Microwave absorber utilization to improve grinding and particle surface structure characteristics of torrefied switchgrass particles for bioenergy applications.

Torrefaction treatment improves biomass grindability by transforming the fibrous herbaceous to a more brittle and lighter coal-like material. Microwave-assisted torrefaction is a promising technology for biomass conversion into energy, fuels, and chemicals. The study applied microwave absorbers in the torrefaction process to improve the thermochemical characteristics and grindability of switchgrass. Switchgrass in two particle sizes was torrefied in a microwave reactor with biochar added as a microwave absorber under inert conditions. After torrefaction, the geometric mean particle and size distribution and selected physical characteristics were evaluated, and the grindability of the torrefied ground and chopped with and without biochar were compared with those of untreated switchgrass. The geometric diameter results decreased, and the specific energy required for grinding torrefied switchgrass with biochar was significantly reduced with extended residence times and at a torrefaction temperature of 300 °C. After grinding, the lowest grinding energy of 32.82 kJ at 300 °C/20 min was recorded with torrefied ground switchgrass/biochar. The 10% biochar added/250 °C resulted in deep cell wall disarrangement, whereas at a torrefaction temperature of 300 °C, large surface deformation and carbonized weight fractions were observed.

Impact of particle size of cereals and soyabean meal on the intestinal development of weanling pigs and growth performance after an enteric challenge with F4-positive enterotoxigenic E. coli.

The objectives were to determine the interactive effect of particle size of soyabean meal (SBM) and whole wheat, barley and wheat bran (CER) on growth performance of weanling pigs after an enterotoxigenic Escherichia coli F4 challenge (Experiment 1) and on gastrointestinal (GIT) development immediately after weaning (Experiment 2). Experiment 1 consisted of 192 pigs (24 ± 3 days of age; 7.4 ± 1.1 kg weaning bodyweight [BW]) selected for Escherichia coli (E. coli) F4 susceptibility. Pigs were given an oral E. coli inoculum at postweaning day 7, to induce an enteric health challenge. Experiment 2 consisted of 40 pigs (24 ± 3 days of age; 7.2 ± 1.0 kg weaning BW) that were killed on postweaning day 8 or 9, to determine the effects of particle size on GIT development and functionality. Four experimental diets were used in a 2 × 2 factorial design: (1) coarse CER and coarse SBM, (2) coarse CER and fine SBM (CERcSBMf), (3) fine CER and coarse SBM, or (4) fine CER and fine SBM (CERfSBMf). Results showed no interaction between SBM and CER coarseness on growth performance, GIT development and functionality. Diarrhoea incidence was higher (p < 0.05) for CERfSBMf during the 2 weeks following the E. coli challenge compared to the other diets. Daily gain and feed intake during this period were higher (p < 0.05) for pigs fed CERc compared to CERf. Empty stomach weight tended to be greater by 8% (p = 0.09) for CERc compared to CERf. Gastric protein (p = 0.05) and starch (p = 0.04) disappearances were greater for SBMf compared to SBMc. Thus, CERcSBMf resulted in the best growth performance and lowest diarrhoea incidence during the 2 weeks following the E. coli challenge, which may be explained by changes in stomach functionality but not by changes in other parts of the GIT.

Influence mechanism of grinding surface quality of 20CrMnTi steel on contact failure.

To reveal the influence mechanism of the grinding surface quality of 20CrMnTi steel components on the tribological characteristics and contact fatigue performance, accelerated tests for sliding friction wear and fatigue damage were carried out. Tribological characteristics and contact fatigue performance get worse with increasing surface roughness while getting better with increasing surface microhardness. Residual compressive stress is conducive to inhibiting the initiation and propagation of cracks and promoting contact fatigue performance. Additionally, mechanical friction, abrasive wear, adhesive wear and fatigue damage coexist and form a competing failure mechanism under the synergistic effect of frictional wear and contact fatigue failure. The damage process mainly manifests as wear, stress concentration induced fatigue, microcracks, pitting, and spalling in the shallow layer. This study is more beneficial to promote the 20CrMnTi steel transmission parts manufacturing products for high precision, low damage, and long life.

