Polymer Mass Ratio Research Articles

Study on the Polymer Morphology and Electro-Optical Performance of Acrylate/Epoxy Resin-Based Polymer-Stabilized Liquid Crystals Based on Stepwise Photopolymerization.

Stepwise photopolymerization is a miraculous strategy modulating the polymer skeleton and electro-optical properties of light modulators based on liquid crystal/polymer composites. However, owing to the indistinct polymerization mechanism and curing condition discrepancy, the required polymer structures and electro-optical properties are hard to be controlled precisely. Herein, a novel polymer-stabilized liquid crystal film based on acrylate/epoxy resin is proposed, fabricated and the relationships between preparation process, polymer content, polymer morphology and electro-optical properties are studied. The in-situ photopolymerization of acrylate/epoxy resin liquid crystalline polymer is fulfilled using cation photo-initiator UV 6976. The distinct photopolymerization speed between acrylate and epoxy resin benefits the polymer morphology control, and with accurate containment of the polymerization process and polymer composition, the superior electro-optical properties at a higher polymer content are acquired. The polymer morphology and electro-optical properties are influenced by the polymer content and mass ratio between acrylate and epoxy resin. The best electro-optical properties among samples are attained by controlling the mass ratio between acrylate and epoxy resin to 1:1, integrating higher densities of scattering centers and lower anchoring effect. With higher polymer content, the strategy of increasing the mass ratio of E6M benefits the improvement of E-O properties for alleviating polymer density. This work provides insights to stepwise polymerization of liquid crystalline monomers and offers a fancy strategy for the preparation of novel liquid crystal dimming films.

Ascorbic acid nanoencapsulation using polyelectrolyte complex formation and optimization using hybrid artificial neural network‐genetic algorithm

AbstractBackgroundsThe polyelectrolyte complex (PEC) formation using chitosan (Cs) and alginate (Alg) has been employed to carry out Vitamin C (VC) nanoencapsulation because of its instability in adverse conditions. This method includes VC nanoencapsulation using physical cross‐linking. The effect of the mixing order as well as the different mass ratios of both the polymer and the VC content, were investigated on the size, pdi, zeta potential, encapsulation efficiency (EE%), and yield%. Hence, considering different mass ratios of both polymer (4:1–1:4) and VC content (10%–30% w/w of Cs) as independent variables, PECs were formed using 0.1% (w/v) of Cs and Alg solution.ResultThe result showed that, for equal mass ratio (1:1) of Cs and Alg, the addition of Alg solution to Cs solution led to lower particle size, while higher particle size was observed with reverse order of addition. However, no significant effect of polymer mass ratios was observed on particle size and NPs stability, while EE varied with VC concentration. Artificial neural network (ANN) was applied to train the experimental parameters Cs: Alg ratios (X1:X2) and VC content (X3) for the output variables. Moreover, process optimization was carried out using multi‐objective genetic algorithm (MOGA) with the goal of lowering particle size and increasing EE while increasing nanoparticle yield.ConclusionThe PEC method effectively encapsulated VC as obtained from higher EE. The Cs: Alg ratio of 4:2.1 and 18% VC content (w/w of Cs) was found optimum for nanoencapsulation. The final ANN‐GA model showed an acceptable agreement with experimental data.

Preparation and Characterization of Spray-Dried Hybrid Nanocrystal-Amorphous Solid Dispersions (HyNASDs) for Supersaturation Enhancement of a Slowly Crystallizing Drug.

