Preparation,characterization and drug release behavior of poly(acrylic acid–co-2-hydroxyethyl methacrylate-co-2-acrylamido-2-methyl-1-propanesulfonic acid) microgels

In this paper, Poly(acrylic acid-co-2-hydroxyethyl methacrylate-co-2-acrylamido-2–methyl-1–propanesulfonic acid (AAc-HEMA-AMPS) microgels were synthesized by using an inverse suspension polymerization technique. The increase in the AMPS content of the microgels composition caused a large increase in water uptake. The morphology of the microgels was examined by environmental scanning electron microscopy (ESEM). The AMPS containing microgels had a mean particle diameter of 10 μm. The glass transition temperature of the microgels were examined by DSC and found that they show single Tg. Lidocaine (LD) and Methylene blue (MB) were used as model drugs for the investigation of drug release behavior of the microgels. Different drug release patterns were observed, for LD and MB loaded microgels. The release studies showed that some of the basic parameters affecting the drug release behavior of microgels were the specific and non-specific interactions between microgel and drug structure and pH of the dissolution medium. These hydrogels may be potential candidates for pH-sensitive applications.     

Preparation and characterization of the poly(2-hydroxyethyl methacrylate)–salicylic acid conjugate

A new polymeric system containing hydrolysable ester bond linked to salicylic acid to be used for controlled drug release was synthesized. Poly(2-hydroxyethyl methacrylate) (PHEMA) functionalized with chloroacetate groups was obtained by the reaction between PHEMA and chloroacetyl chloride using the N,N-dimethylacetamide/5% lithium chloride system as a solvent and pyridine as a catalyst. The degree of substitution was calculated from the chlorine content and ranged from 32.2 to 98.1 mol.% depending on the ratio of chloroacetyl chloride to PHEMA. The coupling of salicylic acid to PHEMA functionalized with chloroacetate groups was carried out by the reaction between PHEMA and the sodium salt of salicylic acid. The structures of chloroacetylated PHEMA and PHEMA–salicylic acid conjugates were determined by means of FTIR, ¹H-NMR and ¹³C-NMR spectra. The hydrolysis in the heterogeneous system of PHEMA–salicylic acid conjugates were performed in buffer solutions (pH 7.6 and 8.5) at 37 °C and showed that the release of the drug (sodium salicylate) from tablets was dependent on the hydrophilic character of conjugate as well as on the pH value of the medium.     

Characterization of slow-release collagen-g-poly(acrylic acid-co-2-acrylamido-2-methyl-1-propane sulfonic acid)–iron(III) superabsorbent polymer containing fertilizer

A novel, slow-release polymer containing phosphorous fertilizer was synthesized by the rapid coordination of iron ions with polymers after the microwave radiation polymerization of collagen, 2-acrylamido-2-methyl-1-propanesulfonic acid, and acrylic acid. We obtained an optimized collagen-g-poly(acrylic acid-co-2-acrylamido-2-methyl-1-propane sulfonic acid) collagen-g-p(AA-co-AMPS)–Fe(III) polymer with great equilibrium swelling capacities of 2595 g/g in distilled water and 121 g/g in 0.9 wt % NaCl solution and an excellent sustained fertilizer release of about 30 days. In addition, for the collagen-g-p(AA-co-AMPS)–Fe(III) polymer, the effect of cations on its swelling followed the order K⁺ > Na⁺ > Mg²⁺ > Ca²⁺. The structure and morphology were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Moreover, the collagen-g-p(AA-co-AMPS)–Fe(III) polymers emancipated the nutrients in a more controlled manner than collagen-g-p(AA-co-AMPS). The thermal stability, water absorbency, and good slow-release of fertilizer provide the collagen-g-p(AA-co-AMPS)–Fe(III) polymer with great potential as a fertilizer-carrying vehicle and an aquasorb to be applied in agriculture and horticulture. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47178.     