The Influence of the Grinding Media Diameter on Grinding Efficiency in a Vibratory Ball Mill.

The grinding process plays a crucial role in industry, allowing for the reduction of particle sizes of raw materials and substances to the required fineness-either as a finished product or for further technological processes. The high demand for micro- and nanopowders or suspensions is associated with the high energy consumption of the milling process. Therefore, optimizing the milling process, including correctly selecting grinding media, is essential to reduce energy consumption. This article presents experimental studies of the grinding process of a model material (quartz sand) in a laboratory vibratory mill. Five sets of grinding media with different diameters were used in the research, and grinding was conducted for various durations. The studies showed that the vibratory grinding process is efficient for each set of grinding media and grinding durations. The research has shown that conducting studies on the proper selection of mills is beneficial, especially regarding very fine grinding of various materials. The study confirmed that properly selecting grinding media sets can significantly accelerate the grinding process. For the selected technological variant, it was demonstrated that using 15 mm grinding media, compared to 12 mm, resulted in a 22.5% reduction in grinding time to achieve a specified particle size class of 0-10 µm.

Preparation and Performance Study of SiC-Reinforced Fe-Based Wear-Resistant Composite Grinding Media.

During industrial and laboratory processes involving material grinding, the grinding media endure prolonged high-collision and friction environments, resulting in substantial wear. Consequently, this study adopts the hot-pressing sintering technique in powder metallurgy to prepare SiC-reinforced Fe-based wear-resistant composite grinding media, aiming to increase wear performance. For this purpose, Fe with 10 wt% SiC powders were milled for the fabrication of the composite. Then, sintering was performed by hot press at 1100 °C in a furnace. Scanning electron microscopy (SEM) and X-ray diffraction were employed to investigate the microstructures and phase of SiC-reinforced Fe-based matrix composite. Subsequently, comparative performance evaluations of the newly developed grinding media and traditional chromium-based media were conducted in terms of wear rate and grinding efficiency. The wear resistance tests revealed that the SiC-reinforced composite media displayed significantly superior wear resistance across various abrasives compared to the chromium-containing alternatives. Specifically, the composite media achieved a wear rate reduction of 2.9 times against standard sand over 1 h, and 2.3 and 2.4 times against sandstone and iron slag, respectively. Moreover, extended grinding for 3 hours further enhanced these reductions to 3.1, 2.4, and 2.7 times, respectively. Additionally, efficiency assessments indicated that at a 1:1 material ratio, the composite media outperformed the chromium-containing media in grinding efficiency by 7.5%, 12.5%, and 10.3% for standard sand, sandstone, and iron slag, respectively. Further increasing the material ratio to 3:1 resulted in efficiency improvements of 7.4%, 17.5%, and 11.3%, correspondingly.

Effect of Wet Grinding Concrete Slurry Waste on Hydration and Hardening Properties of Cement: Micro-Nano-Scale Modification.

The concrete slurry waste (CSW) produced by concrete mixing plants is a type of hazardous waste that is difficult to handle. To better recycle the CSW separated from the aggregates, this study uses a variety of wet-grinding processes to refine the solid in it, replaces some of the cement with the solid particles in wet grinding concrete slurry waste (WCSW), and investigates the properties of WCSW and its effect on the hydration and hardening properties of cement. The results show that a suitable wet-grinding process can ensure that the particle size in WCSW is less than 10 µm, the particle morphology is more flat, and the degree of hydration is higher. The WCSW particles can promote early cement hydration; after adding WCSW, the heat release peak of cement hydration appears earlier and more early hydration products are produced, and with the increase in the substitution amount, the promoting effect on early cement hydration will be more significant. The WCSW particles have a great effect on improving the strength of mortar, especially in the early stage. At 1 d, when the substitution amount is 7.5 wt.%, the compressive and flexural strength is increased by 43.67% and 45.04%; this is related to the filling of matrix pores and the improvement of the interface transition zone by micro- and nanoparticles. After the wet grinding of CSW, fine WCSW particles are obtained, which can improve the performance of cement-based materials by replacing cement.

