Calcium Carbonate And Acetic Acid
Calcium Carbonate
M.M.H. Al Omari , ... A.A. Badwan , in Profiles of Drug Substances, Excipients and Related Methodology, 2016
1.1 Nomenclature
1.i.i Systematic Chemical Names
-
Calcium carbonate [one,ii].
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Carbonic acrid calcium common salt (i:i) [ane].
i.1.2 Nonproprietary Names
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Recommended international nonproprietary proper name: Calcium carbonate [3].
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Synonyms: E 170, calcite, aragonite, vaterite, chalk, CI pigment white 18 [4], drop chalk, prepared chalk, whiting, English white, Paris white [five].
i.one.3 Proprietary Names
Caltrate (Pfizer Consumer Healthcare), Maalox Quick Dissolve (Novartis Consumer Healthcare), Maalox Regular Force (Novartis Consumer Healthcare), Bone-Cal (Glaxo SmithKline), Alka-Seltzer (Bayer), Alcalak (Medique Products), Oyster Crush Calcium (Swanson Health Products), Oysco (Rugby), Cal-Gest (Rugby), Icar Prenatal Chewable Calcium (Hawthorn Pharmaceuticals), Oyster Shell Calcium (Swanson Health Products), Children's Pepto (Procter & Gamble), Rolaids Soft Chew (Johnson & Johnson), Adcal 1500 Chewable (Biokirch), Ostocal (Hikma Pharm.) [6], Calcichew (Takeda), Calcichew 500 mg purutabletti (Takeda), Calcichew Spearmint 500 mg purutabletti (Takeda), Calcimagon 500 mg (Takeda), Calcioral (Takeda), Mastical (Takeda), Calcitugg (Takeda) [3], Boots Indigestion Relief (The Boots Company Plc), Cacit (Warner Chilcott United kingdom Ltd), Remegel (SSL International Plc), Setlers Antacid (Thornton & Ross Ltd), Tums Assorted Fruit Antacid (GlaxoSmithKline Consumer Healthcare) [7], Calcidia (Bayer Healthcare) [5], Adcal 500 (JPM), Oystercal (United Pharma) [viii].
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Calcium carbonate nanocomposites
Y. Lin , C.-Yard. Chan , in Advances in Polymer Nanocomposites, 2012
3.one Introduction: applications of calcium carbonate nanoparticles
Calcium carbonate particles have been used in the plastics industry for many years. The original purpose of adding ground calcium carbonate (GCC) particles as filler textile for plastics was to reduce textile costs. With the development of precipitated calcium carbonate (PCC) particles, which are smaller than GCC particles, many more than industrial applications for this type of nanocomposite accept emerged. Many recent studies have shown that PCC nanoparticles can be used as fillers not but to reduce the cost of materials merely also to improve the mechanical properties of the polymers. The purpose of this paper is to review the uses of PCC particles in polymer nanocomposites and the toughening mechanisms of the nanocomposite materials.
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SURFACES, Chemistry & APPLICATIONS
JOSÉ MIGUEL MARTÍN-MARTÍNEZ , in Adhesion Science and Applied science, 2002
4.iv.4 Calcium carbonate
Calcium carbonate (CaCO 3) is the about widely used filler in polymer formulations. As a filler, calcium carbonate allows cost reduction and improved mechanical properties. It is found in sedimentary rocks (chalk, limestone), marbles and minerals (dolomite). Some typical properties are: density 2.7-ii.9 one thousand/cmiii; pH of water pause nine; particle size 0.2-30 μm; oil absorption thirteen–21 thou/100 g; specific surface area 5–24 m2/g. Depending on their origin and history of formation, and their impurities, the calcium carbonates take different properties. Iii major technological processes are used in the production of calcium carbonate fillers: milling, precipitation, and coating. However, most calcium carbonate fillers are processed past milling using a dry or wet method. Dry milling provides ultra-fine calcium carbonate grades (particle size nigh 0.half dozen μm). Natural milled calcium carbonates are added to subtract cost in condom base of operations adhesives.