Untreated Silica Nanoparticles Containing Poly(acrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid) Composite—Effect of Copolymer Composition

Poly(acrylamide-co-2-acrylamido-2-methyl-1-propanesulfonic acid)/Silica [Poly(AM-co-AMPSA)/SiO₂] core-shell composite nanogels with silica as core and hydrophilic polymer with functional groups such as sulfonic acid, amido, as shell were prepared by microemulsion polymerization without surface treatment of silica and upto 5.5 mole% of AMPSA in feed to control the particle size as well as morphology. The synthesized intercalated composites were produced with controllable sizes ranging from 44–77 nm in diameter. The repared sulfonic acid based silica core-shell composite nanogels were characterized by dynamic light scattering, transmission electron microscope, Fourier transform infrared spectrophotometer, thermogravimetric analyzer, differential scanning calorimeter, scanning electron microscope and X-ray diffraction. The encapsulation of functional polymer shell onto the silica particles was driven by the hydrogen-bonding interaction between sulfonic acid and amido groups of AMPSA with Si-O linkages. The onset degradation temperature is increased from 227°C to 262°C in copolymer-silica composites which indicates improved thermal stability. The shifting of glass transition temperature from 194°C to 203°C in copolymeric composite nanogels further confirms the existence of strong interactions of silica filler with copolymer chains. Also the chemical composition of polymeric chains and the affinity of polymer chains and silica influenced the morphology.     

Synthesis, characterization, and sorption properties of water-insoluble poly(2-acrylamido-2-methyl-1-propane sulfonic acid)–montmorillonite composite

The sorption properties of composites based on 2-acrylamido-2-methyl-1-propane sulfonic acid and montmorillonite are presented. Gel-type composites were obtained via in situ polymerization. Resin particles presented exfoliated morphologies, as suggested by X-ray diffraction. The addition of montmorillonite resulted in enhanced mechanical properties, as evaluated by Vickers microhardness tests. The swelling performances of the resins exhibited a fast initial water uptake, reaching the maximum absorption capacity after less of 1 h of contact. A batch procedure was used to evaluate the sorption characteristics of the composites, and the effects of pH, montmorillonite content, and time were studied. The composites showed high adsorption capacities at pH values of 3.0 and 5.0, and the addition of montmorillonite did not result in a significant enhancement of their adsorption capacity. The equilibrium adsorption performance can be described by the Langmuir isotherm, while kinetic experiments revealed an excellent agreement with the pseudo-second-order model.     

Synthesis of Multiwalled Carbon Nanotubes–Poly(Methacrylic Acid) Nanohybrid Systems: Characterization,Thermal Properties,and In Vitro Release Studies of Naproxen as a Model Drug

Nanohybrid systems based on carbon nanotubes and pH-sensitive poly(methacrylic acid) were prepared through attaching polymer chains onto carbon nanotubes. First, polymerizable groups were attached onto carbon nanotube walls, then the polymerizable groups were copolymerized with different ratios of methacrylic acid. Obtained systems were studied and characterized through Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy. A model drug (naproxen) was entrapped into the prepared materials and in vitro release studies were performed in pH 1 (simulated gastric fluids) and pH 7.4 (simulated intestinal fluids). It was noticed that release in simulated intestinal fluids was faster than simulated gastric fluids, therefore the prepared nanohybrid systems can be considered as appropriate carriers for colon-specific drug delivery.     

Preparation,characterization, and drug release properties of poly(2-hydroxyethyl methacrylate) hydrogels having β-cyclodextrin functionality

A new β-cyclodextrin urethane-methacrylate monomer was synthesized from the reaction of toluene-2,4-diisocyanate, 2-hydroxyethyl methacrylate (HEMA), and β-cyclodextrin (β-CD). Based on inclusion character of β-CD, a series of hydrogels were prepared by irradiating the mixtures of β-cyclodextrin urethane-methacrylate monomer (β-CD-UM), poly(ethylene glycol) diacrylate (PEG-DA), HEMA, and the photoinitator. Gel percentages and equilibrium swelling ratios (%) of hydrogels were investigated. It was observed that the equilibrium-swelling ratio increased with increasing β-CD-UM content in the hydrogel composition. SEM images demonstrated that β-CD-UM based hydrogel have porous fractured surface. In this study four different drug molecules, salicylic acid, sulfathiazole, rifampicin, and methyl orange as model drug, which are capable of forming inclusion complexes withβ-CD were chosen. For sulfathiazole and rifampicin, the drug loadings are very low (0.04 and 0.008 mmol/g dry gel), whereas methyl orange and salicylic acid drug uptakes are found as 0.15 and 0.18 mmol/g dry gel, respectively. The incorporation of β-CD-UM comonomer into the gel slightly reduces the methyl orange and salicylic acid releases. However, a significant enhancement was achieved in the case of sulfathiazole delivery. It can be concluded that the inclusion complex formation capability of β-CD moiety increases the drug release by improving the aqueous solubility of hydrophobic drugs. On the other hand, in the case of hydrophilic drugs, the drug release retards by forming strong drug-β-CD complex and reducing the drug diffusivity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Interfacial Interaction Analysis of Blends of Poly(vinylidene fluoride) and Poly(ethylene–butylacrylate–glycidyl methacrylate) Compatibilized by Poly(butylene succinate): Morphologies,Rheological Behavior,and Mechanical Properties

