Development of toothpaste formulations containing mineral clays as abrasive agents and their effects on the physical properties of dental enamel.

To assess the physical properties and topographical aspect of dental enamel's surface microhardness (KHN), surface roughness (Ra), and color parameters CIELAB (∆Eab*), CIEDE 2000 (∆E00), and whiteness index for dentistry (∆WID) after toothbrushing with experimental toothpaste formulations with the following mineral clay types: kaolin, Sparclay SGY, and Tersil CGY used as abrasive component. Scanning electron microscopy (SEM) was performed for topographical analyses purposes. A total of 96 bovine incisors were used in the experiment. They were divided into eight experimental groups (n = 12), namely: NC-negative control (no treatment), CT12-Colgate Total 12®, CMP-Colgate® Máxima Proteção Anticáries, K-kaolin experimental toothpaste, SGY-Sparclay SGY experimental toothpaste; CGY-Tersil CGY experimental toothpaste, SD-SiO2 experimental toothpaste, and CC-CaCO3 experimental toothpaste. All samples were subjected to mechanical brushing protocol with 5000 cycles and kept in artificial saliva with daily exchanges. KHN was analyzed through the mixed linear model for repeated measures over time. Ra was analyzed through nonparametric Kruskal Wallis and Dunn tests to compare the groups. Paired Wilcoxon test was run to compare experimental times. ∆WID, ∆Eab*, and ∆E00 were analyzed through Kruskal Wallis and Dunn tests. All analyses were performed in R* software, at 5% significance level. EXP_SGY recorded higher KHN than EXP_SiO2 and EXP_CaCO3, whereas EXP_K showed increased Ra in comparison to CMP (p = 0.0229). ∆Eab and ∆E00 were significantly higher in the CT12, EXP_SiO2, and EXP_CaCO3 groups than in the NC and EXP_K (p < 0.0001). There were no significant changes in ∆WID (p = 0.0852). According to SEM results, toothbrushing with experimental toothpastes added with mineral clay types did not have significant impact on enamel's polishing and smoothness. CLINICAL RELEVANCE: Mineral clays have a broad application in the cosmetic industry, and recently, they have been used in the formulation of vegan toothpaste.

Synergistic adsorption and photocatalytic degradation of tetracycline using a Z-scheme kaolin/g-C3N4/MoO3 nanocomposite: A sustainable approach for water treatment.

This research focuses on the synthesis and application of a novel kaolin-supported g-C3N4/MoO3 nanocomposite for the degradation of tetracycline, an important antibiotic contaminant in water systems. The nanocomposite was prepared through a facile and environmentally friendly approach, leveraging the adsorption and photocatalytic properties of kaolin, g-C3N4 and MoO3 nanoparticles, respectively. Comprehensive characterization of the nanocomposite was conducted using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and optical spectra. The surface parameters were studied using N2 adsorption-desorption isotherm. The elemental composition was studied using X-ray photoelectron spectroscopy. The efficiency of the developed nanocomposite in tetracycline degradation was evaluated and the results revealed an efficient tetracycline degradation exhibiting the synergistic effects of adsorption and photocatalytic degradation in the removal process. The tetracycline degradation was achieved in 60 min. Kinetic studies and thermodynamic analyses provided insights into the degradation mechanism, suggesting potential applications for the nanocomposite in wastewater treatment. Additionally, the recyclability and stability of the nanocomposite were investigated, demonstrating its potential for sustainable and long-term application in water treatment.

Preparation, characterization, and applications of kaolin/kaolin-based composite membranes in oily wastewater treatment: Recent developments, challenges, and opportunities.

Rapid industrialization and the accompanying generation of significant amounts of oily wastewater pose major environmental challenges, which necessitate efficient treatment technologies. Kaolin-based membranes have emerged as a promising option due to their availability, affordability, and effective filtration performance. This review comprehensively analyzes the potential of kaolin for the treatment of oily wastewater. The focus is on the main manufacturing methods such as uniaxial pressing, slip casting, tape casting, phase inversion, and extrusion, as well as modifications that improve the structural integrity of the membrane, and its surface wettability to enhance separation performance. In addition, characterization techniques to evaluate membrane properties such as mechanical strength, thermal and chemical stability, antifouling behavior etc. are discussed. Basically, kaolin can be used as a supporting substrate, as a primary separation layer or as an additive in non-kaolin membranes. In evaluating the oil-water separation performance of kaolin-based membranes, this review highlights important metrics such as oil separation rate, flux, flux recovery, antifouling behavior, and resistance to harsh physical and chemical environments. Articles selected for the review were retrieved from major databases such as EBSCOhost, Scopus, ScienceDirect, Web of Science, and Google Scholar using relevant keywords. Based on the data from these studies, the main advances, challenges, and prospects are highlighted. Although still in the early stages of commercial application, kaolin membranes show significant potential to improve filtration efficiency, mechanical and chemical resistance, and reduce operating costs in industrial oily wastewater treatment systems.