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CO2 Chemical science
Hannu-Petteri Mattila , Ron Zevenhoven , in Advances in Inorganic Chemical science, 2014
1 Introduction
Calcium carbonate (CaCO three) is a substance widely used for various purposes, for example, as a filler and pigment fabric not only in paper, plastics, rubbers, paints, and inks just besides in pharmaceutics, cosmetics, construction materials, and asphalts and as a nutritional supplement in beast foods (one) . As well the and so-chosen ground calcium carbonate (GCC), which is milled from natural limestone, precipitated calcium carbonate (PCC) is used in applications where, for case, higher brightness or a narrow particle size distribution is required. In PCC, manufacturing these properties can exist controlled, since dissimilar GCC, the production is fully constructed (two) . Figure ten.1 shows the demand distribution between the different applications in North America, paper filler being the major utilise of PCC. In 2011, 14 Mt of PCC was consumed worldwide, Asia being the largest regional market place. GCC consumption reached 60 Mt in 2011, since as a cheaper, less processed production, it has a wider area of applications. The estimated production capacity of PCC and GCC combined exceeds 100 Mt/year, of which ~ 17 Mt is PCC production (2,3) .
Figure x.1. 2011 PCC consumption by cease utilise in North America in kilotons.
Information from Ref. (2) .Carbon dioxide for PCC manufacturing is in general taken from cleaned flue gases of industries located nearby the PCC plant, thus reducing the CO2 emissions from this specific source. However, the production of reactive calcium from limestone usually generates an amount of COtwo equal to or larger than what is chemically stored in carbonates (1) . Thus, in instance calcium could be brought into a PCC manufacturing process with a smaller carbon dioxide penalty, the procedure route would contribute to mitigating CO2 emissions and global climatic change. Carbon dioxide would be stored equally a solid and stable mineral past using the technology unremarkably known as mineral carbonation (4) .
Applicability and process economic science of several calcium-containing solid industrial waste materials, such as steel slag (five–x) , air pollution control residue (11,12) , bottom ash from municipal solid waste or refuse-derived fuel incineration (6,12,13) , oil shale ash (14) , waste concrete (fifteen–17) , cement kiln dust (CKD) (18) , and brines (nineteen,20) , for mineral carbonation in general take been studied during recent years. Examples of primary elemental composition of these materials are presented in Tables 10.1 and 10.2 in Section four.
Table ten.1. Main elements in diverse industrial waste matter materials excluding atomic number 26 and steelmaking slags
| Material | Analysis method | Ca | Mg | Atomic number 26 | Al | Si | Na | South | K | Mn | Ba | Sr | Rest | Refs. | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Air pollution control rest | ICP–AAS | % | 35.0 | 0.8 | 0.1 | 0.ii | one.0 | 3.eight | – | 0.six | – | – | – | 58.v | (21) |
| Brine (average of five samples) | ICP | mg/L | 33,450 | 1837 | 434 | – | – | 62,780 | – | 2350 | – | 917 | ten,041 | – | (19) |
| Brown coal wing ash | ICP | % | 21.two | xv.iv | 7.eight | one.three | iv.three | 4.8 | 6.0 | 0.4 | – | – | – | 38.8 | (22) |
| Cement kiln dust (typical) | – | % | 27.2–35.7 | < ane.2 | 0.7–2.8 | 1.6–3.2 | five.one–7.v | < ane.v | 1.vi–7.2 | two.5–x.8 | – | – | – | 32.8–61.three | (18) |
| Estonian oil shale ash | ICP | % | 21.5 | iii.0 | two.0 | 3.4 | 0.2 | 0.ix | two.4 | ane.7 | 0.4 | – | – | 64.5 | (23) |