Experimental Studies of the Machinability of SiCp/Al with Different Volume Fractions under Ultrasonic-Assisted Grinding.

High-volume fraction silicon carbide particle-reinforced aluminum (SiCp/Al) has a promising application for its high specific strength, wear resistance, and thermal conductivity. However, SiCp/Al components with a high-volume fraction are prone to poor surface quality and defects such as fractures, cracks, and micro-pits. It has been reported that ultrasonic-assisted grinding machining (UAG) helps to improve the quality of SiCp/Al machined surfaces. However, the differences between SiCp/Al with different volume fractions obtained by UAG machining are not clear. Therefore, a comparative study of surface roughness, morphology, and cutting force was carried out by UAG machining on SiCp/Al samples with volume fractions of 45% and 60%. Compared to the 45% volume fraction SiCp/Al, the 60% volume fraction SiCp/Al has a higher cutting force and roughness under the same machining parameters. In addition, experiments have shown that cutting forces and surface roughness can be reduced by increasing the tool speed or decreasing the feed rate. UAG machining with an ultrasonic amplitude within 4 µm can also reduce cutting forces and surface roughness. However, more than 6 µm ultrasonic amplitude may lead to an increase in roughness. This study contributes to reasonable parameter settings in ultrasonically-assisted grinding of SiCp/Al with different volume fractions.

Production and comparison of structural, thermal and physical characteristics of chitin nanoparticles obtained by different methods.

This study examined the impact of acid hydrolysis, tempo oxidation, and mechanical grinding on the physical, thermal, and structural properties of α-chitin nanocrystals and nanofibers. The manufacturing methods could influence the diameter, functional groups, and crystal patterns of the resulting nanoparticles. Analysis of the DLS results revealed that the size of acidic nanocrystals were smaller and showed improved dispersibility. The XRD patterns indicated that the chemical and mechanical treatments did not alter the crystalline arrangement of the α-chitin. FT-IR spectra analysis revealed that the chemical and mechanical methods did not affect the functional groups of the nanoparticles. DSC results showed that the nanoparticles had good thermal stability up to 400 °C, and it was found that the nanofibers had better thermal resistance due to their longer length. In the FE-SEM images, the nanoparticles were observed as fiber mats with a length of more than 100 nm. It was also found that the diameter of the nanoparticles was less than 100 nm.

Brittle-Ductile Threshold in Lithium Disilicate under Sharp Sliding Contact.

Computer-aided design (CAD)/computer-aided manufacturing (CAM) milling and handpiece grinding are critical procedures in the fabrication and adjustment of ceramic dental restorations. However, due to the formation of microfractures, these procedures are detrimental to the strength of ceramics. This study analyzes the damage associated with current brittle-regime grinding and presents a potential remedy in the application of a safer yet still efficient grinding regime known as "ductile-regime grinding." Disc-shaped specimens of a lithium disilicate glass-ceramic material (IPS e.max CAD) were obtained by cutting and crystallizing the lithium metasilicate CAD/CAM blanks (the so-called blue blocks) following the manufacturer's instructions. The discs were then polished to a 1 µm diamond suspension finish. Single-particle micro-scratch tests (n = 10) with a conical diamond indenter were conducted to reproduce basic modes of deformation and fracture. Key parameters such as coefficient of friction and penetration depth were recorded as a function of scratch load. Further, biaxial flexure strength tests (n = 6) were performed after applying various scratch loads to analyze their effects on ceramic strength. Scanning electron microscopy (SEM) and focused ion beam (FIB) were used to characterize surface and subsurface damage. Statistical analysis was performed using one-way analysis of variance and Tukey tests. While the SEM surface analysis of scratch tracks revealed the occurrence of both ductile and brittle removal modes, it failed to accurately determine the threshold load for the brittle-ductile transition. The threshold load for brittle-ductile transition was determined to be 70 mN based on FIB subsurface damage analyses in conjunction with strength degradation studies. Below 70 mN, the specimens exhibited neither strength degradation nor the formation of subsurface cracks. Determination of the brittle-ductile thresholds is significant because it sets a foundation for future research on the feasibility of implementing ductile-regime milling/grinding protocols for fabricating damage-free ceramic dental restorations.

