FIRE CLAYS OF THE EASTERN COALFIELD OF KENTUCKY1

The eastern coalfield of Kentucky contains two horizons of workable refractory clays. One of these bearing flint, semi-flint and plastic clay is definitely proven to be of upper Pottsville age, and rests unconformably on the Mississippian formations. The other found in Boyd and eastern Carter County is in the Allegheny series and carries plastic fire clay of less commercial value. A number of points, not hitherto emphasized or noted are described.     

THE COMMERCIAL UNDERCLAYS OF INDIANA*

The commercial underclays of Indiana are used extensively in the manufacture of heavy clay products in that State; the use of native underclays for making pottery and refractories has been comparatively limited. Field and laboratory data relating to those underclays now being utilized by the clay plants of the State are summarized. The data, for the most part, are based upon field observations and laboratory tcsts made by the writer. The underclays are discussed with reference to their stratigraphical occurrences, physical characteristics in the outcrop, and physical properties as determined in the laboratory by chemical analyses and fire tests. The data selected for each underclay horizon are representative of the average quality of the clay used commercially from that horizon. Brief mention is made also of the qualities of underclays in horizons other than those being utilized at the present time.     

Catalytic chemical vapor deposition of methane on graphite to produce graphene structures

Graphene structures, obtained by catalytic chemical vapor deposition of methane on highly oriented pyrolitic graphite (HOPG), were examined using scanning tunneling microscopy. Depending on the Fe catalyst coverage and localization on the substrate steps and terraces, different graphene structures were obtained: curved graphene sheets at the edges of topmost stacked graphene bilayers, laterally grown terraces at the edges of individual graphene layers parallel to the HOPG basal plane and planar graphene islands on the terraces. A growth mechanism is proposed that takes into account the specific features of the spatial distribution of Fe catalytic nanoparticles on the substrate surface, driven by metal film-substrate interaction. The present synthesis approach is promising for the controlled growth and modification of graphene layers, as well as for engineering the edge characteristics of graphene systems at the atomic scales.     

Geochemistry of the Muthurajawela peat deposit of Sri Lanka

The Muthurajawela peat deposit of Sri Lanka has been studied for its geochemical distribution of 20 elements. There were no significant positive correlations of the metals with organic carbon. However, most metals, in particular Be, Zr, Li and the majority of the transition series metals, exhibit strong positive correlations with K, Al, Fe and Mn. Owing to the common occurrence of the latter elements in clay particles, this feature indicates the strong association of metals with the clay particles rather than with humic acids of the organic matter. The low pH of the peat bog presumably aids the conversion of the metals to ‘free’ ions which are in turn adsorbed on to clay particles. At low pH values the metal-organic complexes have low stability which accounts for the low metal-organic carbon correlations. However, due to the presence of marine-based sediments in the peat deposit, the metals could have been mobilized as chloro-complexes which were reduced to the free ion state by the effect of the humic acids. The general metal content of the peat deposit does not show enrichment compared to the average black shale, and the source of the metals is considered to be the laterites bordering the eastern part of the deposit and also the lagoonal sediments comprising the top and bottom horizons. Depth-element variations showed that the bottom horizon with abundant clay matter contains the highest amounts of the metals.     

Migration of radionuclides (Sr-90, Cs-137) in clays from the Austrian Molasse

The migration behaviour of Sr-90 and Cs-137 in freshwater- and marine clays from the Austrian Molasse was studied by percolating chloride solutions through small columns which contained undisturbed clay samples. The sorption capacity measured in the percolation tests was compared to that of batch tests which were done with the same clays respectively with different standard clay types.The sorption capacity generally increased with an increasing pH and with finer sieve fractions. For both clay types the sorption distribution coefficient K_d was higher for Cs than for Sr. The percolation in the column tests was carried out parallel and perpendicular to the bedding plane (ss). The sorption capacity was lower in the percolation test parallel ss because the permeability was higher and so the contact time was shorter. K_d is always distinctly higher for the marine clay in comparison to the freshwater clay. This may be explained by the lower permeability, the higher content of swelling clay phases, the different microtexture and the different primary interlayer cations of the marine clay.     