Study of the Preparation and Performance of TiO2-Based Magnetic Regenerative Adsorbent.

Against the backdrop of "carbon neutrality", the green treatment of dye wastewater is particularly important. Currently, the adsorption method shows strong application prospects. Therefore, selecting efficient and recyclable adsorbents is of significant importance. TiO2 is an excellent adsorbent, but its difficult recovery often leads to secondary pollution. γ-Fe2O3-modified coal-series kaolin exhibits both excellent adsorption properties and rapid separation through magnetic separation technology. By utilizing the synergistic effects of both, TiO2/-γFe2O3 coal-series kaolin, magnetic adsorbent regeneration materials were prepared using coprecipitation method and characterized. The influencing factors of this functional material on the adsorption of Congo red dye and its regeneration performance are discussed. The experimental results indicated that the specific surface area, pore volume and Ms value of this functional material are 127.5 m2/g, 0.38 cm3/g, and 13.4 emu/g, respectively. It exhibits excellent adsorption characteristics towards Congo red, with an adsorption rate reaching 96.8% within 10 min, conforming to the pseudo-second-order kinetic model, and demonstrating Langmuir IV-type monolayer adsorption. After the adsorption of Congo red, magnetic separation shows superior efficiency. Furthermore, treatment of the adsorbed composite with EDTA allows for recycling, with adsorption rates still above 91% after three cycles, indicating an excellent regeneration capability.

Simultaneous Inhibition of Vanadium Dissolution and Zinc Dendrites by Mineral-Derived Solid-State Electrolyte for High-Performance Zinc Metal Batteries.

Designing solid electrolyte is deemed as an effective approach to suppress the side reaction of zinc anode and active material dissolution of cathodes in liquid electrolytes for zinc metal batteries (ZMBs). Herein, kaolin is comprehensively investigated as raw material to prepare solid electrolyte (KL-Zn) for ZMBs. As demonstrated, KL-Zn electrolyte is an excellent electronic insulator and zinc ionic conductor, which presents wide voltage window of 2.73 V, high ionic conductivity of 5.08 mS cm-1, and high Zn2+ transference number of 0.79. For the Zn//Zn cells, superior cyclic stability lasting for 2200 h can be achieved at 0.2 mA cm-2. For the Zn//NH4V4O10 batteries, stable capacity of 245.8 mAh g-1 can be maintained at 0.2 A g-1 after 200 cycles along with high retention ratio of 81 %, manifesting KL-Zn electrolyte contributes to stabilize the crystal structure of NH4V4O10 cathode. These satisfying performances can be attributed to the enlarged interlayer spacing, zinc (de)solvation-free mechanism and fast diffusion kinetics of KL-Zn electrolyte, availably guaranteeing uniform zinc deposition for zinc anode and reversible zinc (de)intercalation for NH4V4O10 cathode. Additionally, this work also verifies the application possibility of KL-Zn electrolyte for Zn//MnO2 batteries and Zn//I2 batteries, suggesting the universality of mineral-based solid electrolyte.

Stabilizing Cr(â ¢) deriving from tannery sludge with kaolin and organic matter.

Stabilizing Cr(III) in tannery sludge (TS) via harmless method has always been the goal of environmental pollution treatment. In this study, a simple method to stabilize Cr(III) in TS is proposed via adding kaolin, based on the fact a large amount of organic matter contained in TS. Comprehensive characterizations confirm that kaolin can stabilize Cr(Ⅲ) via its abundant -OH and lamellar structure. Moreover, there are hydrogen bond interactions and ligand exchange-surface complexation between organic matter and kaolin, which is more conducive to form a stable ternary complex with Cr(III), in a state of organic matter-Cr(III)-kaolin. Simultaneously, the BCR sequential extraction experiment shows that the unstable water and acid soluble state of Cr(III) are reduced (from 0.61% to 0.35%), which further indicates that the stabilization of Cr(III) is successful.