Material Removal Mechanism of SiC Ceramic by Porous Diamond Grinding Wheel Using Discrete Element Simulation.

SiC ceramics are typically hard and brittle materials. Serious surface/subsurface damage occurs during the grinding process due to the poor self-sharpening ability of monocrystalline diamond grits. Nevertheless, recent findings have demonstrated that porous diamond grits can achieve high-efficiency and low-damage machining. However, research on the removal mechanism of porous diamond grit while grinding SiC ceramic materials is still in the bottleneck stage. A discrete element simulation model of the porous diamond grit while grinding SiC ceramics was established to optimize the grinding parameters (e.g., grinding wheel speed, undeformed chip thickness) and pore parameters (e.g., cutting edge density) of the porous diamond grit. The influence of these above parameters on the removal and damage of SiC ceramics was explored from a microscopic perspective, comparing with monocrystalline diamond grit. The results show that porous diamond grits cause less damage to SiC ceramics and have better grinding performance than monocrystalline diamond grits. In addition, the optimal cutting edge density and undeformed chip thickness should be controlled at 1-3 and 1-2 um, respectively, and the grinding wheel speed should be greater than 80 m/s. The research results lay a scientific foundation for the efficient and low-damage grinding of hard and brittle materials represented by SiC ceramics, exhibiting theoretical significance and practical value.

A Three-Dimensional Assessment of a Type I Shallow Palatogingival Groove by Cone Beam Computed Tomography: A Case Report.

The palatogingival groove is a developmental anomaly on the palatal surface of the maxillary anterior teeth. The shallow groove, often less than 1 mm, is challenging to diagnose, particularly in radiographic examinations. Such grooves are mistaken for root fractures. In this case study, we explore the prevalence, types, radiological appearances, and treatment options of type I shallow palatogingival grooves encountered in cone beam computed tomography.

Constant force grinding controller for robots based on SAC optimal parameter finding algorithm.

Since conventional PID (Proportional-Integral-Derivative) controllers hardly control the robot to stabilize for constant force grinding under changing environmental conditions, it is necessary to add a compensation term to conventional PID controllers. An optimal parameter finding algorithm based on SAC (Soft-Actor-Critic) is proposed to solve the problem that the compensation term parameters are difficult to obtain, including training state action and normalization preprocessing, reward function design, and targeted deep neural network design. The algorithm is used to find the optimal controller compensation term parameters and applied to the PID controller to complete the compensation through the inverse kinematics of the robot to achieve constant force grinding control. To verify the algorithm's feasibility, a simulation model of a grinding robot with sensible force information is established, and the simulation results show that the controller trained with the algorithm can achieve constant force grinding of the robot. Finally, the robot constant force grinding experimental system platform is built for testing, which verifies the control effect of the optimal parameter finding algorithm on the robot constant force grinding and has specific environmental adaptability.

Comprehension of drying kinetics and stone milling process of chestnuts: a focus on moisture content, milling speed, and energy evaluation.