Poly(vinylidene fluoride) (PVDF) and poly(ethylene–butylacrylate–glycidyl methacrylate) (PTW) are polymers with weak interfacial adhesion. Blends based on PVDF and PTW (50/50?w/w) with poly(butylene succinate) (PBS) (0, 1, 3, 5, 7?wt%) are obtained by compression molding. The estimation of interfacial interaction among PVDF, PTW, and PBS and the properties of PVDF/PTW blends are investigated. The optimal content of PBS to form a co-continuous morphology in PVDF/PTW blends is proposed, indicating that the beneficial effect of PBS (7?wt%) on interfacial adhesion is observed. Overall, estimating interfacial adhesion is a critical issue for designing PVDF/PTW blend with excellent performance, which has a prospect in coating.     

Synthesis,Curing Behavior and Characterization of Epoxyacrylate and Triethylamine Cured Epoxy Resin of 1,1′-Bis(3-methyl-4-hydroxy phenyl) cyclohexane

Epoxy resin of 1,1′-bis(3-methyl-4-hydroxy phenyl) cyclohexane (EMC) and its acrylate (EMCA) have been synthesized and characterized. EMC has been cured by 5–25% triethyl amine at 100°C. The cured samples are characterized by solubility, IR, DSC and TGA at 10°C/min heating rate in nitrogen atmosphere. The associated kinetic parameters for EMCA, EMCT-5 and EMCT-20 have been determined according to Freeman-Anderson method and discussed. It is observed that EMCA and EMCT-20 have almost same thermal stability (300–308°C) but for EMCT-5 it is slightly lower (285°C). Cured samples followed fractional order degradation (0.63–1.44). In case of EMCT-5, all determined kinetic parameters are marginally lower than those of EMCA and EMCT-20.     

Preparation in supercritical CO2 of porous poly(methyl methacrylate)–poly(l-lactic acid) (PMMA–PLA) scaffolds incorporating ibuprofen

Partially biodegradable porous scaffolds incorporating bioactive molecules prepared by clean techniques posses an enormous interest in tissue engineering applications. Poly(methyl methacrylate)–poly(l-lactic acid) (PMMA–PLA) blends were submitted to CO₂ supercritical conditions (P = 160–260 bar, T = 60 °C) after certain time and then rapidly depressurized to obtain porous structures that have been related with the supercritical parameters and to the polymer blend composition. In some cases ibuprofen was also incorporated to the formulations previously to the CO₂ treatment and studied the appropriate conditions for avoiding its extraction in SCCO₂. Scaffolds purity, thermal transitions, swelling and degradation behaviour, and the ibuprofen release were also studied to determine the appropriate scaffolds with a desired porosity for cell seeding. Cell culture was performed on the selected porous scaffolds using human fibroblast examined by scanning electron microscopy (SEM).     

Synthesis,Characterization, and Micellization Behavior of Cationic Surfactants: n-Alkyl-3-Methylpyridinium Bromides and Their Drug Interaction Study by UV–Visible Spectroscopy and Conductometry