Impact of Bacillus species on Fe reduction of kaolin in bioleaching: surface, structural, and chemical studies.

Conventional techniques to remove Fe impurities in kaolin typically involve high environmental impact and cost. Alternative methods have been focused on the use of bioleaching where Fe in kaolin is reduced with microorganisms. Early results established a noticeable effect of the bacteria on the redox state of Fe, but knowledge gaps persist such as details on the bacterial-kaolin interactions during attachment of bacteria onto kaolin surface, the metabolites produced by bacteria, and changes in Fe(II)/Fe(III) ion equilibria in solution. To bridge these gaps, this study was conducted to determine the detailed physicochemical changes in bacteria and kaolin during bioleaching through surface, structural, and chemical analysis. Bioleaching experiments were conducted for 10 days where each of the three Bacillus sp. was put in contact (at 9 × 108 CFU) with 20 g of kaolin powder using 200 mL of 10 g/L glucose solution. All samples treated with bacteria showed increasing trends in Fe(III) reduction up until day 6 or 8 followed by a slight decrease towards the end of the ten-day period. Examination of scanning electron microscope (SEM) images suggests that bacterial activity damaged the edges of kaolin particles during bioleaching. Ion chromatography (IC) results showed that during bioleaching, Bacillus sp. produced organic acids such as lactic acid, formic acid, malic acid, acetic acid, and succinic acid. EDS analysis of kaolin before and after bioleaching showed Fe removal efficiencies of up to 65.3%. Analyses of color properties of kaolin before and after bioleaching showed an improvement in whiteness index of up to 13.6%. KEY POINTS: • Dissolution of iron oxides by Bacillus species proven with phenanthroline analysis. • Organic acid type and concentration unique to species detected during bioleaching. • Whiteness index of kaolin is improved after bioleaching.

Interference of tritrophic (grape × medfly × parasitoid) interactions by mineral and biomaterial films.

Fruit fly infestation is one of the main obstacles to the exportation of fresh agricultural produce. Films of mineral particles and biomaterials have the potential to protect fruits against tephritid fruit fly infestation. The present study evaluated the effects of particle films on the tritrophic interactions of grape (Vitis vinifera L.), the fruit fly Ceratitis capitata (Wiedemann) and the parasitoid Diachasmimorpha longicaudata (Ashmead) under semi-field conditions. Grapes were biometrically characterised (i.e. colour, firmness, mass, length and diameter), treated with mineral particles, biomaterials or distilled water (control), and then used in oviposition and parasitism bioassays. In the oviposition bioassay, the treated grapes were exposed to 50 C. capitata pairs in field cages, and after 48 h, the punctures and eggs on each fruit were counted. In the parasitism bioassay, treated grapes were artificially infested with third-instar C. capitata larvae (two per fruit), exposed (2 h) to 50 D. longicaudata pairs in field cages to determine parasitism index, larval and pupal viabilities and number of flies and parasitoids emerged. Treatment with the mineral film affected fruit colour and reduced C. capitata oviposition but failed to significantly affect the parasitism capacity of D. longicaudata. The ability of the parasitoid to locate and parasitise C. capitata larvae in kaolin-coated fruits suggests that kaolin films could be used in conjunction with biological agents to control fruit flies.

Experimental Analysis of Various Blockage Performance for LiDAR Sensor Cleaning Evaluation.

Autonomous driving includes recognition, judgment, and control technologies, and is implemented using sensors such as cameras, LiDAR, and radar. However, recognition sensors are exposed to the outside environment and their performance may deteriorate because of the presence of substances that interfere with vision, such as dust, bird droppings, and insects, during operation. Research on sensor cleaning technology to solve this performance degradation has been limited. This study used various types and concentrations of blockage and dryness to demonstrate approaches to the evaluation of cleaning rates for selected conditions that afford satisfactory results. To determine the effectiveness of washing, the study used the following criteria: washer, 0.5 bar/s and air, 2 bar/s, with 3.5 g being used three times to test the LiDAR window. The study found that blockage, concentration, and dryness are the most important factors, and in that order. Additionally, the study compared new forms of blockage, such as those caused by dust, bird droppings, and insects, with standard dust that was used as a control to evaluate the performance of the new blockage types. The results of this study can be used to conduct various sensor cleaning tests and ensure their reliability and economic feasibility.