THE FIRE BRICK MATERIALS OF PENNSYLVANIA1

Pennsylvania produces over 40% of all clay fire brick and over 70% of all silica fire brick made in the United States. In 1920 Pennsylvania produced and sold fire clay worth nearly two million, fire clay brick worth nearly twenty-two million, and silica brick worth over ten and one-half million, a total of thirty-four and one-half million dollars worth of brick and clay. Three kinds of material are used for the manufacture of this fire brick. (1) Soft fire clay from one horizon northwest of Pittsburgh and from the “main clay” of the Pittsburgh bed south of Pittsburgh. (2) Hard or flint clay which occurs in many counties of the State. The hard clays are described as occurring at a limited number of horizons in the Allegheny formation or “Lower Productive Coal Measures,” as being irregular in thickness and distribution, ranging from a feather-edge to fifteen or twenty feet in thickness and being of two types, “block” clay in which the structure is homogeneous, and “nodular” clay in which the structure is gnarly or knotty. Brief reference is made to the principal flint clay deposits of the State. (3) The third source of material for fire brick is ganister rock, a pure white quartzite occurring as a massive bedded sandstone at the base of the Silurian series and exposed abundantly in the zig-zag ridges across the central part of the State and as a similar white quartzite at the base of the Cambrian in the southeastern part of the State. A series of tests of flint clays and of soft clays used to mix with the flint clays is appended. These are derived mainly from Clearfield County which is the leading flint clay county.     

Characterization,mechanical, and thermal properties of gamma irradiated starch films reinforced with mineral clay

Composite fabricated from starch and different concentrations of clay was prepared by solution casting method. The casted film was irradiated to different gamma irradiation doses 10, 20, 30, and 40 kGy. The dispersion of clay into starch was investigated by using X‐ray diffraction (XRD). The structural morphology of the composite was measured by scanning electron microscope and infrared spectroscopy. Film properties, such as water vapor transmission, mechanical, and thermal properties were also measured. The gel content and swelling behavior of the starch/clay composite were investigated. It was found that the gel content increases with increasing clay content and irradiation dose. The results obtained indicate that the starch/clay composite showed an increase in the tensile strength, thermal stability. Moreover, there is a decrease in water vapor transmission (WVRT) which improves its barrier properties. Both XRD and infrared spectroscopy showed that starch can be intercalated into the clay galleries. Also antibiotic drug Chlortetracycline HCl was loaded into the starch/clay composite by direct adsorption method. Chlortetracycline HCl adsorption capacity of composite was found to increase from 1.13 to 4.20 mg Chlortetracycline HCl per gram dry film with increasing amount of drug concentration. In vitro drug release studies in different buffer solutions showed that the basic parameters affecting the drug release behavior of the film are pH of the solution, drug concentration, and time. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Thermal,mechanical, and barrier properties of polyethylene/surlyn/organoclay nanocomposites blown films prepared by different mixing methods

(Low‐density polyethylene) (LDPE)/clay nanocomposites were prepared by melt blending in a twin‐screw extruder by using different mixing methods. Zinc‐neutralized carboxylate ionomer was used as a compatibilizer. Blown films of the nanocomposites were then prepared. The effect of mixing method on the clay dispersion and properties of the nanocomposites was evaluated by wide‐angle X‐ray diffraction analysis, mechanical properties, thermal properties, and barrier properties. The structure and properties of nanocomposites containing different amounts of nanoclay prepared by selected mixing techniques were also investigated. It was found that melt compounding of Surlyn/clay masterbatch with pure LDPE and Surlyn (two‐step‐a method) results in better dispersion and intercalation of the nanofillers than melt mixing of LDPE/Surlyn/clay masterbatch with pure LDPE and surlyn (two‐step‐b method) and direct mixing of LDPE with clay. The films containing ionomer have good barrier properties. A wide‐angle X‐ray diffraction pattern indicates that intercalation of polymer chains into the clay galleries decreases by increasing the clay content. Barrier properties and tensile modulus of the films were improved by increasing the clay content. In addition, tensile strength increased in the machine direction, but it decreased in the transverse direction by increasing the clay content. DSC results showed that increasing the clay content does not show significant change in the melting and crystallization temperatures. The results of thermogravimetric analysis showed that the thermal stability of the nanocomposites decreased by increasing the clay content more than 1 wt%. J. VINYL ADDIT. TECHNOL., 21:60–69, 2015. © 2014 Society of Plastics Engineers     