BACKGROUND: Chestnut flour plays an important role in the production of bread, bakery products, and gluten-free foods. Most of the references in the literature focus on the drying process itself and not on the effects of the drying and milling processes. Moreover, the literature is lacking recommendations regarding optimal moisture content and milling speed, thus motivating the present study. The first aim is to understand the chestnut drying process through an in-depth evaluation of drying kinetics; the second aim is to assess the effects of three different moisture content (2%, 4% and 6%) and three different stone rotational speeds (120, 220 and 320 rpm) on operative milling parameters (flour yield, milling time, energy consumption, temperature increase, average power, specific milling energy), flour particle size distribution, and chestnut flours characteristics. RESULTS: The results show that moisture content and stone rotational speed have statistically-significant effects on milling operative parameters, flour particle size and chestnut flour composition. In particular, stone rotational speed affected almost all the tested variables (mill operative parameters, flour particle size distribution, and flour characteristics). Therefore, as the stone rotational speed increases, energy consumption, average power, specific energy, and damaged starch content significantly increase. CONCLUSION: These findings clearly show that moisture content and stone rotational speed are powerful tools that allow the exploiation of the milling process to modulate the characteristics of the obtained flours. In conclusion, two different approaches for chestnut milling were suggested depending on the type of flour to be produced. © 2024 Society of Chemical Industry.

Development of a NiFe2O4 covalent organic framework based magnetic solid-phase extraction approach for specific capture of quinolones in animal innards prior to UHPLC-Q-Orbitrap HRMS detection.

This study aimed to present a selective and effective method for analyzing quinolones (QNs) in food matrix. Herein, a NiFe2O4-based magnetic sodium disulfonate covalent organic framework (NiFe2O4/COF) was prepared using a simple solvent-free grinding method, and was adopted as a selective adsorbent for magnetic solid phase extraction of QNs. Coupled with UHPLC-Q-Orbitrap HRMS, an efficient method for simultaneous detection of 18 kinds of QNs was established. The method exhibited good linearity (0.01-100 ng g-1), high sensitivity (LODs ranging from 0.0011 to 0.0652 ng g-1) and precision (RSDs below 9.5%). Successful extraction of QNs from liver and kidney samples was achieved with satisfactory recoveries ranging from 82.2% to 108.4%. The abundant sulfonate functional groups on NiFe2O4/COF facilitated strong affinity to QNs through electrostatic and hydrogen bonding interactions. The proposed method provides a new idea for the extraction of contaminants with target selectivity.

Clinical Study of a Four-Step Program for the Treatment of Plantar Fasciitis with Bone Spurs.

OBJECTIVE: The most common causes of plantar and heel pain are plantar fasciitis and calcaneal spurs, and they often co-exist. Surgery is a recognized treatment for refractory plantar fasciitis. However, few studies have proposed treatment options for patients with metatarsophalangeal fasciitis with bone spurs. Accordingly, this study's purpose was to propose a four-step surgical regimen, and to improve the surgical outcome of plantar fasciitis with osteophytes and to establish a procedure for surgical treatment. METHODS: Retrospective analysis of 45 patients suffering from plantar fasciitis with bone spurs from 2020 to 2023. All patients underwent a four-step procedure, including plantar fascia release, calcaneal spur grinding, inflammatory tissue removal, and calcaneal burr decompression. The imaging parameters and functional scores were recorded before and after the operation. The objective evaluation included the measurement of calcaneal spur length on radiographs. Clinical evaluation included the American Orthopaedic Foot and Ankle Society (AOFAS), the Visual Analog Scale (VAS), and the Foot and Ankle Outcome Scale (FAOS). Measurement data that conformed to normal distribution were expressed as (x2 ± s), and pre-and postoperative AOFAS, FAOS, and VAS scores were compared using repeated-measures ANOVA, and preoperative and postoperative spur lengths were compared using paired t-tests. RESULTS: The 45 patients were followed up for 3 to 30 months, (17.72 ± 8.53) months, at final follow-up, the patient's AOFAS score improved from preoperative (74.93 ± 5.56) to (94.78 ± 3.98), FAOS score increased from preoperative (76.42 ± 3.37) to (96.16 ± 2.74), the VAS score decreased from (3.18 ± 0.54) to (1.07 ± 1.20) (p < 0.05), the length of spur decreased from (0.72 ± 1.81) cm to (0.23 ± 1.19) cm, and there were significant differences before and after operation (p < 0.05). CONCLUSION: The four-step surgical regimen is an appropriate and effective surgical procedure to treat plantar fasciitis with bone spurs.