| FGD gypsum | XRD/other | % | 23.2 | – | 0.one | 0.two | 0.three | – | 17.ix | 0.1 | – | – | – | 58.two | (24) |
| Lignite wing ash | ICP–AES | % | 12.8 | 3.7 | five.ix | 7.nine | 24.1 | iv.1 | – | 2.3 | – | – | – | 39.2 | (20) |
| Paper bottom ash | XRF | % | 22.ane | 3.i | two.eight | 7.2 | xvi.6 | 0.6 | 0.4 | 1.3 | 0.2 | – | – | 45.seven | (25) |
| Phosphogypsum | XRF | % | 31.9 | 0.1 | – | 0.one | 0.ii | 0.9 | 20.1 | 2.3 | – | – | 0.1 | 44.ii | (26) |
| Pulverized coal fly ash | SEM–EDS | % | 0.9 | – | 2.eight | xiv.5 | 16.viii | four.4 | – | 1.six | – | – | – | 59.0 | (27) |
| Waste product cement | ICP–AES/XRF | % | 23.viii | 0.1 | 2.five | 0.7 | 2.ix | – | – | – | – | – | – | 71.one | (28) |
Tabular array 10.2. Chemical compositions of various iron and steelmaking slags measured by XRF analysis (29)
| Slag | CaO | Fe | SiO2 | Mn | MgO | Al2O3 | V | Na2O | P | Due south | KtwoO | Ti | Cr | Rest |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Blast furnace | 34.5 | 0.ii | 31.two | – | xvi.2 | 12.vii | – | 0.7 | – | two.6 | 0.5 | one.3 | – | 0.1 |
| Desulfurization | 58.0 | 7.0 | 15.0 | 0.3 | i.three | 2.5 | 0.1 | 3.1 | – | 2.9 | 0.ane | 1.0 | – | 8.7 |
| Steel converter | 45.2 | 16.vii | 11.iv | 2.six | 1.5 | one.4 | 1.2 | – | 0.4 | – | – | 0.six | 0.ii | 18.8 |
| Ladle | 49.four | 4.4 | 14.i | 0.seven | 5.8 | 21.0 | 0.3 | – | – | 0.2 | – | 0.seven | – | 3.4 |
For PCC manufacturing, however, it is essential to guarantee a high product quality, especially high purity, as well as a suitable particle size and crystal morphology (30) . Assuming that these backdrop are not compromised, the product could be marketed as a replacement for PCC produced with traditional methods. This would, besides reducing industrial waste streams and CO2 emissions, as well bring directly economic benefits for applying new PCC manufacturing routes similar Slag2PCC—come across Section 5.seven (31) .
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COMPOUNDING MATERIALS
Peter A. Ciullo , Norman Hewitt , in The Rubber Formulary, 1999
Calcium Carbonate
Calcium carbonates for safety, often referred to as "whiting", fall into 2 general classifications. The first is moisture or dry ground natural limestone, spanning boilerplate particle sizes of 5000 nm down to about 700 nm. The second is precipitated calcium carbonate (PCC) with fine and ultrafine products extending the average size range down to 40 nm.
Footing natural products evidence low anisometry (specific shape depends on grinding procedure), low surface area and depression surface activity. They are widely used in safety, nevertheless, because of their low toll, and because they can exist used at very high loadings with footling loss of compound softness, elongation or resilience. This all follows from the relatively poor polymer-filler adhesion potential, equally does poor abrasion and tear resistance. Dry out-ground limestone is probably the to the lowest degree expensive compounding cloth available and more tin exist loaded into rubber than whatsoever other filler. Water-ground limestone is somewhat more than expensive, but offers improve uniformity and finer particles size.
The much smaller size of precipitated calcium carbonates provides a corresponding increase in surface surface area. The ultrafine PCC products (<100 nm) can provide surface areas equivalent to the hard clays. Manipulation of manufacturing weather allows the production of precipitated calcium carbonates of two singled-out particle shapes. Precipitated calcites are essentially isometric particles, while precipitated aragonites are acicular. Precipitated calcite is the form more often than not used in prophylactic compounding.