The synthesis of new cationic surfactants i.e., n-hexyl-3-methylpyridium bromide ( a ) and n-octyl-3-methylpyridium bromide ( b ), and their characterization using multinuclear nuclear magnetic resonance spectroscopy (NMR) (¹H, ¹³C) and Fourier-transform infrared spectroscopy (FT-IR) spectroscopic techniques were reported. The micellization behavior of the synthesized surfactants was studied using conductometry and ultraviolet–Visible spectroscopy. The critical micelle concentration (CMC) of compounds a and b was found to be 0.41 and 0.35 m mol L⁻¹, respectively. The effect of temperature on the CMC of these compounds was examined in the range of 298–318 K and thermodynamic parameters (ΔG, ΔH, and ΔS) of the micellization process were calculated. The antibacterial study of the synthesized surfactants revealed their strong activity against different bacterial strains. Moreover, the interaction of drugs i.e., flurbiprofen and ketoprofen, with the synthesized surfactants was investigated for gaining insights into the role of micelles as drug-delivery devices. Drug–surfactant interactions were also confirmed via a conductometric method.     

Comparison of poly(ethylene-co-acrylic acid) loaded Zn2+–montmorillonite nanocomposites and poly(ethylene-co-acrylic acid) zinc salt

Novel nanocomposite films based on poly(ethylene-co-acrylic acid) (PEAA) and zinc montmorillonite (Zn²⁺–MMT) were fabricated using a solution casting method with water as the solvent. Transmission electron microscopy indicated that Zn²⁺–MMT was distributed finely in the PEAA matrix. X-ray diffraction indicated that an ion exchange process occurs between Zn²⁺–MMT and PEAA. The nanocomposites filled with a low Zn²⁺–MMT loading increased the tensile strength and elongation at break. The significant improvements in these mechanical properties were attributed to the fine dispersion of Zn²⁺–MMT in the polymer and the covalent interaction between the polymer chains and Zn²⁺ cations. Thermogravimetric analysis and differential thermal calorimetry confirmed that PEAA formed a network through the presence of Zn²⁺ cations. A poly(ethylene-co-acrylic acid) zinc salt (PEAAZn) film by hot pressing was introduced for comparison. Zn²⁺–MMT improved the mechanical properties of the PEAA significantly compared to that of PEAAZn.     

Preparation and Characterization of α-(Fe, Al)2O3 Solid Solutions by Sol–Gel Method

The aim of this paper is to synthesize α-(Fe, Al)₂O₃ solid solutions from precursors prepared by the sol–gel method. The powders were characterized by X-ray diffraction, particle size analysis and TGA-DSC. The results indicated that the precursor prepared by sol–gel method will translate into α-(Fe, Al)₂O₃ solid solutions after calcined at 1300 °C for 3 h, with the average grain size of 14 μm. And Fe₂O₃ reduced the temperature of the γ-Al₂O to α-Al₂O₃ phase transition from 1,300 to 850 °C.     

Preparation and properties of <Emphasis Type="Italic">α</Emphasis>-phenylcinnamylideneacetylated poly(2-hydroxyethyl methacrylate)

A photosensitive polymer, -phenylcinnamylideneacetylated poly(2-hydroxyethyl methacrylate) (poly(HEMA)), was synthesized and characterized. Light irradiation upon the photosensitive poly(HEMA) film induced gel formation via dimerization between the pendent -phenylcinnamylideneacetylates of the polymer. The gel content of the crosslinked polymer increased with increasing irradiation time and reached 60% when irradiated for 30 minutes. Correspondingly, the water content decreased from 27% to 18% with irradiation time increasing from 0 to 30 minutes. The solute permeability of the -phenylcinnamylideneacetylated poly(HEMA) without irradiation is about the same as that of the poly(HEMA) film. The crosslinked -phenylcinnamylideneacetylated poly(HEMA) film prepared by light irradiation had much lower permeability as compared with the non-crosslinked film. More specifically, the photocrosslinked film had the permeability of 5.37 × 10^–7 cm/s, 1.32 × 10^–7 cm/s and 0.53 × 10^–7 cm/s for p-nitrophenol, tryptophan and flurbiprofen, respectively. This photosensitive -phenylcinnamylideneacetylated poly(HEMA) provides a new base material for fabricating poly(HEMA) hydrogel.     