We prepared hybrid nanocrystal-amorphous solid dispersions (HyNASDs) to examine their supersaturation capability in the release of a poorly soluble drug, itraconazole (ITZ), a slow crystallizer during dissolution. The HyNASD formulations included a polymer (HPC: hydroxypropyl cellulose, Sol: Soluplus, or VA64: Kollidon-VA64) and a surfactant (SDS: sodium dodecyl sulfate). Additionally, the dissolution performance of the HyNASDs and ASDs was compared. To this end, wet-milled aqueous nanosuspensions containing a 1:5 ITZ:polymer mass ratio with/without SDS as well as solutions of the same ratio without SDS in dichloromethane were spray-dried. XRPD-DSC confirmed that ASDs were formed upon spray drying the solution-based feeds, whereas HyNASDs (~5-30% amorphous) were formed with the nanosuspension-based feeds. SDS aided to stabilize the ITZ nanosuspensions and increase the amorphous content in the spray-dried powders. During dissolution, up to 850% and 790% relative supersaturation values were attained by HyNASDs with and without SDS, respectively. Due to the stronger molecular interaction between ITZ-Sol than ITZ-HPC/VA64 and micellar solubilization by Sol, Sol-based HyNASDs outperformed HPC/VA64-based HyNASDs. While the ASD formulations generated greater supersaturation values (≤1670%) than HyNASDs (≤790%), this extent of supersaturation from a largely nanocrystalline formulation (HyNASD) has not been achieved before. Overall, HyNASDs could boost drug release from nanoparticle-based formulations and may render them competitive to ASDs.

Study on anti-infrared performance of organohalogen polymer smoke agent

Presented herein is an experimental study on the organohalogen polymer smoke agent. In smoke box experiment, the transmittance of smoke agent at 3-5 μm and 8-14 μm was used as the index, the effects of each factor on the anti-infrared performance of smoke agent were analyzed by orthogonal test method. The results showed that the main factors affecting the extinction properties of the organohalogen polymer smoke agent in the infrared band were zinc magnesium mass ratios of Zn-Mg alloy powders, Particle size of Zn-Mg alloy powders, and types of organohalogen polymer, and the secondary factor was the organohalogen polymer mass ratio. The transmittance of the best organohalogen polymer smoke agent composed of 30% Zn-10%Mg alloy powder (>325mesh), 50% CP-70, and 20% KClO4 to the 3-5μm and 8-14μm bands is 27.67% and 58.07%, respectively, and the corresponding TOP is 93.82 m2·kg1 and 39.69 m2·kg1. The combustion of the smoke agent composed of Zn-10%Mg alloy powder and Zn powder was compared in combustion experiment. The smoke agent composed of Zn-10%Mg alloy powder instead of Zn powder has a faster burning speed, larger burning flame area, and higher temperature.

Simultaneous and selective removal of diclofenac and ibuprofen from aqueous matrices by a hybrid TiO2-dual-template molecularly imprinted polymer

ABSTRACT Dual-template molecularly imprinted polymer based on TiO2 nanoparticles (NPS) (TiO2-MIP) was synthesised by surface molecularly imprinted method to achieve the simultaneous and selective removal of diclofenac and ibuprofen in aqueous media. The characterisation results of Fourier Transformed Infrared spectroscopy (FTIR), X-ray Diffractometry (XRD), Brunauer, Emmett and Teller (BET) and Field Emission Scanning Electron Microscopy (FE-SEM) revealed the successful imprinting process on the surface of titania. The effects of operating parameters including pH, initial concentration of target pollutants and dosage of nanocomposite were first investigated. Then, TiO2-MIP nanocomposites were prepared at different TiO2 NPS to imprinted polymer mass ratios, and the optimal value was determined. The best treatment performance was obtained at pH = 4, 10 mg/L of target pollutants, 1 g/L of the nanocomposite, and 1:4 mass ratio, in which the simultaneous and selective removal efficiency of diclofenac and ibuprofen was 86.6% and 75.0%, respectively. The adsorption capacity of synthesised TiO2-MIP nanocomposites for DCF and IBP was 5.22 and 4.38 mg/g, respectively. The pseudo-second-order model (R2 ≥ 0.99) and Langmuir isotherm model (R2 = 0.99) demonstrated the best fitting with experimental data. The adsorption capacity, photodegradation activity, selectivity and reusability of polymeric nanocomposite were also studied. The results revealed that the synthesised TiO2-MIP nanocomposite had higher adsorption capacity, enhanced photodegradation performance and better selectivity for target pollutants than non-imprinted TiO2 nanocomposite. The results further showed that the selection factor of TiO2-MIP for diclofenac and ibuprofen was 5.4 and 3.8 times of the competitive pollutant, respectively, indicating stronger and more specific interactions for the target molecules. The brilliant adsorption and photodegradation performance, simultaneous removal of contaminants, good stability and selectivity towards target pollutants in the presence of competitive compounds are the advantages of the as-prepared TiO2-MIP nanocomposite. Thus, a hybrid TiO2-molecularly imprinted polymer can play an influential role in the treatment of persistent environmental insults in complex aquatic environments.