Fabrication and Application of Grinding Wheels with Soft and Hard Composite Structures for Silicon Carbide Substrate Precision Processing.

In silicon carbide processing, the surface and subsurface damage caused by fixed abrasive grinding significantly affects the allowance of the next polishing process. A novel grinding wheel with a soft and hard composite structure was fabricated for the ultra-precision processing of SiC substrates, and the grinding performance of the grinding wheel was assessed in this study. Different types of gels, heating temperatures, and composition ratios were used to fabricate the grinding wheel. The grinding performance of the grinding wheel was investigated based on the surface integrity and subsurface damage of SiC substrates. The results showed that the grinding wheel with a soft and hard composite structure was successfully fabricated using freeze-dried gel with a heating temperature of 110 °C, and the component ratio of resin to gel was 4:6. A smooth SiC substrate surface with almost no cracks was obtained after processing with the grinding wheel. The abrasive exposure height was controlled by manipulating the type and ratio of the gel. Furthermore, the cutting depth in nanoscale could be achieved by controlling the abrasive exposure height. Therefore, the fabrication and application of the grinding wheels with soft and hard composite structures is important for the ultra-precision processing of large-size SiC substrates.

Effects of Two Different Methods of Teeth Grinding on Dental Injuries, Skin Lesions, Growth and Behaviour of Suckling Piglets Compared to a Non-Treated Control Group.

Teeth grinding in suckling piglets is performed on many farms to protect the piglets' littermates and the sow's udder from injuries caused by the piglets' canines and third incisors. In this study, the effects of two teeth-grinding methods on the piglets' dental health and welfare were investigated. The piglets of a litter were evenly assigned to a treatment: one-third of littermates were ground with a roller grinding head (RG), one-third with a teacup grinding head (TCG), and one-third were not ground at all (CG). A random sample of 100 animals each from the RG and TCG treatment was examined for tooth injuries, i.e., dental pulp openings. Additionally, behavioural analysis was performed (n = 650 piglets), and skin lesions, growth and mortality were determined (n = 1565 piglets). TCG piglets had a lower risk (p < 0.001) of pulp opening than RG piglets (0.08 ± 0.31 vs. 2.67 ± 1.67 opened pulps per piglet). Mortality, growth, skin lesions and behaviour of piglets were not influenced by treatment (p > 0.05). This study showed that both teeth-grinding methods led to pulp openings. If teeth grinding cannot be avoided on a farm, using the teacup grinding head is recommended concerning animal health and welfare.

Investigation on the Deformation and Surface Quality of a Bearing Outer Ring during Grinding Processing.

Thin-walled bearings are widely used owing to the advantages of their light structure, high hardness, and strong load-carrying capacity. However, thin-walled bearings are often prone to deformation during the machining process, which can seriously affect the performance of the bearings. In addition, the machining deformation and quality of bearings are difficult to balance. To address the above issues, this paper investigates the effects of the machining parameters on the machining deformation, surface quality, and machining efficiency of a thin-walled bearing during the roughing stage. The dynamic balance between deformation inhibition and high quality in rough grinding was studied, and the optimal parameters for thin-walled bearing outer ring grinding were obtained. The deformation mechanism of thin-walled bearings caused by grinding was revealed through simulation and experimental analysis. The results show that the machining deformation and quality reach a balance when the workpiece speed is 55 r/min, the grinding wheel rotational speed is 2000 r/min, and the feed rate is 0.1 mm/min. Deformation increases with the increase in workpiece speed and grinding wheel speed. At the same time, the surface roughness increases with the increase in the workpiece speed, but the increase in the wheel speed will improve the surface roughness. As the workpiece speed increases, the surface topography shows a more pronounced stockpile of material, which is ameliorated by an increase in grinding wheel speed. As the rotational speed of the workpiece increases, the number of abrasive grains involved in the process per unit of time decreases, and the surface removal of the workpiece is less effective, while the increase in the rotational speed of the grinding wheel has the opposite effect. The grinding deformation of thin-walled bearings is mainly induced by machining heat and stress. As the rotational speed increases, the heat flux in the grinding zone increases. More heat flux flows into the surface of the workpiece, causing an increase in thermal stresses on the inner surface of the bearing collar, leading to greater deformation. The temperature in the grinding area can be reduced during machining, realizing a reduction in deformation. The research content contributes to the balance between high quality and low distortion in machining processes.

