Resin Particle Size Research Articles

Towards optimized cation-exchange membranes for overlimiting current electrodialysis: Correlation between size of resin particles in membranes and mechanism of ion transport through them

Experimental heterogeneous membranes with different particle sizes of cation-exchange resin KU-2–8 (the diameter of resin particles varied from 20 to 71 μm) were manufactured under the production conditions of LLC “IE “Shchekinoazot”. It is established that at currents higher than the limiting current the main mechanisms of electrolyte ion transport are classical electrodiffusion and electroconvection. It is shown for the first time that at the same degree of membrane polarization i/ilim the fraction of electroconvection contribution increases, and the fraction of contribution of water splitting reaction products decreases with decreasing size of resin particles in membranes. The theoretical evaluation of the influence of the size of resin particles in the membrane on the internal parameters of electromembrane systems MK-40/0.01M NaCl solution has shown that the crucial role in the development of electroconvection is played not by the field effect, but by the peculiarities of electrical heterogeneity of the membrane surface.

Recycling of waste wind turbine blades for high‐performance polypropylene composites

AbstractGlass fiber‐reinforced epoxy resin composite materials are widely used in various fields because of their excellent properties, especially in the stringent performance requirements of wind turbine blades manufacture for wind power generation. However, the irreversible cross‐linking network of the epoxy resin makes it difficult to recycle. In recent years, the management of large amounts of decommissioned wind turbine blade waste has become spotlight. This study used self‐developed solid‐state shear milling technology to effectively remove the epoxy resin from the glass fiber surface while preserving its high aspect ratio, ensuring its mechanical reinforcement potential. Furthermore, this process also significantly reduced epoxy resin particle size. Subsequently, composites with filler contents up to 50 wt.% were formulated with polypropylene. In the optimized composition, the material exhibited a remarkable 37.1% increase in tensile strength, 147.3% increase in modulus, and 63.8% increase in flexural strength, 165.5% in modulus, respectively. In this research, we conducted a comprehensive exploration into the effects of modifier structure and powder content on different properties of composites, contributing to a deeper understanding of these key factors.

External donor modified Mg-Ti based Z-N catalyst system for synthesis of Ultrahigh molecular weight polyethylene

This study reported novel external donors Diethyl 2,2'-(dimethylsilanediyl) diacetate (DSD1), Diethyl 2,2'-(phenyl(methyl) silanediyl) diacetate (DSD2) and Diethyl 2,2'- (diisopropylsilanediyl) diacetate (DSD3) and triethyl borate (TEB) employed with magnesium dichloride supported Ti-based monoester (Mg-Ti-ME) and magnesium dichloride supported Ti-based diester (Mg-Ti-DE) catalyst for synthesis of Ultrahigh molecular weight polyethylene (UHMWPE). Furthermore, the catalyst was tested with different concentrations of chain-terminating agents to understand the effect on molecular weight. The results showed Mg-Ti catalysts using DSD1, DSD2, and DSD3 and TEB external donors had significantly increased molecular weight in the presence of external donors with decreases in catalyst activity, compared to donor-free catalyst systems. In addition, in the presence of chain terminating agent molecular weight decreases significantly with less effect on catalyst activity. The obtained polymer, thermal properties characterized through differential scanning calorimetry (DSC), morphology through a scanning electron microscope (SEM), particle size of resin through a particle size analyzer and molecular weight through viscosity-average molecular weights method.

Rapid Preparation at Atmospheric Pressure and Gel Phase Analysis of Thermoplastic Phenolic Aerogels with High Specific Strength and Low Shrinkage