Phenylboronic acid-modified polymaleic anhydride-F127 micelles for pH-activated targeting delivery of doxorubicin

Phenylboronic acid (PBA) is a tumor-targeting molecule which selectively recognizes sialic acid (SA) overexpressed in tumors. In the study, PBA, F127 and ethanolamine were conjugated with poly(maleic anhydride) by one-step reaction to form amphiphilic polymer for doxorubicin encapsulation. Two drug-carrying micelles with different mass ratio of polymer to drug were prepared by dialysis method to study effect of PBA on doxorubicin release, tumor-targeting and antitumor activity. The study results showed that doxorubicin release from the formulations was acid-sensitive and affected by the polymer dosage, and its acid-induced release behavior improved its insertion into DNA base pairs. Formulation with high polymer dosage showed better tumor targeting and antitumor activity, and activity of inhibiting HepG2 with higher content of SA-containing glycosphingolipids was higher than that of anti-B16. In vivo studies on the activity of B16-bearing mice showed that the doxorubicin-loaded micelles could inhibit the tumor growth and were safer than free doxorubicin. Thus, the PBA-modified nano-polymer micelles have potential biomedical applications due to their nanostructure and tumor-targeting ability.

Chemical recycling of polyethylene in oxygen-enriched supercritical CO2

Thermal oxidation of polyethylene was carried out in oxygen-enriched sc CO2 and in pure oxygen under a pressure of 215 and 14 bar, respectively. Oxygen to polymer weight ratio was varied. At lower oxygen content, the products were brown to dark brown pastes; at higher oxygen content, the products were dark yellow to dark-brown liquids. For the oligomeric fraction of the products, the data on molecular weights obtained by means of diffusion-ordered NMR and gel permeating chromatography was compared. Thermogravimetric analysis demonstrated that oxygen content strongly affects the yield of volatile products. The volatile products were further analyzed by means of 1H, 13C NMR, gas chromatography-mass spectrometry and potentiometric titration. All the results obtained suggest that sc CO2 influence is more pronounced at lower oxygen to polymer mass ratio, which may be useful for carrying out chemical recycling of polyethylene through thermal oxidation while minimizing the amount of oxygen required.

Design of mucoadhesive gellan gum and chitosan nanoparticles intended for colon-specific delivery of peptide drugs