Stearate-treated versions of both the footing and precipitated calcium carbonates are available. The surface coating controls moisture assimilation, improves dispersion, promotes better elastomer-particle contact, and protects the calcium carbonate from decomposition past acidic ingredients or compounding reaction products. Since calcium carbonate offers no reactivity toward silanes, analogues to the silane treated clays and synthetic silicas do non exist. There is, however, an ultrafine PCC with a reactive surface coating of chemically bonded carboxylated polybutadiene polymer. With either sulfur or peroxide vulcanization, crosslinking occurs between the elastomer and the carboxylated polybutadiene coating. This provides the highest level of reinforcement amongst the PCC products, comparable to thermal blacks.
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Research Methods in Biomineralization Scientific discipline
Christina R. Blueish , ... Patricia Chiliad. Dove , in Methods in Enzymology, 2013
1 Introduction
Amorphous calcium carbonate (ACC) is at present recognized in a wide diverseness of natural and engineered environments. ACC can be institute in some soils and sediments ( Jones & Peng, 2012; Sanchez-Roman et al., 2008) and its formation has applications for controlled synthesis in biomedicine and materials sciences (Han & Aizenberg, 2008; Lee et al., 2012). Of detail interest is the ACC that forms during skeletal biomineralization of calcifying organisms (Addadi, Joester, Nudelman, & Weiner, 2006; Politi, Arad, Klein, Weiner, & Addadi, 2004; Tao, Zhou, Zhang, Xu, & Tang, 2009). Label studies show that ACC is a truly amorphous phase, with a typical limerick of CaCO3·H2O, and it exhibits a unique curt- and intermediate-range structure (Michel et al., 2008). The realization that ACC can be a reactive precursor to a number of crystalline polymorphs of CaCO3 has motivated an extensive endeavour to empathise the influence of the inorganic and organic factors on ACC composition. For example, the biomineralization community is interested in whether calcification by an ACC pathway affects the Mg content of calcitic biominerals that are used as proxies for seawater temperature (Dissard, Nehrke, Reichary, & Bijma, 2010; Stanley, 2006).
Previous studies of ACC take provided of import insights into ACC properties, only a quantitative understanding is not nevertheless established. This is partially because electric current synthesis procedures are unable to command solution chemistry. For instance, a widely used synthesis method involves batch mixing of Na2CO3 and CaClii solutions, then filtering the precipitate (Koga, Nakagoe, & Tanaka, 1998). Nonetheless, the closed configuration of this "batch" method inherently causes solution composition to change significantly during synthesis, and the NaiiCOiii salt increases solution pH to values that are college (pH eleven–13.5) than virtually natural systems. Another popular approach diffuses (NHfour)2CO3 into CaCl2 solutions to increase supersaturation and induce ACC formation (Aizenberg, Addadi, Weiner, & Lambert, 1996; Wang, Wallace, De Yoreo, & Dove, 2009). This method produces ACC nether highly variable and uncontrolled supersaturation conditions, introduces meaning amounts of into the mineralizing solution, and yields a limited amount of ACC.
To overcome these limitations, we developed a new procedure for ACC synthesis (Fig. 23.1) that uses a mixed menses reactor (MFR) arrangement to maintain abiding and controlled solution chemistries. This new procedure for producing ACC is adapted from an earlier method that was used for kinetic studies of mineral growth (Saldi, Jordan, Schott, & Oelkers, 2009) and dissolution (Rimstidt & Dove, 1986). The MFR offers a number of advantages over batch and diffusion methods: (i) allows precise control over supersaturation, (two) produces ACC at steady-state conditions, and (3) yields large amounts of ACC with reproducible compositions. We demonstrate this approach by quantifying the factors that influence the Mg content of ACC by producing Mg-ACC from well-characterized solutions under controlled weather.