This article presents a rapid preparation method of phenolic aerogels using thermoplastic phenolic resin as a raw material under atmospheric pressure, a low temperature and mass fraction of the resin varying from 10 to 30%. The results showed that the initial stage of the aging time of the aerogel with resin mass fraction of 10% (PF-10) was at least 34 h to ensure no neck shrinkage during drying, while that with 30% phenolic content (PF-30) was only 1h. The prepared aerogels had a minimum density of 0.129 g/cm3 and a minimum shrinkage of 0.391%. With the increase of mass fraction of resin, the thermal conductivity of the aerogels decreased first and then increased, and PF-20 had the lowest thermal conductivity, being 0.037 W/(m·K). The effects of resin content on the microstructure were reflected in the pore size of aerogels which decreased from 773 nm for PF-10 to 43.328 nm for PF-30 and the particle size of the phenolic resin which decreased from 194 to 28 nm. The specific surface area increased from 37.707 to 177.231 m2/g, and the number of micropores increased. In terms of mechanical properties, the aerogel with 10% resin mass fraction had a minimum compressive strength of 0.342 MPa and a compressive modulus of 12.811 MPa, showing good elasticity. When the resin content was 30%, the strength and modulus increased to 8.309 and 348.060 MPa respectively. Its specific strength and specific modulus were 16.553 and 693.346 N·m/g, respectively, and the rigidity was greatly increased.

Effect of airborne particle abrasion treatment of two types of 3D-printing resin materials for permanent restoration materials on flexural strength.

This study aimed to assess the effects of airborne-particle abrasion (APA) on the flexural strength of two types of 3D-printing resins for permanent restoration. Two types of 3D printing resins (urethane dimethacrylate oligomer; UDMA, ethoxylated bisphenol-A dimethacrylate; BEMA) constituting different components were printed. The specimen surfaces were subjected to APA using 50 and 110µm alumina particles under different pressures. The three-point flexural strength was measured for each surface treatment group, and a Weibull analysis was performed. Surface characteristics were analyzed via surface roughness measurements and scanning electron microscopy. Dynamic mechanical analysis and nano-indentation measurements were limited to the control group. The three-point flexural strength according to the surface treatment was significantly lower in the UDMA group for large particle sizes and at high pressures; the BEMA group demonstrated low flexural strength for large particle sizes regardless of the pressure. After thermocycling, the flexural strengths of UDMA and BEMA significantly decreased in the group subjected to surface treatment. The Weibull modulus and characteristic strength of UDMA were higher than those of BEMA under different APA and thermocycling conditions. As the abrasion pressure and particle size increased, a porous surface formed, and the surface roughness increased. Compared with BEMA, UDMA featured a lower strain, greater strain recovery, and a negligible increase in modulus according to strain. Thus, surface roughness increased with the sandblasting particle size and pressure of the 3D-printing resin. Hence, a suitable surface treatment method to improve adhesion can be determined by considering physical property changes.

Preparation of tank-like resin-derived porous carbon sphere for supercapacitor: The influence of KOH activator and activation temperature on structure and performance

The resorcinol-melamine-formaldehyde (RMF) resin as a promising carbon precursor has aroused wide public concern due to its low cost, high nitrogen content, and ease of industrial production. In this work, the tank-like resorcinol–melamine-formaldehyde (RMF) resin spheres are synthesized via the hydrothermal method with the F127 assisting, and tank-like porous carbon spheres (TPCSs) are further prepared by pre‑carbonization and KOH treatment. The F127 is crucial in the formation of tank-like resin spheres and the influence of KOH dosage and activation temperature on morphology, particle size and structure-activity relationships for resin-based carbon spheres are explored in detail. The particle size of RMF resin and TPCSs-X-Y mainly locate at 1.75–2.75 μm and 1–1.8 μm, respectively. TPCSs-2-600 possesses a specific surface area of 1338 m2 g−1 and a high N content of 11.49 %. The specific surface area of resin-based carbon materials initially increases and then decreases with increasing KOH activator, which affects the specific capacitance in a similar trend. The rate performance of resin-based porous carbon materials gets better with increasing KOH dosage due to enhanced ion transport ability resulting from pore size getting larger. Increasing activation temperature enhances the specific surface area and pore size of the carbon electrode, but the specific capacitance reduces gradually in three-electrode system. The cycle stability of TPCSs-2-600 can be 87.8 % after 10,000 times charge-discharge cycles at 10 A g−1 in two-electrode system, and the symmetric supercapacitor assembled with TPCSs-2-700 electrode shows a good energy density of 6.68 Wh kg−1 with a power density of 484 W kg−1 in 6 M KOH aqueous electrolyte.