Nanotechnology has been widely used in the development of polymer nanocarriers for the oral delivery of biomolecules. The use of nanostructured systems can improve drug delivery and help to overcome the disadvantages of the oral administration of peptides. Nanoparticles (NPs) based on gellan gum (GG) and chitosan (CS) blends were prepared through polyelectrolyte complexation. The influence of pH on the zeta potential (ZP) of polymers allowed the selection of pH 5.0 as the most suitable pH for the complexation of polyelectrolytes. The effects of the polymer mass ratio and addition order on the formation and physicochemical properties of the NPs were evaluated. All NPs showed high positive ZP (> + 30 mV), which ensures electrostatic stability. The order of addition of the polymers influenced the particle size. Nanoscale structures (575.30–974.60 nm) were formed when GG (0.5–3 mg) was dripped into the CS dispersion (0.75–4.5 mg); however, when CS was dripped in the GG dispersion, particle aggregation occurred (sizes >5000 nm). Polymyxin B (PMB) nanoencapsulation reduced the particle size, mainly at low GG mass (1.5 mg). The PMB–polymer interactions were detected by Fourier transform infrared spectroscopy. The X-ray diffraction data indicated the formation of more organized structures with a higher degree of crystallinity. Scanning electron microscopy revealed spherical and uniform NPs. The mucoadhesive capability of the NPs was also demonstrated. The NP2_1 and NP2_3 released the lowest amount of drug in HCl 0.1 N (pH 1.2) (<29%), and the drug release rate was controlled in a phosphate buffer 0.1 M (pH 6.8) (<60%). The important findings of this study suggest that nanocarriers with tailored properties may be utilized to overcome the challenges of oral administration of peptides, such as PMB, contributing to the advances in the search for alternatives to the oral administration of PMB.

An Advanced Material with Synergistic Viscoelasticity Enhancement of Hydrophobically Associated Water‐Soluble Polymer and Surfactant

In order to prepare materials with controllable properties, changeable microstructure, and high viscoelasticity solution with low polymer and surfactant concentration, a composite is constituted by adding surfactant (sodium dodecyl sulfate, SDS) to hydrophobically associated water-soluble polymer (abbreviated as PAAC) solution. The viscoelasticity, aggregate microstructure, and interaction mechanism of the composite are investigated by rheometery, Cryo-transmission electron microscopy (Cryo-TEM), and fluorescence spectrum. The results show that when the mass ratio of polymer to surfactant is 15:1, the viscosity of the composite reaches the maximum. The viscosity of the composite system increases hundredfold. The viscosity plateau under dynamic shear is generated. The composite has the properties of high viscoelasticity, strong shear thinning behavior, and good salt tolerance, and temperature resistance. The maximum viscosity of the composite is shown at the salinity of 20000mg L-1 . In addition, there is no phase separation in the composite with the increase of polymer and surfactant concentration, which indicates the good stability of the system. It is proposed a method to obtain a high viscoelasticity solution by adding surfactants without wormlike micelles to a hydrophobically associated water-soluble polymer solution.

Development of electrospun polymer scaffolds for the localized and controlled delivery of siponimod for the management of critical bone defects.

Sphingosine 1-phosphate (S1P) receptor modulators can influence bone regeneration owing to their positive impact on osteoblast differentiation and neovascularisation. While previous studies have utilised non-specific S1P and fingolimod, this study aims to design and characterise a controlled release vehicle to deliver the specific S1P1 & 5 receptor modulator siponimod and test its effectiveness in rat critical cranial defects. Electrospun scaffolds of poly lactide-co-glycolide (PLGA) were loaded with siponimod at drug:polymer mass ratios of 0.5:100 to 2:100. Where indicated, collagen was co-spun at a collagen:polymer mass ratio of 2:100. Thereafter, scaffolds underwent in vitro physicochemical characterisation and in vivo assessment using a rat cranial defect model. Drug-loaded scaffolds showed controlled release of siponimod, -cytocompatibility with endothelial and osteoblast cells in vitro, and furthermore, showed that released siponimod stimulated osteoblast differentiation and endothelial cell migration. The in vivo cranial defect repair study showed regeneration was occurring in the defect, although there was no significant difference in the extent of mineralisation between scaffold experimental groups. To our knowledge, this is the first study investigating siponimod in bone regeneration. In vitro studies confirm a positive impact on key cells involved in bone regeneration, however, the scaffolds did not result in significant repair of critical cranial defects.

Application of Artificial Neural Networks to Predict the Catalytic Pyrolysis of HDPE Using Non-Isothermal TGA Data.

