanoparticles during blending, those composites with nanoparticles exhibited the lowest tensile strength. Thermogravimetric measurements revealed that the incorporation of calcium carbonate into PPC resulted in a slight improvement in its thermooxidative stability. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1806–1813, 2003

Wet deposition and related atmospheric chemistry in the São Paulo metropolis, Brazil: Part 1. Major inorganic ions in rainwater as evaluated by capillary electrophoresis with contactless conductivity detection

The metropolitan region of São Paulo (17.8 million inhabitants) presents serious air quality problems. An official network monitors key air pollutants, however, there is no regular program of evaluation of the wet deposition and data about rainwater composition is scarce. Opening a series of articles on this subject, capillary zone electrophoresis with contactless conductivity detection (CZE-CCD) is proposed and applied as a quick and inexpensive alternative to ion chromatography for the determination of the ionic composition of rainwater. Excellent resolution of the peaks and sufficient sensitivity were obtained for major ions. Switching from anion to cation determination is fast (30 min) and as simple as inverting the polarity of the voltage supply and changing the modifier added to the buffer solution. CZE-CCD was applied to the study of wet-only deposition collected in São Paulo during the period from May l997 to March 1998. The volume weighted means of the anions, sulfate, nitrate and chloride, were, respectively, 17, 22 and 29 μmol l −1. Among the cations, ammonium was the dominating one, with 28 μmol l −1, followed by calcium, 23 μmol l −1, sodium, 12 μmol l −1, and potassium, 5.8 μmol l −1. The wet flux of these anions and cations were, respectively, 2.5, 2.2, 1.6, 0.78, 1.4, 0.43 and 0.35 g m −2 yr −1. By attributing all sodium to marine origin, half of the chloride and more than 90% of all other ions are ascribable to continental/anthropogenic sources. Literature data for rainwater from inland regions (∼200 km apart from São Paulo) reveals lower deposition of all ions but H +. Absorption of NH 3 and incorporation of calcium carbonate, mainly in the metropolitan region itself, accounts for decreased acidity. The enrichment in all other ions during the studied period indicates the prevalence of the anthropogenic emissions from the metropolis over continental sources and explains the high correlation between the ions NO 3 −, SO 4 2−, and NH 4 +; the same ions responsible for a factor that, alone, explains 42% of the variability in the PCA.

Polypropylene toughened with calcium carbonate mineral filler

A polypropylene homopolymer was modified by a rigid filler consisting of three different sizes of CaCO3 particles in various volume fractions. The materials were characterized by differential scanning calorimetry. Mechanical properties of extrusion blended/injection molded samples, including tensile, flexural, Dynatup impact energy and notched Izod impact energy, were examined as a function of temperature down to—40°C, filler particle size, and filler volume fraction.Dynatup impact tests were performed for compression molded plastic parts. The toughening mechanism of PP homopolymer through the incorporation of calcium carbonate depends on the filler particle size and volume fraction. The toughness of the CaCO3 filled materials increased significantly at ambient temperature for both material samples and molded plastic parts. A similar improvement was demonstrated in Dynatup and Izod impact tests at low temperatures down to—40°C. The level of toughness increase achieved by the addition of CaCO3 is close to the toughness produced using rubber at 23°C, and even better at lower temperatures.