Using commercial resin for ion exchange to remove hardness from domestic water supply

The commercially available resins, Amberlite (A) and NuoSep (B), were used as ion exchange softeners for domestic water supply. The image, particle size, swelling, and bulk density of both resins were studied. The functional group of resins was investigated by Fourier transform infrared (FTIR) spectroscopy. Batch and continuous experiments were carried out at time 0–180 min and flow rate 10–40 cm3/min, respectively. An increase in contact time increased the percentage of the resins’ ion exchange. In contrast, a higher water supply flow rate decreased the percentage of the resins’ ion exchange. The efficiencies of both resins were slightly reduced after three cycles of regeneration. The equation from the Yoon–Nelson model could also be used to predict the breakthrough curve of ion exchange.

Kinetics of polyvinyl butyral (PVB) synthesis reaction catalyzed by deep eutectic solvent

AbstractIn this work, the kinetics of the polyvinyl butyral (PVB) synthesis reaction catalyzed by the deep eutectic solvents (DESs) at the low‐temperature stage was studied to control the particle size of PVB resin and optimize its synthesis process. The effects of stirring speed, the concentration of polyvinyl alcohol (PVA), catalyst dosage, and temperature on the synthesis reaction of PVB were investigated. The data obtained from kinetic experiments at 283.15–298.15 K were fitted with the shrinking core models, and the results showed that the model controlled by internal diffusion fitted well with the experimental data. The internal diffusion coefficient, DA, of n‐butanal in the product layer was further calculated by the obtained model parameters, and it was applied to predict the synthesis reaction of PVB at different concentrations of n‐butanal. The results indicated that the shrinking core model controlled by internal diffusion is suitable to describe the kinetics of the PVB synthesis reaction. DES played a dual role in catalysis and dispersion in the synthesis of PVB, and it was a green catalyst with good potential for PVB industrial applications.

Preparation of silicon carbide ceramic slurry for stereolithography based additive manufacturing

Stereolithography-based additive manufacturing of ceramics has received tremendous attention in academic and industrial communities. In order to fabricate silicon carbide (SiC) components with complex shapes by stereolithography, a high SiC loaded ceramic slurry with low viscosity and excellent curing ability is required. However, it is challenging to meet these slurry requirements. In this work, the effects of resin formulation, dispersant, particle size, solid content and ball milling time on the properties of SiC ceramic slurry were systematically studied. The SiC slurries were prepared by using four precursor SiC powders having different particle sizes and modified by high temperature oxidation to reduce its UV absorbance. Additionally, the suitable SiC slurries for stereolithography were prepared by ball milling under appropriate processing parameters, and the geometrically complex SiC green bodies were subsequently fabricated.

Effects of particle size on the adsorption behavior and antifouling performance of magnetic resins.

Adequately choosing the physicochemical characteristics of adsorbent is crucial in improving its adsorption performance. This work investigated the effect of particle size of magnetic resins on adsorption behaviors of tetracycline (TC) and their antifouling performance. Smaller particle size resin Q150 (10-30 μm) shows notably faster TC adsorption kinetics when compared resins with hundreds of microns (Q100 and Q1). Simulated by Weber-Morris equation, the film diffusion time of Q150 was only 20 min, 2-25 times faster than that of other resins. At this adsorption time, Q150 can reach more than 80% of the maximum adsorption, and the ring-like fluorescence images indicate that the molecules are accumulated on the external surface. Q150 also shows better reusability and antifouling performance over Q100 and Q1. After 20 adsorption-desorption cycles, the adsorption capacity of Q150 at 20 min only decreases 9.7%. The presence of tannic acid also only slightly decreases the adsorption capacity. The faster adsorption kinetics and the superior antifouling performance of Q150 make it a promising adsorbent in future use.