This paper presents a comprehensive kinetic study of the catalytic pyrolysis of high-density polyethylene (HDPE) utilizing thermogravimetric analysis (TGA) data. Nine runs with different catalyst (HZSM-5) to polymer mass ratios (0.5, 0.77, and 1.0) were performed at different heating rates (5, 10, and 15 K/min) under nitrogen over the temperature range 303–973 K. Thermograms showed clearly that there was only one main reaction region for the catalytic cracking of HDPE. In addition, while thermogravimetric analysis (TGA) data were shifted towards higher temperatures as the heating rate increased, they were shifted towards lower temperatures and polymer started to degrade at lower temperatures when the catalyst was used. Furthermore, the activation energy of the catalytic pyrolysis of HDPE was obtained using three isoconversional (model-free) models and two non-isoconversional (model-fitting) models. Moreover, a set of 900 input-output experimental TGA data has been predicted by a highly efficient developed artificial neural network (ANN) model. Results showed a very good agreement between the ANN-predicted and experimental values (R2 > 0.999). Besides, A highly-efficient performance of the developed model has been reported for new input data as well.

Rheological analysis of the interplay between the molecular weight and concentration of hyaluronic acid in formulations of supramolecular HA/FmocFF hybrid hydrogels

In this report, we evaluated the interplay between molecular weight and mass ratio of polymer during development of viscoelastic properties in HA/FmocFF hybrid supramolecular hydrogels. Rheology was the main tool to assess this complex relationship and the kinetics of network formation during self-assembly were correlated with inherent material properties. Formation of long-rang elastic interactions, ductility and plastic flow were strongly dependent on both size and concentration of polymer, providing a convenient application window to tune the flow properties of the hybrid hydrogels according to the intended application.

THERMOCATALYTIC DEGRADATION OF POLYPROPYLENE IN PRESENCE OF ALUMINUM SILICATES

The process of thermocatalytic conversion of polypropylene into liquid hydrocarbons using amorphous aluminum silicates with aluminum content of 1.6-12.9 wt.% as catalysts was studied. The aluminum silicates were synthesized by sol-gel method using hydrolysis of tetraethoxysilane in a presence of aluminum salt at pH=9. All samples possessed acidic sites with pKa value of 3.46-5.00 and had a developed surface. Textural properties of the aluminum silicates were determined. Thermocatalytic conversion of polypropylene was carried out in a flow fixed-bed reactor with a fixed layer of the mixture of the catalyst and the reagent at a mass ratio of polymer : catalyst of 3 : 1 in argon atmosphere with a gradual rise of temperature in the range of 300 – 450 ºС. The sample of silica, which did not contain aluminum, was demonstrated to be inactive in polypropylene degradation, while other catalysts provided conversion of polypropylene into liquid products. The highest yield of liquid products was 80% for a catalyst with an aluminum content of 8.1 wt.%. According to the results of GLC saturated hydrocarbons were identified among the products for all samples. The effect of the concentration of acidic centers on the chemical and fractional composition of the target products was shown. For the studied aluminum silicates with the same pKa values, an increase in the aluminum content favored the formation of a lighter hydrocarbon fraction. For the catalyst with the highest aluminum content the n-alkanes of С5-С10 composition were identified. These products were closest to gasoline oil fraction. This provides a possibility to consider secondary polyolefins as an alternative source of motor fuels. An influence of catalyst composition on maximal temperature of polyethylene degradation was determined by differential thermal analysis.

Microfluidic-assisted polymer-protein assembly to fabricate homogeneous functionalnanoparticles.

Functional polymer-protein nanoparticles (NPs) have broad applications in biotechnology and nanotechnology. In principle, controllable and vigorous mixing is required to fabricate homogeneous NPs, which remains a challenge via conventional bulk synthetic methods. In this study, an electrokinetics (EK) based microfluidic reactor with fast mixing is explored to assemble functional proteins with polymers in an ethanol/water co-solvent system. The resultant NPs show significantly improved size distribution by comparison with the ones prepared using conventional bulk method, while the NPs size can be tuned by adjusting the mass ratio of polymer to protein. The functionalities of the assembled proteins are sustained upon the EK based microfluidic mixing, indicating the application potential of our method in the controlled assembly of different functional proteins.