CO monolayer oxidation on stepped Pt(S) [(n − 1)(1 0 0) × (1 1 0)] surfaces

The electrochemical oxidation of CO has been studied on Pt(S)[(n − 1)(1 0 0) × (1 1 0)] electrodes to investigate the effect of the step density in the reaction. This series shows two different trends for long (n ≥ 7) and short terraces. For long terraces, the voltammetric peak shifts towards higher potential as the step density increases, unlike the behaviour observed for other stepped surfaces, which exhibit the opposite behaviour in agreement with the Smoluchowski effect. For short terraces, the “normal” behaviour is observed, that is, as the step density increases the peak shifts towards lower potentials. Chronoamperometric measurements were used to determine rate constants and Tafel slopes using the mean field Langmuir-Hinselwood kinetics. Rate constants follow the same trends as the peak potentials in voltammetry. A Tafel slope of 75 ± 4 mV has been obtained for the surfaces with long terraces whereas a value of the surfaces with short terraces showed a value of 100-120 mV is obtained. This change of slopes is interpreted as a change in the electrochemical behaviour of the species involved in the mechanism, probably, a change in the adsorption isotherm of adsorbed OH. Pt(5 1 0) electrode exhibits an intermediate behaviour between those of long and short terraces with two different peaks that can be associated with both behaviours previously described.     

Mechanical and morphological properties of organic–inorganic,hybrid, clay‐filled,and cyanate ester/siloxane toughened epoxy nanocomposites

Organic–inorganic hybrids involving cyanate ester and hydroxyl‐terminated polydimethylsiloxane (HTPDMS) modified diglycidyl ether of bisphenol A (DGEBA; epoxy resin) filled with organomodified clay [montmorillonite (MMT)] nanocomposites were prepared via in situ polymerization and compared with unfilled‐clay macrocomposites. The epoxy‐organomodified MMT clay nanocomposites were prepared by the homogeneous dispersion of various percentages (1–5%), and the resulting homogeneous epoxy/clay hybrids were modified with 10% HTPDMS and γ‐aminopropyltriethoxysilane as a coupling agent in the presence of a tin catalyst. The siliconized epoxy/clay prepolymer was further modified separately with 10% of three different types of cyanate esters, namely, 4,4′‐dicyanato‐2,2′‐diphenylpropane, 1,1′‐bis(3‐methyl‐4‐cyanatophenyl) cyclohexane, and 1,3‐dicyanato benzene, and cured with diaminodiphenylmethane as a curing agent. The reactions during the curing process between the epoxy, siloxane, and cyanate were confirmed by Fourier transform infrared analysis. The results of dynamic mechanical analysis showed that the glass‐transition temperatures of the clay‐filled hybrid epoxy systems were lower than that of neat epoxy. The data obtained from mechanical studies implied that there was a significant improvement in the strength and modulus by the nanoscale reinforcement of organomodified MMT clay with the matrix resin. The morphologies of the siloxane‐containing, hybrid epoxy/clay systems showed heterogeneous character due to the partial incompatibility of HTPDMS. The exfoliation of the organoclay was ascertained from X‐ray diffraction patterns. The increase in the percentage of organomodified MMT clay up to 5 wt % led to a significant improvement in the mechanical properties and an insignificant decrease in the glass‐transition temperature versus the unfilled‐clay systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Impact of large aspect ratio,shear-stiff,mica-like clay on mechanical behaviour of PMMA/clay nanocomposites

For the first time poly(methyl methacrylate) (PMMA) nanocomposites based on a synthetic shear-stiff, mica-like K-fluorohectorite clay were prepared by melt -compounding. Besides stiffness, this new synthetic type of clay offers very high aspect ratios above 600 after exfoliation, whereas a tailored surface modification of the clay yielded a good compatibility to the matrix material. The influence of different clay loadings (0–4 wt.-%) on mechanical behaviour of PMMA/clay nanocomposites were studied for two aspect ratios (≈55 and ≈620), set into correlation with morphology and compared to natural montmorillonite (MMT) clay, which has an aspect ratio of ≈50. It was found, that the use of these novel nanoplatelets leads to a significantly increased fracture toughness of about 25 and 70% in the case of an aspect ratio of 55 and 620, respectively, in comparison to neat PMMA, without sacrificing tensile strength. Scanning electron microscopy (SEM) analysis of the corresponding fracture surfaces and μ-computer tomography (μ-CT) revealed a high dispersion quality of the synthetic organo-clay in PMMA. Different fracture mechanisms could be identified. The presence of the nanofiller varies the local stress state in the matrix and promotes additional energy dissipating mechanisms like crack deflection, crack pinning as well as debonding effects with platelets pull-out leading to enhanced fracture toughness.     