Preparation and Evaluation of Controlled Release of Eperisone Hydrochloride Resinate Beads by Complexing with Ion Exchange Resin

Complexes of ion-exchange resins and Eperisone hydrochloride, a model drug, were prepared using a batch method with different functional groups, loading equilibrium time, degree of cross linking, and resin particle size. Drug loading efficiency, mircromeritics properties and study of effect of cross linking and particle size on release behaviours, were also investigated. Most of the functional groups of resins were loaded with EpeH after the completion of a single batch method and it was recommended for drug loading into the ion-exchange resin. Using a batch method, drug loading could be monitored by simply measuring changes in the pH of the reaction medium since as complex formation reached completion, the pH returned to the initial pH of the eluent due to the limited amount of functional groups available for the exchange. EpeH could be loaded up to the ratio of 1 (drug): 1 (resin), depending on the physicochemical properties of the resin. As the cross linking ratio and particle size increased, release rate decreased due to the reduced effective diffusion coefficient and surface area.

Influences of the constraints of a separation task on the optimal selection of a cation exchanger resin

One important step in designing preparative chromatographic separation units is the selection of a well-performing adsorbent. Such selection is often based on selectivity factors which are calculated based on experimentally determined adsorption isotherms. Influences of constraints of the separation tasks, like purity demand, on the optimal selection are usually not considered. In this contribution, influences of the constraints of a separation task on the optimal adsorbent were investigated. First, a previously published model-based optimisation of the adsorbent selection using correlations between structural adsorbent properties with model parameters were extended by influences of particle size and ionic form of resins (Leipnitz et al., 1610). Model parameters of glucose and xylose for cation exchanger resins in Na+- and Ca2+-form with varying degrees of cross-linking and particle sizes were experimentally determined in a sequential parameter determination approach (Altenhoner et al., 1997). Correlations between the structural properties of resins and the model parameters were derived and applied in optimisation case studies. Following this approach, optimal structural properties were identified, increasing the volume-specific productivity of a separation of glucose and xylose, significantly. Further, the purity demand and feed composition were varied in different case studies, revealing the influences of constraints of a separation task on structural properties of optimal resins.

Preparation of autoxidative water-reducible alkyd resins from waste polyethylene terephthalate.

In this paper, the waste polyethylene terephthalate (PET) was glycolysed by trimethylolpropane with zinc acetate as catalyst. The effects of different content glycolysis product of waste PET on the appearance, viscosity, particle size and molecular weight of autoxidative water-reducible alkyd resins and the corresponding film adhesion, flexibility, impact resistance, gloss, hardness and chemical resistance were studied. Meanwhile, experimental results were compared with commercial water-reducible alkyd and water-reducible alkyd without the glycolysis product of waste PET. The results show that the maximum concentration of PET in autoxidative water-reducible alkyd resins can reach 8.5 wt%, and the molecular weight, particle size and viscosity of water-reducible alkyd resin do not change much with the increase of PET concentration. The introduction of PET resulted in the viscosity of water-reducible alkyd resins being greater than that of water-reducible alkyd resin without PET; this is mainly because PET contains harder terephthalic acid monomer units. However, the particle size of water-reducible alkyd resins with waste PET is significantly lower than that of the water-reducible alkyd resin without PET; this is due to PET-free water-reducible alkyd resin containing more pentaerythritol with greater steric hindrance. In addition, the hardness of the water-reducible alkyd resin paint film (PET content is 8.5%) reaches 1H, which is higher than the hardness (HB) of the water-reducible alkyd resin paint film without PET and the commercial alkyd resin paint film, while the physical properties and chemical resistance of the former are comparable to those of the latter two kinds of paint films. Therefore, the use of waste PET in water-borne coatings systems not only reduces the cost of coatings, but also opens up a new market for recycled PET, which may contribute a promising method for management of waste PET.