A novel combined metallurgy-beneficiation method for the facile and low-cost comprehensive resource utilization of low-grade kaolin solid wastes.

Low-grade kaolin is the largest emissions of industrial solid waste that is difficult to dispose of and pollutes the environment seriously. From the perspective of harmless and complete resource utilization, we proposed a novel strategy that combines the wet leaching under mild conditions and physical beneficiation for the facile and low-cost high-valued utilization of low-grade kaolin that involves high-efficiency recovery of aluminum (Al), silicon (Si), and titanium (Ti). The key to successful implementation of this method lies in the new discovery that the residual SiO2 after Al extraction of kaolinite by acid leaching under specific conditions could be rapidly dissolved in dilute NaOH solution at room temperature 25 °C. This highly reactive SiO2 challenges the conventional notions of various silica species are usually chemically stable. By adjusting the key technical parameters of the thermal activation-acid leaching process, the selective and efficient extraction of Al2O3 from low-grade kaolin was realized. The acid leaching residue was then subjected to selective recovery of SiO2 by alkaline leaching at 25 °C to obtain high-quality sodium silicate. Finally, the alkali leaching residue as titanium coarse concentrate was separated by centrifugal concentrator to obtain artificial rutile (TiO2 >91.06%). The key mechanism for the formation of the highly reactive silica was also systematically studied and confirmed.

Local Clays from China as Alternative Hemostatic Agents.

In recent years, the coagulation properties of inorganic minerals such as kaolin and zeolite have been demonstrated. This study aimed to assess the hemostatic properties of three local clays from China: natural kaolin from Hainan, natural halloysite from Yunnan, and zeolite synthesized by our group. The physical and chemical properties, blood coagulation performance, and cell biocompatibility of the three materials were tested. The studied materials were characterized by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). All three clays showed different morphologies and particle size, and exhibited negative potentials between pH 6 and 8. The TGA and DSC curves for kaolin and halloysite were highly similar. Kaolin showed the highest water absorption capacity (approximately 93.8% ± 0.8%). All three clays were noncytotoxic toward L929 mouse fibroblasts. Kaolin and halloysite showed blood coagulation effects similar to that exhibited by zeolite, indicating that kaolin and halloysite are promising alternative hemostatic materials.

An Investigation of a Natural Biosorbent for Removing Methylene Blue Dye from Aqueous Solution.

T he current study reports the use of zeolite prepared from a kaolin composite via physical mixing with different ratios from fiber of palm tree (Zeo-FPT) as a sustainable solid sorbent for the removal of methylene blue (MB) dye from aqueous solutions. The prepared biosorbent was fully characterized using XRD, TGA, SEM, and FTIR. The impacts of various analytical parameters, for example, contact time, dosage, MB dye concentration, and the pH of the solution, on the dye adsorption process were determined. After a contact time of 40 min, the capacity to remove MB dye was 0.438 mg g-1 at a Zeo-FPT composition ratio of 1F:1Z. At pH 8, Zeo-FPT (1F:1Z) had a removal efficiency of 87% at a sorbent dosage of 0.5 g for a concentration of MB dye in an aqueous phase of 10 mg L-1. The experimental data were also analyzed using the kinetic and adsorption isotherm models. The retention process fitted well with the pseudo-second-order model (R2 0.998), where the Qe,calc of 0.353 mg g-1 was in acceptable agreement with the Qe,exp of 0.438 mg g-1. The data also fitted well with the Freundlich isotherm model, as indicated by the correlation coefficient value (R2 0.969). The Zeo-FPT attained a high percentage (99%) in the removal of MB dye from environmental water samples (tap water, bottled water, and well water). Thus, it can be concluded that the proposed zeolite composite with fiber of palm tree (Zeo-FPT) is a suitable, environmentally friendly, and low-cost adsorbent for removing dyes from wastewater.

Effect of clay supplementation on growth performance of broiler chickens: a systematic review and meta-analysis.

