Increase Of Kaolin Content Research Articles

Microrheological Phenomenon and Mechanical Properties of High-Aspect-Ratio Microgroove Injection Moulding of Kaolin/PP Composites.

The microrheological phenomenon of kaolin-filled polypropylene (kaolin/PP) composites was investigated for the first time. The microviscosity of kaolin/PP composites was studied by changing the melt temperature and shear rate. Then, injection moulding experiments of rectangular microgrooves with different aspect ratios using kaolin/PP composites and mechanical property tests of the samples were carried out. The results showed that with increasing kaolin content, the microviscosity of the kaolin/PP composites gradually increases. The shear rate had the greatest influence on the microviscosity, and the kaolin content had the least influence. When the aspect ratio of rectangular microgrooves is small, with an increasing kaolin content, the microgroove filling rate increases, and the microstructured sample geometric shape replication effect is good; however, when the aspect ratio reaches 10:1, the microgroove filling rate decreases with an increasing kaolin content. The microstructured sample geometric shape replication effect is also poor, and size effects appear. Different factors control the microrheological morphology of composites with different aspect ratios, including the shear deformation and viscous flow of composites. The increase in kaolin content leads to a decrease in the friction coefficient and an increase in the wear resistance of the composites. We concluded that the best composite formulation for kaolin/PP composites in microinjection is the 7KL/PP composite with 7% kaolin. When the aspect ratio is 5:1, the reproduction of the microstructured sample geometry is the best, and the comprehensive mechanical properties of the sample are the best.

Development and characterization of microstructural and mechanical properties of hybrid polystyrene composites filled with kaolin and expanded polyethylene powder

This study investigated the microstructural and mechanical properties of hybrid composites developed by the reinforcement of solvated polystyrene with expanded polyethylene powder and kaolin. The hybridized composites were synthesized using hand layup and cold mixing methods, and cured at room temperature for 3 days. The characterization was done using Fourier transform infrared spectroscopy (FTIR) and the scanning electron microscope coupled with energy dispersive spectroscopy (SEM-EDS), while the mechanical characteristics of the developed composites were evaluated by the Rockwell Hardness ASTM D785 standard. It was observed that an increase in kaolin content, at the expense of the polyethylene powder, increases the hardness strength of the composites, with the hardest composite (96.3 HRB) being obtained at a 25% kaolin mixer. The FTIR results revealed the presence of various functional groups, while the SEM analysis showed that the smoothness of the composite's surfaces increases with increase in kaolin content. The EDS analysis revealed the presence of several elements, mostly from the kaolin filler, suggesting the reason for its high density impacted on the kaolin/polyethylene filler composites. The importance of the study is the conversion of more than one solid waste into new and useful products.

Application of PI-FBG sensor for humidity measurement in unsaturated soils

In this paper, the polyimide-coated fiber Bragg grating (PI-FBG) humidity sensor suitable for use in unsaturated soils was developed. Through a series of laboratory tests, the pore gas relative humidity in different sand-kaolin mixtures were measured and analyzed to verify the feasibility of the sensor in unsaturated soils. The results shows that the pore gas relative humidity in unsaturated soils first increases rapidly and then tends to be stable with the increase of water content. The relationship between them can be fitted by quadratic function when the pore gas relative humidity is less than 100%. In addition, the critical water content (w100%RH) of mixed soils increases linearly with the increase of kaolin content; when the water contents of mixed soils are same, higher kaolin content induces higher pore gas relative humidity.

Characterization of Hydration Behaviour and Modeling of Film Formulation

Hydration behavior of hydrogel-based polymeric film possesses great importance in mucosal drug delivery. Modified Lag phase sigmoid model was used for the investigation of hydration of the film. Kaolin incorporated HPMC K100LVCR (HL) and K100M (HH) films containing dexamethasone as a model drug have been prepared for studying swelling kinetics. Swelling of HL and HH films was decreased with the gradual increase of kaolin content and HH of higher viscosity has shown higher value than HL matrix. Kaolin also inhibited the film erosion process. Mathematically modified lag phase sigmoid model demonstrated similarity of the predicted swelling content with the observed value. High R2 and small RMSE value confirmed the successful fitting of the modified lag phase sigmoid model to the experimental data of swelling content. τ value similar to the observed one was obtained. This modified model could be reliable enough for estimating hydration process in food grains, food packaging films etc.