Computation fluid dynamic simulation and experimental validation of shear induce dissociation coupling ultrafiltration technology for the treatment of lead contained wastewater

A novel technology, shear induced dissociation coupling with ultrafiltration (SID-UF), is used to for the treatment of lead contained wastewater for the first time. Two kinds of water soluble polymer, poly(acrylic acid) sodium (PAAS) and copolymer of maleic acid and acrylic acid (PMA), are used as complexants. The mass ratio of polymer to metal ions (P/M), pH and rotary speed are optimized by full recycle processes. The experimental results reveal that the critical shear rate of the PMA-Pb complex is less than that of the PAA-Pb complex at the same pH, that is to say, PMA-Pb complex is less stable than PAA-Pb complex in the shear field. The velocity field and shear field are simulated by CFD. Moreover, the quantum chemical computation and the frontier molecular orbitals also demonstrates that the PMA-Pb complex shows a lower energy gap than that of PAA-Pb complex. Furthermore, the reuse of complexant is achieved by shear enhance diafiltration. PMA is better for the treatment of lead contained wastewater by SID-UFdue to its higher load capacity of Pb (II) and easier regeneration.

Recovery of metals and complexant in wastewater by shear induced dissociation coupling with ultrafiltration

ABSTRACTHeavy metals (Pb (II), Hg (II), and Cd (II)) in ore dressing wastewater (ODW) were selectively separated by shear‐induced dissociation coupling with ultrafiltration (SID‐UF) using polyacrylic acid sodium (PAAS) as complexant. Metals (Pb (II), Hg (II), and Cd (II)) were complexed with PAAS and rejected by ultrafiltration membrane at first. The effects of pH and P/M (mass ratio of polymer to metal ions) on the rejection were investigated and the suitable pH and P/M were obtained, at which the rejection arrived at almost 100%. For the recovery of metals and polymer complexant from the retained, the shear stabilities of PAA‐metal (PAA‐M) complexes were studied, and the critical shear rates of PAA‐Pb, PAA‐Hg, and PAA‐Cd complexes at pH 7.0 were 2.72 × 10,5 2.42 × 105 and 2.01 × 105 s−1, respectively. According to the difference of the critical shear rates of the PAA‐M complexes, SID‐UF was used to recover Pb (II), Hg (II), Cd (II) and PAAS. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48854.

SELECTIVE SEPARATION OF Mn(II) AND Cd(II) AS WELL AS REGENERATION OF POLYMER VIA SHEAR INDUCED DISSOCIATION COUPLING WITH ULTRAFILTRATION

Abstract The selective separation of Mn(II) and Cd(II) as well as regeneration of the complexing agent were conducted by shear induced dissociation coupling with ultrafiltration (SID-UF), and the copolymer of maleic acid and acrylic acid (PMA) was used as complexing agent. At the optimal complexation conditions, pH 6 and P/M (mass ratio of polymer to metal ions) 9, both the rejections of Mn(II) and Cd(II) arrived at more than 99%. The shear stabilities of two PMA-metal complexes at different pHs were particularly investigated using rotating disk membrane and the results indicated that critical shear rates γ c of PMA-Mn complex were lower than that of PMA-Cd at the same pH. According to the difference of the shear stabilities between PMA-Mn and PMA-Cd complexes, the selective separation of Mn(II) and Cd(II) were achieved by SID-UF at 1450 rpm and 1600 rpm, and PMA was regenerated.