1. This review assessed the effect of dietary clay supplementation as a drug and toxin adsorbent on broiler growth performance as a meta-analysis.2. A total of 33 eligible studies were included in the present study after identification and evaluation from online databases. Standardised mean differences (SMD) with corresponding 95% confidence intervals were computed with a fixed-effects model.3. The results indicated that clay supplementation significantly improved broiler daily gain (P < 0.001) and feed conversion ratio (P < 0.001), but did not affect feed intake (P = 0.954). Results of subgroup analysis showed that zeolite clay had the most stable medium improvement effect on FCR, while kaolin had a large effect. In addition, male broilers and Cobb or Ross broilers were more sensitive to the addition of clay, and the best supplemental levels, in general, were 10 g/kg to 30 g/kg.4. Meta-regression analysis showed that clay supplemental level and sex of broilers may be important factors in the effect of clay on ADG and FCR of broilers, respectively. The sensitivity analysis showed high stability of the results and no significant publication bias was found with funnel plot analysis and Egger's or Begg's test (P > 0.05).5. In conclusion, an appropriate addition level is a prerequisite for effective clay application. Kaolin and zeolite clays seem to be more suitable for enhancing broiler growth performance, and the value of clay is amplified in specific broiler breeds.

Intracranial pressure and optic disc changes in a rat model of obstructive hydrocephalus.

BACKGROUND: The kaolin induced obstructive hydrocephalus (OHC) model is well known for its ability to increase intracranial pressure (ICP) in experimental animals. Papilledema (PE) which is a predominant hallmark of elevated ICP in the clinic has not yet been studied in this model using high-resolution digital fundus microscopy. Further, the long-term effect on ICP and optic nerve head changes have not been fully demonstrated. In this study we aimed to monitor epidural ICP after induction of OHC and to examine changes in the optic disc. In addition, we validated epidural ICP to intraventricular ICP in this disease model. METHOD: Thirteen male Sprague-Dawley rats received an injection into the cisterna magna containing either kaolin-Ringer's lactate suspension (n = 8) or an equal amount of Ringer's lactate solution (n = 5). Epidural ICP was recorded post-operatively, and then continuously overnight and followed up after 1 week. The final epidural ICP value after 1 week was confirmed with simultaneous ventricular ICP measurement. Optic disc photos (ODP) were obtained preoperatively at baseline and after one week and were assessed for papilledema. RESULTS: All animals injected with kaolin developed OHC and had significant higher epidural ICP (15.49 ± 2.47 mmHg) compared to control animals (5.81 ± 1.33 mmHg) on day 1 (p < 0.0001). After 1 week, the epidural ICP values were subsided to normal range in hydrocephalus animals and there was no significant difference in epidural ICP between the groups. Epidural ICP after 1 week correlated with the ventricular ICP with a Pearson's r = 0.89 (p < 0.0001). ODPs from both groups showed no signs of acute papilledema, but 5 out of 8 (62.5%) of the hydrocephalus animals were identified with peripapillary changes. CONCLUSIONS: We demonstrated that the raised ICP at day 1 in the hydrocephalus animals was completely normalized within 1 week and that epidural ICP measurements are valid method in this model. No acute papilledema was identified in the hydrocephalus animals, but the peripapillary changes indicate a potential gliosis formation or an early state of a growing papilledema in the context of lateral ventricle dilation and increased ICP.

Kaolin-graphene carboxyl incorporated TiO2 as efficient visible light active photocatalyst for the degradation of cefuroxime sodium.

A novel solar light active photocatalyst, TiO2/kaolin-graphene carboxyl nanocomposite was synthesized by hydrothermal method for the degradation of cephalosporin antibiotic, cefuroxime sodium. The synthesized photocatalyst was characterized by various analytical and spectroscopic techniques, including Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) thermogravimetry (TG), UV-Vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL). The prepared TiO2/kaolin-graphene carboxyl nanocomposite exhibited efficient photocatalytic degradation of methylene blue (MB) upon illumination with the solar simulator as compared to unmodified TiO2. The incorporation of both kaolin and graphene carboxyl was found to immobilize TiO2, enhancing the visible light absorption range of TiO2. Scavenger study revealed that hydroxyl radicals act as the main active species in the photocatalytic degradation process. The hydroxyl group present on kaolin surface reacts with photo-generated holes to increase the amount of hydroxyl radical, and further the graphene carboxyl plays a role to impede the recombination of photo-generated electron-hole pairs. Furthermore, the synthesized photocatalyst was found to degrade cefuroxime sodium within 90 min of sunlight illumination, indicating that TiO2/kaolin-graphene carboxyl nanocomposites would be very beneficial for pharmaceutical waste management through the advanced oxidation process. Mass spectral analysis was also carried out for elucidating the photocatalytic degradation pathway of cefuroxime sodium.