Kinetics of Tungstate and Phytate Adsorption by D201 Resin

Leaching of scheelite ore with phytate is a novel and clean hydrometallurgical method of isolating tungsten, which achieves efficient decomposition under atmospheric pressure. However, realizing the separation and recycling of tungstate and phytate has become an additional and subsequent problem, which had not been encountered in the traditional tungsten metallurgical process. In determining ways to overcome this obstacle, ion exchange methods exhibit promising routes to separate tungstate and phytate. Before performing this new method, it is prudent to study the kinetics of the ion exchange process. The effects of WO3 concentration, phytate concentration, resin particle size, and reaction temperature were investigated. Results show that a pseudo-second-order model can describe the adsorption kinetic behavior of phytate and tungstate in the mixed solution. The apparent activation energies of WO3 and phytate, based on the Arrhenius expression, were calculated as 21.4 kJ/mol and 21.8 kJ/mol, indicating that the adsorption processes of phytate and tungstate are diffusion-controlled.

Optimization of preparation conditions of composite electrodes for selective adsorption of vanadium in CDI by response surface methodology

In this work, a novel composite electrodes D314/activated carbon (AC) were prepared by D314 ion-exchange resin and activated carbon (AC) for the preferential adsorption of vanadium ion in capacitive deionization (CDI) technique. The conditions for preparing D314/AC composite electrode had been optimized using Response surface methodology (RSM). The vanadium (V) preferential adsorption characteristics, as affected by the weight ratio of resin to AC, the content of binder and the particle size of resin, were acquired by the Box-Behnken experimental design. In the optimized conditions, the average values of the adsorption amount of V, separation efficiency of V to iron (Fe) and aluminium (Al) reach 106.89±3.03mg/g, 2.08±0.08, 10.55±0.45, which were among the 95% confidence intervals (92.86, 110.10), (1.79, 2.16), (7.91, 12.24) of the predicted optimal value. The particle size of resin has the largest impact on the three response values, which will affect the specific surface area and specific capacitance of the composite electrode.

Effect of ion exchange resin particle size on homogeneity and leachability of Cs and Co in polymer waste form.

We report the size effect of ion exchange resins (IERs) on Cs and Co distribution in polymer waste forms. Ball mill ground IERs (BG) waste form resulted in relatively better homogeneous waste distribution and displayed superior Cs and Co leachability indexes compared with the same polymer waste form prepared with non-ground IERs (NG).

Seepage Characteristics of Emulsion with Phase Transition Behaviors

AbstractPetroleum resins have excellent thermal tolerance and selective plugging capability. As the environment temperature exceeds their softening point, petroleum resins transform from a solid into a viscous Newton fluid, accompanied by the transformation of the system from particle dispersoid to emulsion. The presence of phase transition decides that the seepage regularity and plugging characteristics of petroleum resins are different from either particle dispersoid or emulsion. Herein, rheological measurements and physical model flooding experiments were performed to investigate the injection and plugging performance of petroleum resins. A correlation chart of the injection pressure, formation permeability, and the ratio of resin particle size to pore diameter is established. The dispersoid is demonstrated to present good injectivity when the ratio of the resin particle size to the pore‐throat diameter of the porous media is lower than 0.35. Moreover, when the environment temperature is lower than or around the petroleum resin softening point, the injection performance of the dispersoid is not affected by temperature. Comparably, while the environment temperature is 30 °C higher than the resin softening point, the injection pressure increases due to phase transition. As indicated by the plugging experiment, the presented petroleum resin dispersoid plugging agent manifests excellent performance even in the case that the permeability of water‐channeling paths is up to 20 μm2, reaching a water plugging efficiency of over 85%. For water‐channeling fractures with widths of 0.05–0.5 mm, the plugging pressure gradient can exceed 5 MPa m−1. As suggested by combined analysis of injection and plugging performance, the disperse system should be optimized in accordance with the formation condition during field practice. Specifically, the ratio of the resin particle size to the formation pore diameter should be kept lower than 0.35, while the softening point of the petroleum resin should be 10–20 °C lower than the formation temperature.