Figure 23.1. Schematic of the mixed flow reactor system. Arrows indicate the direction of menses. Black star denotes the location of the 0.twenty μm nylon filter.
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Poly(Vinyl Chloride)
Professor Marianne Gilbert , Mr. Stuart Patrick , in Brydson's Plastics Materials (8th Edition), 2017
thirteen.8.5.i Calcium Carbonate
Calcium carbonate (besides known as chalk), mined equally calcite, is the most unremarkably used filler for PVC. It is discussed in detail in Section viii.4.ane. Information technology is usually surface treated with stearic acrid, producing a layer of calcium stearate on the filler surface. This results in improved processing and dispersion (mechanical backdrop) and improved moisture resistance giving meliorate electrical properties.
Synthetically precipitated calcium carbonates (PCC) are also used in PVC. These have a fine particle size suitable for use in high-performance areas. Surface treatment is besides normal.
Particle size is important and, for some applications requiring skilful weathering and touch performance (window profile), the ultrafine milled, high whiteness, natural version is normally used. Coated ultrafine and precipitated calcium carbonates besides have a positive effect on bear upon properties in impact modified formulations. The annoying wear of calcium carbonate, on melt processing equipment, is not considered significant but increases with increasing levels.
Calcium carbonate nanoparticles are commercially available and are claimed to requite a cost-effective mode of increasing impact force; their use in impact modified PVC has improved mechanical properties.
Chalk fillers also have extensive use in PVC-P applications where the particle size restriction is not so essential. Higher addition levels can likewise be accommodated. They have all-encompassing use in wire and cablevision where they assist, in combination with other additives, in reducing HCl generation in a fire situation. PVC plastisols generally accept loftier filler loadings for cost reasons but demand to retain the appropriate viscosity and rheology for the processing technique used. Specific grades of calcium carbonate are available for these applications.
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Fillers and reinforcements
Clive Maier , Teresa Calafut , in Polypropylene, 1998
4.ii Calcium carbonate
Calcium carbonates are one of the about abundant minerals in the world's crust. They occur in the form of limestone and chalk, formed from fossils, and marble, formed from the metamorphosis of sedimentary stone. They consist mostly (>98%) of calcium carbonate (CaCO iii), with trace amounts of magnesium carbonate, iron oxide, and aluminum silicates. Dolomite is a blend of calcium and magnesium formed past metamorphosis. All are relatively soft minerals (Mohs hardness of 3), white in colour, with a specific gravity of 2.71 at 23°C (73°C). Physical properties of calcium carbonate, talc, mica, and barite are given in Table 4.one. A photomicrograph of calcium carbonate particles is shown in Figure four.iii. [854, 860, 828, 827, 942]
Table 4.one. Physical Properties of Ordinarily Used Minerals
| Property | Barite | Talc | Calcium Carbonate | Mica (phlogopite) |
|---|---|---|---|---|
| Particle shape | Orthorhombic | Platy | Orthorhombic | Platy |
| Specific gravity | 4.five | ii.8 | 2.7 | 2.8 |
| Chemic resistance | ||||
| Acids | Excellent | Proficient | Poor | Practiced |
| Alkali | First-class | Good | Off-white | Expert |
| Thermal stability (°C) | 1580 | 900 | 680 | 1500 |
| pH (x% solution) | 6.5–7 | nine | 9–9.v | ix–9.5 |
| Hardness (Mohs scale) | 2.five | ane | 3 | ii.five |
| Thermal conductivity (cal/cm south °C) | 6x10–3 | 5x10–iii | five.6x10–3 | 16x10–three |