Correlation of morphology,rheology, and performance improvement in gasoline tubes based on PA‐6 nanocomposites

PA‐6/organo‐modified layered silicate nanocompounds were prepared by the melt mixing of PA‐6 with different nanoclay loadings in a corotating twin‐screw extruder. Gasoline tubes based on these nanocompounds were produced at different silicate loadings. Thermal, mechanical, rheological, and barrier properties of the different samples were investigated and correlated to their morphology. Transmission electron microscopy, wide angle X‐ray scattering, and linear melt state viscoelastic measurements were used to characterize the different aspects of nanoclay dispersion in the nanocomposite samples. While tensile modulus, softening point, heat distortion temperature, and gasoline barrier properties of the prepared tubes were improved considerably by increasing the clay content, performance improvement with respect to clay content (after a certain value) decreased with increasing clay loading. It could be attributed to the re‐agglomeration of tactoids at higher concentrations. These findings were correlated with the rheological and morphological observations. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers     

Effect of long-term application of sewage sludge to a grazed grass pasture on organic carbon and nutrients of a clay soil in Zimbabwe

A study was conducted to assess the nutrient status of a Zimbabwean vlei clay soil grown to a Kikuyu (Pennisetum clandestinum Chiov.) grass pasture which had been amended with sewage sludge for 19 years. There was a significant (P<0.05) accumulation of organic C, mineral N, resin extractable P, and exchangeable K, Ca, Mg and Na in the top soil horizon. Organic C increased from 2.5 to 8.7% and 1.8 to 4.5% in the 0–5- and 5–10-cm horizons, respectively. Addition of sewage sludge resulted in a 19- and 57-fold increase in extractable P in the 0–5- 5–10-cm soil horizons, respectively. Exchangeable Na significantly (P<0.05) increased from 0.88 to 4.10 cmol/kg and from 1.04 to 3.06 cmol/kg in the 0–5- and 5–10-cm horizons, respectively. It was concluded that sewage sludge is a valuable source of nutrients and also provides an opportunity to increase soil organic matter.     

大牛地气田储层物性特征分析

大牛地气田主要目的层段储层的五性特征之间存在着一定内在的联系,其中岩性特征起着重要作用;油藏类型为碎屑砂岩油藏,总体表现为孔隙度低、渗透率低;由于沉积微相存在的差异,不同层位、气层组的储层具有不同的储层特征。     

Thermal,Rheological, and Mechanical Behaviors of LLDPE/PEMA/Clay Nanocomposites: Effect of Interaction Between Polymer,Compatibilizer, and Nanofiller

Summary: Linear low density polyethylene/maleic anhydride grafted polyethylene/montmorillonite clay (LLDPE/PEMA/clay) nanocomposites prepared using a co‐rotating twin screw extruder exhibit unique thermal, rheological, and mechanical behaviors. All the mechanical properties including ductility increase with clay loading. X‐ray diffraction analysis and TEM images reveal an intercalated clay structure for the LLDPE/PEMA/clay composite with 5% clay and an exfoliated structure for that with 2% clay. Differential scanning calorimetry shows that the addition of PEMA does not influence the melting temperature but favors the formation of more thin lamellas. Rheological characterization indicates that the LLDPE‐PEMA blend has similar rheological behavior to neat LLDPE, implying the two polymers are completely miscible. The composites exhibit significantly higher storage and loss modulus and complex viscosity at low frequencies, and the magnitude of all these properties increases with clay loading. Furthermore, the slopes of G′, G″, and complex viscosity versus frequency are similar for the composites of different phase morphologies, suggesting that the rheological behaviors of the composites depends more on clay loading than phase morphology. The enhanced miscibility between LLDPE and PEMA, and more importantly, interfacial interaction between clay, PEMA, and LLDPE, are responsible for the distinct improvement in all the mechanical properties of the composite, and in particular for the marked improvement in ductility.

Stress‐strain diagram for LLDPE, LLDPE/PEMA, and LLDPE/PEME‐clay nanocomposites.     