Design of circular-ring film embedded contact lens for improved compatibility and sustained ocular drug delivery

Contact lenses are ideal medical devices to sustain the release of ophthalmic drugs. However, the incorporation of drug loaded system can cause visual obstruction and poor oxygen/light permeability which restrict the application of contact lens for long-term wearing. Inspired by the physiological structure of our human eyes, we assume a circular-ring type inner layer embedded CLs might be a good solution to address the above-mentioned problems. In this study, taking betaxolol hydrochloride (BH) as a model drug, its complex with ion exchange resin was used as a carrier for adjusting drug loading amount, which is being dispersed into circular-ring shape Eudragit® S100 film as an inner layer, silicone-based hydrogel as the outer layer. Influence of resin particle size and drug/S100 ratio on drug release profiles was investigated. It was demonstrated that using resin as a carrier can not only increase drug loading amount but also sustain drug release, with the drug release rate well-tuned by either changing particle size of the resin or S100 ratio. Meanwhile S100 can well function as a pH-triggered drug release matrix, with limited drug leakage in the storage medium. Light transmittance of over 97% was achieved in the novel circular-ring layer-embedded CLs. Oxygen permeability coefficient (Dk) of the circular-ring film embedded CLs was 31.1 ± 3.7 barrer, similar to that of pure CLs. The sustained drug release behavior of this circular-ring embedded CLs was also well demonstrated in vivo. A level A IVIVC between in vitro drug release and in vivo drug concentration in tear fluid of the circular-ring embedded CLs was established. In conclusion, this circular-ring embedded contact lens is very promising for ophthalmic drug delivery with enhanced compatibility, sustained and pH triggered drug release characteristics.

Influence of resin content on the surface covered with adhesive

It is well known that the resin content within a particleboard influences the extent of the surface covered with adhesive and thus the properties of particleboards produced. The purpose of this research was to determine how the resin content and particle size class influence the surface of particle covered with the adhesive. For that purpose, wood particles used for particleboard production were used. Particles were blended with a UF adhesive with 0.05% of fluorescent dye added prior to blending and subsequently exposed to a resin curing temperature of 180 °C. The resin content was varied between 7.5 and 12.5%. The adhesive surface coverage was determined using a microscope with a fluorescent light source and a CCD camera. The results showed that the surface coverage increased with increasing resin content and increasing wood particle size.

The mechanism of solifenacin release from a pH-responsive ion-complex oral suspension in the fasted upper gastrointestinal lumen

The main objective of this study was to investigate the mechanism of solifenacin release from a pH-responsive ion-complex oral resinate suspension under conditions simulating the environment in the upper gastrointestinal lumen. A secondary objective was to propose an appropriate in vitro methodology for evaluating the quality of orally administered solifenacin suspensions. The mechanism of solifenacin release from polacrilin potassium resin (Amberlite® IRP88) was investigated using biorelevant media and compendial setups (USP Apparatus 2 and USP Apparatus 4) and using newer, recently validated in vitro methodologies [biorelevant gastrointestinal transfer (BioGIT) system]. We evaluated the impact of particle size and concentration of the resin; thickener concentration (carbomer homopolymer, type B); and the impact of pH, cationic strength, agitation intensity and level of simulation of contents in the upper gastrointestinal lumen. Data suggested that solifenacin release from the resinate was determined by the resin particle size, the medium pH, cationic strength (when the conditions in the upper small intestine are simulated) and the level of simulation of contents in the upper small intestine. The interaction of solifenacin with taurocholic acid/lecithin aggregates was significant, but unlikely to affect the degree of solifenacin absorption, as a BCS Class I compound. Under acidic conditions, solifenacin was dissociated and released from the pH-responsive resin rapidly. Under conditions simulating the contents of the upper small intestine, solifenacin was replaced by cations from the testing media and diffused through the resin matrix. All three in vitro systems with or without a pH gradient are useful in distinguishing solifenacin release characteristics from resinate suspensions with different particle sizes. Because of this drug release mechanism, USP Apparatus 2 with fixed pH media demonstrated equivalent or slightly higher discriminative sensitivity than the other setups and appears to be appropriate for product quality control.