| Specific heat (cal/g °C) | 0.eleven | 0.208 | 0.205 | 0.206 |
| Coefficient of thermal expansion (cm/cm/°C) | 10 | 8 | 10 | 25 |
| Oil absorption | six | 25 | 10 | 25 |
| Dielectric constant | half-dozen.1 | 7.five | 6.one | 5.5 |
| Refractive alphabetize | 1.65 | one.59 | 1.half-dozen | 1.54–1.69 |
| Brightness (Hunter L, 325 mesh powder) | 84–96 | 78–95 | 78–98 | 38–45 |
Figure four.3. Micrographs of spherically shaped mineral fillers. a) calcium carbonate b) barite [942]
Calcium carbonate is the well-nigh widely used filler for plastics. Information technology is inexpensive and tin can be used at high loadings. It is generally used equally an extender; however, information technology can improve stiffness and impact strength, especially with fine particle grades. The flexural modulus of a 40% calcium carbonate-filled polypropylene homopolymer is almost 3000 MPa (400,000 psi), midway between unfilled and talc-filled resins. Calcium carbonates provide high brightness and high gloss. Limestone- and marble-based products are generally used when artful considerations are of import; the corporeality of the more expensive titanium dioxide pigment in a formulation can be reduced by up to 50%, with equivalent whiteness, past substitution of calcium carbonate. Disadvantages include lowered tensile strength and compressive force, greatly reduced elongation, and low resistance to organic acids. [847, 159, 697, 849, 866, 851, 827]
Calcium carbonates are available in different grades: dry processed, wet or water ground, beneficiated ground, precipitated, and surface-treated. Precipitated is a synthetic form produced by carbonization and is available in very fine particle sizes (0.vii–2.0 μm). Surface treated grades are coated with lipophilic substances such as stearic acid or calcium stearate to improve dispersibility, increase oxidation resistance of the filled resin, and reduce wear on processing machinery. In experimental studies, coated calcium carbonates resulted in higher values for impact strength and elongation at break and enhanced whiteness compared to un-coated grades. In beneficiated ground, the most widely used grade, iron and silica are removed to minimize resin degradation, and the mineral is finely ground, with median particle sizes of 1–ten μm. The largest particle size (>12μm) is obtained with dry candy grades; coarse particles are removed in moisture ground grades, with a median particle size of >3 μm. [827, 866, 854, 942]
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Research Methods in Biomineralization Science
Jinhui Tao , in Methods in Enzymology, 2013
4.2.v Data analysis
Calcium carbonate polymorph contents have been determined by quantitative analysis of FTIR spectra ( Vagenas, Gatsouli, & Kontoyannis, 2003). To calculate of area ratio of component summit 875 cm− ane to pinnacle 866 cm− i, the program PeakFit 4.12 (SeaSolve Software Inc.) was used. The spectra in the range from 700 to 1000 cm− one were selected for data processing. The auto-baseline subtraction was performed before the peak fitting. Gaussian (amplitude) functions with variable widths were used to fit all the peaks in spectra. The hidden peaks were found by rest method. Typically, a residual was merely the departure in y-value between a data point and the sum of component peaks evaluated at the aforementioned information point x-value. Past placing peaks in such a mode that their total expanse equaled the area of the data, the hidden peaks could be revealed by these residuals. The amplitude of the threshold value was inverse to clear possible racket peaks. The iterations continued until a goodness of fit R 2 > 0.99 and the change of R 2 < 0.001 between each of the two iterations was obtained (Fig. 22.ivC).