Cellulase immobilized on kaolin as a potential approach to improve the quality of knitted fabric.

Biopolishing is a textile process that uses cellulases to improve the pilling resistance of fabrics. Although the process improves the pilling resistance, softness and color brightness of fabrics, it causes a significant loss of tensile strength in treated fabrics. The present work studied the use of cellulase immobilized on kaolin by adsorption and covalent bonding in biopolishing to get around this problem. The cellulase immobilization has been reported as promising alternative to overcome the inconvenient of biopolishing, but it has been very poorly explored. The results showed that cellulase immobilized by both covalent bonding and adsorption methods provided to the knitted fabric similar or superior pilling resistance to free cellulase, but with greater tensile strength. Immobilization also allowed for efficient recovery and reuse of the enzyme. The present work is a relevant contribution to the literature, since, as far as we know, it is the first work that shows it is possible to minimize the loss of tensile strength and also reuse the immobilized enzyme, giving a better-quality product and also contribution to reducing the cost of the polishing step.

Plate Load Tests on an Unsaturated Sand-Kaolin Mixture with Varying Water Table.

Clayey sand is widely distributed and commonly encountered in geotechnical engineering practice. To understand its bearing capacity behavior under unsaturated conditions, plate load tests are performed on sand-kaolin mixture samples with varying water tables. The distributions of suction and volumetric water content with depth are measured by vibrating wire piezometers and soil moisture sensors, respectively. It is shown by the test results that the bearing capacity increases when the water table in the soil sample drops. The influence of suction on the bearing capacity is found to be dependent on the height of the water table and the hydraulic loading history of the soil sample. The plate load test results are interpreted using bearing capacity equations. Good agreement is obtained between measured and calculated bearing capacities. This study provides a simple method to estimate the bearing capacity of in situ unsaturated soil foundations.

Evaluation of the Properties of PHB Composite Filled with Kaolin Particles for 3D Printing Applications Using the Design of Experiment.

In the presented work, poly(3-hydroxybutyrate)-PHB-based composites for 3D printing as bio-sourced and biodegradable alternatives to synthetic plastics are characterized. The PHB matrix was modified by polylactide (PLA) and plasticized by tributyl citrate. Kaolin particles were used as a filler. The mathematical method "Design of Experiment" (DoE) was used to create a matrix of samples for further evaluation. Firstly, the optimal printing temperature of the first and upper layers was determined. Secondly, the 3D printed samples were tested with regards to the warping during the 3D printing. Testing specimens were prepared using the determined optimal printing conditions to measure the tensile properties, impact strength, and heat deflection temperature (HDT) of the samples. The results describe the effect of adding individual components (PHB, PLA, plasticizer, and filler) in the prepared composite sample on the resulting material properties. Two composite samples were prepared based on the theoretical results of DoE (one with the maximum printability and one with the maximum HDT) to compare them with the real data measured. The tests of these two composite samples showed 25% lower warping and 8.9% higher HDT than was expected by the theory.

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.

Preparation of Chitosan/Clay Composites for Safe and Effective Hemorrhage Control.

Uncontrolled hemorrhage from trauma or surgery can lead to death. In this study, chitosan/kaolin (CSK) and chitosan/montmorillonite (CSMMT) composites were prepared from chitosan (CS), kaolin (K), and montmorillonite (MMT) as raw materials to control bleeding. The physiochemical properties and surface morphology of CSK and CSMMT composites were analyzed by Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta potentials, and X-ray fluorescence (XRF). The hemostatic mechanism was measured in vitro by activated partial thromboplastin time (APTT), prothrombin time (PT), in vitro clotting time, erythrocyte aggregation, and thromboelastogram (TEG). The hemostasis ability was further verified by using tail amputation and arteriovenous injury models in rats. The biocompatibility of CSK and CSMMT was evaluated by in vitro hemolysis, cytotoxicity assays, as well as acute toxicity test and skin irritation tests. The results show that CSK and CSMMT are promising composite materials with excellent biocompatibility and hemostatic properties that can effectively control bleeding.