Roles of surfactant and polymer in drug release from spray-dried hybrid nanocrystal-amorphous solid dispersions (HyNASDs)

We prepared hybrid nanocrystal–amorphous solid dispersions (HyNASDs) to enhance the dissolution of a poorly soluble drug, griseofulvin (GF), and elucidated the roles of a surfactant, sodium dodecyl sulfate (SDS), and two polymers, HPC and Soluplus. Wet-milled suspensions containing 1:1 to 1:5 GF:polymer mass ratios, with and without SDS, were spray-dried. HyNASD formation was confirmed via DSC, XRPD, and Raman spectroscopy. In dissolution tests, due to its sub-ambient glass transition temperature, poor miscibility with GF, its inability to inhibit GF recrystallization, HPC provided HyNASDs with low supersaturation capability (≤50%) even at the highest loading (1:5) with/without SDS. Contrarily, owing to its stronger intermolecular interactions–miscibility with GF, and its kinetic solubilization–inhibition of GF recrystallization observed in desupersaturation tests, Soluplus, with SDS, in HyNASDs achieved remarkably high supersaturation (>250%). SDS provided enhanced wettability, allowing for fast supersaturation from Soluplus-based HyNASDs (~300% within 20 min), while higher Soluplus loading led to higher supersaturation.

Hybrid nanocrystal–amorphous solid dispersions (HyNASDs) as alternative to ASDs for enhanced release of BCS Class II drugs

A major shortcoming of drug nanocomposites as compared with amorphous solid dispersions (ASDs) is their limited supersaturation capability in dissolution media. Here, we prepared drug hybrid nanocrystal–amorphous solid dispersions (HyNASDs) and compare their performance to ASDs. A wet-milled griseofulvin (GF, BCS II drug) nanosuspension and a GF solution, both containing the same dissolved polymer–surfactant (SDS: sodium dodecyl sulfate) with 1:1 and 1:3 GF:polymer mass ratios, were spray-dried. Hydroxypropyl cellulose (HPC) and Soluplus (Sol) were used as matrix-forming polymers. XRPD, DSC, and Raman spectroscopy reveal that ASDs were formed upon spray-drying the solution-based feed, whereas nanocomposites and nanocomposites with >10% amorphous content, HyNASDs, were formed with the nanosuspension-based feed. Sol provided higher GF relative supersaturation, up to 180% and 360% for HyNASDs and ASDs, respectively, in the dissolution tests than HPC (up to 50% for both) owing to Sol’s stronger intermolecular interactions and miscibility with GF and its recrystallization inhibition. Besides the higher kinetic solubility of GF in Sol, presence of GF nanoparticles vs. micron-sized particles in the nanocomposites enabled fast supersaturation. This study demonstrates successful preparation of fast supersaturating (190% within 20 min) HyNASDs, which renders nanoparticle formulations competitive to ASDs in bioavailability enhancement of poorly soluble drugs.

Selective separation of copper and zinc and regeneration of polymer from electroplating effluent using shear induced dissociation coupling with ultrafiltration

Shear-induced dissociation coupling with ultrafiltration (SID-UF) was used to remove and separate copper and zinc from both simulative effluent and real electroplating effluent using polyacrylate sodium (PAAS) as complex-ant. The effects of pH and the mass ratio of polymer on metal ions (P/M) on the removal of copper and zinc were investigated in the ultrafiltration tests, and the optimum pH and P/M were 7.0 and 25, respectively. The shear rate distributions on the membrane surface at various rotating speeds were simulated by CFD software. The shear stabilities of the polymer-metal complexes studied at various pHs indicated that the complexes would dissociate when the shear rate exceeded the critical shear rates (γc), and the order of critical shear rate was PAA-Zn>PAA-Cu at the same pH. The contrast between these two complexes shear stabilities was used to separate copper and zinc and recovery complexant from electroplating effluent by SID-UF. The results show that copper and zinc can be separated at 1.06×105 s-1 1.58×105 s-1. Compared to conventional complexation-ultrafiltration, SID-UF is a green and efficient method for the separation of metals and the regeneration of complexant.