SEM imaging of sample cross sections was used to study the morphology and stage of different layers in intermolt cuticle (Fig. 22.threeA ). The distal epicuticle is almost 1 μm in thickness. This outermost layer may deed as a sensilla and it is not mineralized (Hild et al., 2008). The exocuticle is a 15 μm layer with a distal smoothen part and a rough transition part. Within the endocuticle, sublayers of plywood-like stacks of parallel fibers are visible. The membranous layer composes loosely stacked platelike structures. The phase and organic data of mineralized layers is nerveless under Raman spectroscopy. The bands due to carbonate stretching vibration accept their maxima at 1086 and 1078 cm− 1 for calcite and ACC, respectively (Hild et al., 2008; Wang, Wallace, De Yoreo, & Pigeon, 2009). These two phases tin besides exist distinguished past the lattice vibration at 280 cm− 1 of calcite and a broad band from 100 to 300 cm− 1 of ACC (Hild et al., 2008; Wang et al., 2009). It is found that the up layer of exocuticle consists of calcite (1 in Fig 22.3B and C). ACC and calcite coexist at the boundary between exocuticle and endocuticle (2 in Fig 22.iiiB and C). The bands of organic species bear witness their maxima at 1370, 1326, 1104, and 953 (4 in Fig 22.threeB and C, Table 22.3), which match well the Raman peaks of α-chitin (Brunner et al., 2009; Ehrlich et al., 2007; Zhang, Geissler, Fischer, Brendler, & Bäucker, 2012). The endocuticle is constructed by ACC and α-chitin (3 in Fig 22.3B and C). The membranous layer contains much higher percentage of α-chitin than other layers (4 in Fig 22.3B and C). The inhomogeneous distribution of inorganic/organic could be the reason for loftier mechanical holding as well as the recycling of minerals during the molt cycles.
Figure 22.3. Construction, chemistry, and phase distribution in an intermolt cuticle. (A) SEM image of sagittally broken fully mineralized cuticle of Armadillidium vulgare. The cross department of cuticle showed the thin epicuticle (ep), calcified exocuticle (ex) and endocuticle (en), and membranous layers (ml). 1–4 indicated the positions where Raman spectra were collected. (B) Raman spectra recorded at corresponding sites indicated in A. The spectrum of sternal ACC was used as the dissimilarity. (1) Exocuticle contained well-crystalline calcite and pocket-sized ACC. (2) Purlieus between exocuticle and endocuticle was composed of ACC and minor calcite. (3) Endocuticle was composed of ACC phase without any detectable calcite. (4) Boundary between endocuticle and membranous layers was composed of ACC and α-chitin. (C) A magnified paradigm of spectra in B.
Table 22.3. Raman spectra and assignments of intermolt cuticle, frequency (cm− 1)
| Raman | Assignment |
|---|---|
| 3459 | Disordered hydrogen bond |
| 3268 | Ordered hydrogen bail |
| 2965 | CH3 asymmetric stretch |
| 2937 | C–H of CH3 stretch |
| 2884 | C–H of band stretch |
| 1660 | Amide I |
| 1619 | Amide I |
| 1447 | CH2 bend |
| 1412 | CH2 bend |
| 1370 | CHtwo rocking |
| 1326 | Amide 3 |
| 1262 | Amide Three |
| 1200 | Amide Iii |
| 1147 | C–O–C, C–O stretch |
| 1104 | C–O–C, C–O stretch |
| 1086 | Symmetric stretch of in calcite |
| 1078 | Symmetric stretch of in ACC |
| 953 | CH 10 bend |
| 895 | CH 10 curve |
| 712 | In-airplane bend of |
| 500 | C–C backbone |
| 456 | CCC ring deformation |
| 398 | CCC ring deformation |
| 367 | CCC ring deformation |
| 320 | CCC ring deformation |
| 280 | Lattice rotational mode of calcite |
| 156 | Lattice translational way of calcite |
Nosotros also designed some in vitro experiments to evaluate the office of aspartic acid and magnesium during the ACC transformation (Fig. 22.4). The crystallization degree of the calcium carbonate is quantitatively estimated by the area ratio between corresponding component ν 2 peaks at 875 cm− i of calcite and 866 cm− 1 of ACC in FTIR (Fig. 22.4C). This ex situ method based upon v ii symmetry and position is more than sensitive than the previous interpretation past using v two:v 4 ratio (Beniash et al., 1997; Politi et al., 2004) so that information technology can even monitor poorly crystallized calcium carbonate samples. Polarizing microscopy is also used to monitor in situ the nucleation of crystals (vivid domains) in the bulk solutions. The induction time of phase transformation tin exist estimated by these two complementary methods, and the results match each other well (Fig. 22.fourB). The crystallization of ACC in pure water is too fast, and so a mixed solvent containing h2o and diethylene glycol (DEG, a solvent model for hydroxyl rich chemical compound chitin) is used as the dispersing media to wearisome down the crystallization rates. In all experiments, the h2o/DEG volume ratio is fixed at 0.8, which is close to the reported water content in cuticle of Armadillidium vulgare, 40–threescore wt% (Lindqvist, Salminen, & Winston, 1972). In our written report, the additives concentrations are represented by their final concentrations in aqueous component. When the ACC contacts h2o/DEG, the nucleation of calcite occurs inside simply ~18 min (blueish in Fig. 22.fourA and D). Nevertheless, the spontaneous transformation of ACC in the solvent is effectively switched off; no phase transformation is detected even at 40 h in the presence of only 5 mM magnesium (greenish in Fig. 22.ivA and D). Thus, the lifetime of ACC in the solution is significantly increased so that this unstable phase can be temporarily stored.