The Influence of Kaolin Clay on the Mechanical Properties and Structure of Thermoplastic Starch Films

The aim of study was to investigate the influence of kaolin on the physical properties and utility of film produced from native starch. The work involved measurements of strength, structure, and thermal properties. The films were prepared by the casting method. Composite films with 0%, 5%, 10%, and 15% kaolin additives were examined. Measurements of mechanical properties were carried out using the uniaxial tensile test, the nanoindentation test, and nanoscratching. Surface properties were examined by atomic force microscopy and contact angle measurements. Structure was determined by the X-ray diffraction method, and thermal properties were determined by differential scanning calorimetry. A significant influence of kaolin on the strength parameters and thermal and barrier properties of composite films was found. An increase in kaolin content reduced the tensile strength, Young’s modulus, and Poisson’s ratio. Structural analysis showed a partial intercalation and the layered arrangement of kaolin particles. Kaolin additives increased the barrier properties of water vapor in composite films of about 9%. Biopolymer modification by nanoclay reduced the thermal stability of composite films by 7% and could accelerate the biodegradation process. Increasing the concentration of kaolin in the biopolymer matrix led to heightened surface roughness (approximately 64%) and wettability of the surfaces of the film composites of 58%.

Preparation and characterization of inexpensive kaolin hollow fibre membrane (KHFM) prepared using phase inversion/sintering technique for the efficient separation of real oily wastewater

A low-cost kaolin hollow fiber membrane (KHFM) with unique finger-like and sponge-like structures was successfully fabricated by utilizing cheap and abundantly available kaolin clay as the starting material via phase inversion/sintering technique. In this study, mixing kaolin particles prepare the ceramic suspension, dispersant, polymer binder, and solvent using a planetary ball mill. This process is then followed by extrusion at various kaolin contents, bore fluid flow rates, and sintering temperatures ranging from 1200 to 1500 °C. The effect of calcium carbonate (CaCO3) content and polyethylene glycol (PEG) molecular weight as a function of pore agents are also discussed. Membrane characterizations were performed in terms of morphology, pore size distribution, porosity, mechanical strength, contact angle value, and pure water flux. The performance of membranes towards oil-in-water separation was conducted using oily wastewater samples taken from three points in Johor, Malaysia which were Kluang Oil Palm Mill Sdn. Bhd. in Kluang district, a car wash in Taman Skudai Baru in Johor Bahru district, and Meranti café, Universiti Teknologi Malaysia (UTM). The optimum parameters in fabricating the inexpensive KHFM were identified. It was found that the increase of kaolin content, bore fluid flow rate, and sintering temperature gave insignificant effect in the formation of finger–like structure but the process can be used to find a defect-free (i.e., rounded lumen and sufficient thickness) hollow fiber membrane shape. Interestingly, the finger-like structure can be controlled by the addition of PEG as a pore agent at different molecular weights. KHFM prepared with PEG 30,000 as a pore agent offered the highest oil rejection of 99.99% of turbidity and total organic carbon (TOC), and 91.8% of chemical oxygen demand (COD) with stable high flux of 320 L/m2h for all oily wastewater samples.

Effect of Kaolinite on the Mechanical Properties, Thermal Properties, Flammability and Water Absorption Percentage of Poly (Vinyl Chloride) Composite

PVC/Kaolinite composites were prepared by the melt intercalation method. Mechanical properties, thermal properties, flammability and water absorption percentage of prepared samples were tested. Mechanical characteristic such as tensile strength, elongation at break; hardness and impact strength (charpy type) were measured for all samples. It was found that the tensile strength and elongation at break of PVC composites decreased with increasing kaolinite loading. Also, the hardness of the composites increases with increase in filler content .The impact strength of the composites at the beginning increases at lower kaolinite loadings is due to the lack of kaolin adhesion to the matrix. However, at higher kaolin loadings. This severe agglomeration of the filler due to its high surface energy creates many crack-initiation and stress-concentration sites, which are sensitive to impact stresses and cause detrimental effects on the impact properties of the composite. There is a general increase in absorption rate with increase in kaolin content. Thermal properties of PVC /kaolinite composites were characterized using Differential Scanning Calorimetry (DSC) and thermal conductivity analyzer. The results showed Tg shifted toward higher temperature for kaolinite composites compared to neat PVC .Also, thermal conductivity measurement value and effusivity increased with increasing filler loading .Heat capacity decreased with increasing filler content. The higher the filler content the higher burning time, the lower rate of burning and the lower height of the flame which are evident at 12wt. % for kaolinite.