橡胶基体极性对高填充量橡胶/黏土纳米复合材料微观结构与性能的影响

研究了橡胶基体极性对高填充量橡胶/黏土纳米复合材料（RCNs）微观结构及性能的影响,探讨了硫化过程对极性环境不同的RCNs微观结构及性能的影响机理。研究表明：橡胶基体的极性对RCNs近程微观结构和远程微观结构都会产生一定的影响。RCNs中黏土片层会因高压作用（硫化过程）而发生远程聚集,但近程微观结构会因橡胶基体极性的不同而发生不同的变化;有机黏土的加入可以对RCNs的力学性能、气体阻隔性能有显著的改善。RCNs的力学性能与其远程微观结构关系密切;RCNs的气体阻隔性能则因黏土含量的不同而受到近程微观结构和远程微观结构的共同影响;远程微观结构较好的RCNs（如NBRCNs）的气体阻隔性能会在较低的黏土用量下进入增长平台阶段,黏土高用量情况下,相对气体透过率主要取决于近程微观结构。     

Nanocomposites from plasticized high‐amylopectin,normal and high‐amylose maize starches

Three types of maize starch with different amounts of amylose and amylopectin were used to prepare plasticized starch/clay nanocomposite films by casting. Studies by X‐ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the intercalation/exfoliation of the plasticized starch molecules took place into the clay galleries for the three types of starch. However, the plasticized waxy starch molecules were the easiest of them all to be intercalated/exfoliated, which was reflected in the highest increment of the stress at peak of these nanocomposites. Moreover, the lowest water uptake was showed by the plasticized high‐amylose starch/clay nanocomposites. It was concluded that varying contents of amylose and amylopectin influenced the formation of intercalated/exfoliated clay structures and also affected the interactions of clay with water. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

预膨胀法制备有机粘土/NBR纳米复合材料力学性能与微观结构的研究

采用预膨胀法制备有机粘土/丁腈橡胶（NBR）纳米复合材料,研究了预膨胀剂丙烯酸不同用量和其在有机粘土中不同质量分数对复合材料的力学性能和微观结构的影响。结构表明,丙烯酸用量为1g有机粘土/4mL丙烯酸和其在有机粘土中的质量分数为30%时,所制备的有机粘土/NBR纳米复合材料各方面性能达到最优。     

Influence of clay type on exfoliation,cure and physical properties of in situ polymerised poly(methyl methacrylate) nanocomposites

BACKGROUND: The nature of the dispersion of clay platelets in a resin composite will play an important role in the process of enhancement of the physical properties of that material. This paper examines how different modifiers and the quantity of surface treatment for the Cloisite^® range of organically modified clays affect properties in in situ polymerised poly(methyl methacrylate). Another clay which is a mixture of rod‐ and platelet‐like minerals is also investigated to understand how the shape of the clay particles can affect the polymer properties. RESULTS: Five different clays, including Cloisite 30B and Cloisite 15A, were dispersed using ultrasound and the cure of the samples was monitored using the Strathclyde Rheometer. Rheology, transmission electron microscopy and X‐ray diffraction were used to determine that a good level of clay dispersion was achieved. The mixed mineral formed the most stable dispersion seen from settling tests. CONCLUSIONS: The cure accelerated in the presence of organoclay, although the affect was less pronounced at higher temperatures. The glass transition temperature was increased by 20 °C with only a few weight percent of clay and water uptake was not adversely affected. Copyright © 2008 Society of Chemical Industry     

盐交换凹凸棒黏土的理化性质及其对双氯芬酸钠吸附性能的影响

将凹凸棒黏土采用不同价态的硫酸盐和相同价态不同用量硫酸盐交换后,通过红外光谱、扫描电镜、比表面积和ζ电位的测定,考察了盐交换处理对凹凸棒黏土微结构和理化性能的影响。在此基础上,考察了处理凹凸棒黏土对双氯芬酸钠的吸附影响。结果表明,金属盐交换凹凸棒黏土对双氯芬酸钠的吸附量不仅与所交换金属离子的价态有关,更与凹凸棒黏土的微孔比表面积和微孔体积有关。当硫酸铝用量为凹凸棒黏土量的0.5%时,其交换凹凸棒黏土对双氯芬酸钠的吸附量最大,达到了126 mg/g,与凹凸棒黏土原矿相比,吸附量提高了近4倍。