Effect of the Axial Profile of a Ceramic Grinding Wheel on Selected Roughness Parameters of Shaped Surfaces Obtained in the Grinding Process with a Dual-Tool Grinding Head.

The use of CNC equipment that integrates several machining operations eliminates downtime due to changes in setup and clamping of workpieces in more than one machining device. A review of CNC equipment and tools known from the literature and from manufacturers' offerings indicates that new technical solutions are being developed to integrate two or more technological operations. However, these examples have numerous limitations and are mostly not suitable for machining surfaces with complex shapes. An example of such solutions is the use of a dual-tool grinding head, which integrates the process of rough grinding with a ceramic grinding wheel and finish grinding with a flexible grinding wheel. Unfortunately, it has the disadvantage of being limited by the angular shape of the ceramic grinding wheel, making it unable to adapt to the complex geometries of the shaped surfaces being ground. The need to overcome this limitation became the motivation for the research work described in this article. By means of experimental research, it was verified what effect the radial outline on the periphery of a ceramic grinding wheel realized by rough grinding would have on the surface roughness parameters obtained in the process of grinding shaped surfaces. For this purpose, grinding processes using a ceramic wheel with a conical and radial outline were compared. The result of the study was a summary of the surface roughness parameters Sa, St, Sq, Spk, Str, and Sds obtained after two-stage machining (rough and finish grinding). The obtained analysis results showed that changing the axial outline of the ceramic grinding wheel makes it possible to significantly expand the range of applications of the dual-tool head without negatively affecting the quality of the machined surface. Thus, such an improvement will make it possible to increase the applicability of the head by grinding shaped surfaces with a radial profile of curvature.

Morphological Study before and after Thermal Treatment of Polymer-Polymer Mixed-Matrix Membranes for Gas Separations.

A good integration of the polymer materials that form a mixed-matrix membrane (MMM) for gas separation is essential to reaching interesting permselective properties. In this work, a porous polymer network (PPN), obtained by combining triptycene and trifluoroacetophenone, has been used as a filler, which was blended with two o-hydroxypolyamides (HPAs) that act as polymer matrices. These polymer matrices have been thermally treated to induce a thermal rearrangement (TR) of the HPAs to polybenzoxazoles (ß-TR-PBOs) through a solid-state reaction. For its structural study, various techniques have been proposed that allow us to undertake a morphological investigation into the integration of these materials. To access the internal structure of the MMMs, three different methods were used: a polishing process for the material surface, the partial dissolution of the polymer matrix, or argon plasma etching. The argon plasma technique has not only revealed its potential to visualize the internal structure of these materials; it has also been proven to allow for the transformation of their permselective properties. Force modulation and phase contrast in lift-mode techniques, along with the topographic images obtained via the tapping mode using a scanning probe microscope (SPM), have allowed us to study the distribution of the filler particles and the interaction of the polymer and the filler. The morphological information obtained via SPM, along with that of other more commonly used techniques (SEM, TGA, DSC, FTIR, WASX, gas adsorption, and permeability measurements), has allowed us to postulate the most probable structural configuration in this type of system.