Rheological Properties of Kaolin/PolyetherSulfone(PESf) Used in Hollow Fiber Fabrication: Effects of Content Ratio

In the present work, the rheological properties in terms of shear stress and viscosity of Kaolin/Polyether-Sulfone (PESf) of varying ratio were investigated by a rotating rheometer. The shear rate of Kaolin/PESf sample was measured at increasing interval shear rate. By assuming that the fluid behaves like a typical Non-newtonian polymeric liquid, the consistency index, K and flow index, n were able to be determined. Thus, the rheology behaviors of the kaolin/PESf suspension could be investigated at a wider range of shear rate. The shear stress was found to increase with increasing shear rate, with the rate of change quite apparent at low shear rate. At higher shear rate, the shear stress increases definitively with the increase of kaolin content. On the other hand, the viscosity decreased at a faster rate initially and slows down to monotonous rate as the shear rate increases. Evidently at increasing shear rate, the viscosity tends to become constant as the deviation become smaller which is also known as zero shear rate viscosity region.

Unsaturated Hydraulic Conductivity of Compacted Sand-Kaolin Mixtures

The unsaturated hydraulic conductivity of compacted sand-kaolin mixtures containing 0, 5, 10, and 30 kaolin (by dry weight) is measured for matric suctions, ψm<∼6.0 m. The measured unsaturated hydraulic conductivity (kmeasured) values are compared with predicted unsaturated hydraulic conductivity (kpredicted) values using the Brooks-Corey-Burdine and van Genuchten-Mualem relative hydraulic conductivity functions. In general, the accuracy of kpredicted decreases with an increase in kaolin content or an increase in ψm. In addition, kmeasured tends to be underpredicted for kaolin contents of 10 and 30 at relatively high suctions (1.0 m ≤ψm≤ 6.0 m) and overpredicted for kaolin contents of 0 and 5 at relatively low suctions (0.1 m ≤ψm< 1.0 m). For a given kaolin content and ψm, kpredicted based on the Brooks-Corey-Burdine function tends to be more accurate than kpredicted based on the van Genuchten-Mualem function. Finally, for 1.0 m ≤ψm≤ 6.0 m, kpredicted based on analysis using the maximum volumetric water content (θm) attained under steady-state flow conditions typically is more accurate than kpredicted based on analysis using the saturated volumetric water content, θs, where θm∼ 84–90 of θs in this study.

Paleoclimatic and structural environment at the end of the Cretaceous along the western flank of the Congo basin, with application of underground microdiamonds around Brazzaville

In Brazzaville (R.P. Congo), the study of outcrops and well sections permitted an investigation of the sedimentary evolution of the Continental Paleoenvironments during the Cretaceous and Tertiary, along a vertical thickness of 70 m (so-called Stanley Pool Formations). The base of the deposits is made of reworked red Precambrian sandstone of Inkisi which is associated with an argillaceous phase with dominant montmorillonite.The late-Cretaceous involved a renewal of erosion which was manifested by the deposition of coarse sands of alluvial-flats where general metamorphic minerals are associated with relatively important evidence of microdiamonds. Climatic changes indicate a more ferralitic pedogenesis of the drainage basins as evident by an increase in kaolin content. Towards the top of the section and the beginning of the Tertiary, kaolin tends to dominate the clay mineral fraction. The metakimberlites of Gabon and the diamond concentrations of Bouenzien at the flank of the granitic massif of Chaillu are considered as possible origins of the microdiamonds.

Effect of Kaolin Addition on Properties of Forsterite Porcelain

The stability of the forsterite porcelian in hydrogen at high temperatures, which is required in the application of the forsterite porcelain to a high frequency insulator, is governed by additives used to promote sintering. Among several additives examined kaolin has the effect to make the porcelain stable in hydrogen at high temperatures, so giving it favorable properties for Mo-Mn metallizing processed under such conditions.In this paper 0-10% of kaolin was added to forsterite porcelains which were prepared from Fukushima siliceous stone and sea-water magnesia in the molar ratio of MgO: SiO2=2:1.By the addition of kaolin the temperature range for sintering was remarkably extended and the firing shrinkage was almost constant within this range. The coefficient of linear thermal expansion decreased with the increase of added kaolin, and no considerable change was found by repeated heat treatments. With the increase of kaolin content from 0 to 10%, the softening temperature under load lowered to 1160°C from 1280°C. The electric resistance at elevated temperatures lowered gradually, but was still sufficiently high for practical use. The flexural strength decreased and the modulus of elasticity lowered gradually in the temperature range from room temperature to 300°C with the increase of kaolin content. The modulus of elasticity, however, became larger with the rise of temperature in this temperature range.Within 5% of kaolin added, the dielectric constant and dielectric loss were unvaried and these values were excellent for the high frequency insulator.The result of X-ray diffraction gave only the pattern of the forsterite. By microscopic observation, forsterite crystal grain changed from allotriomorphic into idiomorphic and glass matrix increased with the kaolin content.It is concluded that the addition of 2.5-5.0% of kaolin was most suitable for preparing the forsterite porcelain for this purpose.