Figure 22.iv. Kinetics of phase transformation from ACC to calcite. (A) FTIR spectra of slightly crystallized samples extracted at different timescales nether different conditions. (B) The optical images of in situ stage evolution investigated by polarizing microscopy (Scale bar is 100 μm) in the solvent. The calcite and ACC phases are expressed as the bright and night on the epitome, respectively. The bright densities can reflect the crystallization degrees during the transition visually. (C) Calculation methods for crystallization degree of calcium carbonate. The asymmetric ν 2 peak of calcium carbonate tin can be decomposed into two symmetric component peaks at 875 cm− 1 (calcite) and 866 cm− 1 (ACC), respectively. The area ratio between these ii peaks was used every bit a measurement of crystallization degree. (D) Kinetic plot of phase transformation in the absence and presence of magnesium and Asp.
Asp is also a stabilizer of the ACC stage. The induction time of ACC nucleation is prolonged to 50 min in the presence of 7.five mM Asp (olive in Fig. 22.4A and D). Although Asp poorly inhibits the crystallization of pure ACC, information technology tin switch on the crystallization of the Mg-stabilized ACC. When the same amount of Asp is added into a prestabilized magnesium–ACC arrangement (the concentration of magnesium is maintained at 5 mOne thousand), the magnesium-stabilized ACC becomes unstable and the crystallization tin can be triggered inside 17 h (red in Fig. 22.ivA and D). This promotion effect is Asp dose-dependent as the consecration time increases to 21 h when the Asp concentration is reduced to five chiliadGrand (purple in Fig. 22.ivA and D). The combination of in situ polarizing microscopy and FTIR (Fig. Fig. 22.4A and B) demonstrates that the stability of ACC (the transition from ACC to calcite) can be tuned over a wide range past using magnesium together with Asp.
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Polymer Matrix Composites
P.K. MALLICK , in Comprehensive Composite Materials, 2000
2.09.2.ane.1 Calcium carbonate
Calcium carbonate (CaCO 3) is the most commonly used filler in the plastics industry. It is not simply used with several thermoplastics, such as PVC (e.grand., in PVC pipes and floor tiles), but as well with thermosets such equally polyesters (in canvas molding compounds). Calcium carbonate is abundantly available in nature as limestone, chalkboard, or marble and CaCOiii fillers from these minerals can be produced at very low price. Iii forms of CaCOiii fillers are used; arranged in the social club of purity, they are dry processed, beneficiated, and precipitated. Calcium carbonate is considered a soft, nonabrasive filler. Its natural colour is white, nonetheless, it can exist hands colored. It is chemically stable up to 800°C and above this temperature it dissociates into calcium oxide and carbon dioxide. It is available in both untreated and surface treated weather condition; the well-nigh common surface treatments are stearic acid and calcium stearate.
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Calcium Carbonate And Acetic Acid,
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