Studies on uptake behavior of Hg(II) and Pb(II) by amine modified glycidyl methacrylate–styrene–N,N′-methylenebisacrylamide terpolymer

The removal of mercury and lead ions from aqueous solutions investigated by ethylenediamine, diethylenetriamine and tetraethylenepentamine functionalized polymeric adsorbent. The adsorbent was prepared by amination of terpolymer synthesized from glycidylmethacrylate, styrene and N,N′-methylenebisacrylamide. In the single metal species system (only mercury or lead ions are present) poly(glycidylmethacrylate–ethylenediamine) (PGMA–EDA), poly(glycidylmethacrylate–diethylenetriamine) (PGMA–DETA), and poly(glycidylmethacrylate–tetraethylenepentamine) (PGMA–TEPA) were found to adsorb lead or mercury ions with a slightly higher adsorption uptake capacity for lead than mercury ions. Among the three functionalized polymers poly(glycidylmethacrylate–diethylenetriamine) (PGMA–DETA) shows faster and higher adsorption capacity than poly(glycidylmethacrylate–ethylenediamine) (PGMA–EDA), poly(glycidylmethacrylate–tetraethylenepentamine) (PGMA–TEPA). The natural pH of both the metal ions was found to be most suitable for uptake. The uptake of Hg(II) and Pb(II) ions was investigated by using batch technique. The maximum adsorption capacities of Pb ions were predicted to be 4.74, 4.76 and 4.73 mmol/g and the maximum Hg(II) ion uptakes were found to be 4.76, 4.80 and 4.21 mmol/g respectively for PGMA–EDA, PGMA–DETA and PGMA–TEPA resins at their natural pH. The uptakes of Hg(II) and Pb(II) ions on the resins were found to follow Langmuir adsorption isotherm and pseudosecond order kinetics.     

Investigation of liquid–liquid equilibrium of the ternary system(water +1,6-diaminohexane + 2-methyl-1-propanol or 3-methyl-1-butanol) at different temperatures

In this study, the LLE data of ternary system (water+1,6-diaminohexane+2-methyl-1-propanol) and (water+1,6-diaminohexane+3-methyl-1-butanol) were measured at 293.15, 303.15 and 313.15 K under atmospheric pressure. Reliability of the experimental tie-line data was checked by empirical Hand, Othmer-Tobias and Bachman equations. Distribution coefficient (D) and selectivity (S) were calculated in order to investigate capability of the studied organic solvents for 1,6-diaminohexane extraction. The high values of separation factors demonstrated that 2-methyl-1-propanol and 3-methyl-1-butanol were applicable for this purpose. The experimental data were correlated by nonrandom two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) models. The percent-root-mean-square deviation (RMSD) values for NRTL and UNIQUAC models were less than 0.15, which indicated that the experimental data have been sufficiently correlated.     

Temperature influence and CO2 transport in foaming processes of poly(methyl methacrylate)–block copolymer nanocellular and microcellular foams

Fabricated by high-pressure or supercritical CO₂ gas dissolution foaming process, nanocellular and microcellular polymer foams based on poly(methyl methacrylate) (PMMA homopolymer) present a controlled nucleation mechanism by the addition of a methylmethacrylate–butylacrylate–methylmethacrylate block copolymer (MAM), leading to defined nanocellular morphologies templated by the nanostructuration of PMMA/MAM precursor blends. Influence of the CO₂ saturation temperature on the foaming mechanism and on the foam structure has been studied in 90/10 PMMA/MAM blends and also in the neat (amorphous) PMMA or (nanostructured) MAM polymers, in order to understand the role of the MAM nanostructuration in the cell growth and coalescence phenomena. CO₂ uptake and desorption measurements on series of block copolymer/homopolymer blend samples show a competitive behavior of the soft, rubbery, and CO₂-philic block of PBA (poly(butyl acrylate)) domains: fast desorption kinetics but higher initial saturation. This competition nevertheless is strongly influenced by the type of dispersion of PBA (e.g. micellar or lamellar) and a very consequent influence on foaming.CO₂ sorption and desorption were characterized in order to provide a better understanding of the role of the block copolymer on the foaming stages. Poly(butyl acrylate) blocks are shown to have a faster CO₂ diffusion rate than poly(methyl methacrylate) but are more CO₂-philic. Thus gas saturation and cell nucleation (heterogeneous) are more affected by the PBA block while cell coalescence is more affected by the PMMA phases (in the copolymer blocks + in the matrix).     

Synthesis and Characterization of New Metal–Organic Frameworks Based on Tetracyanoplatinate(II) and N,N′-bis(2-hydroxyethyl)ethylenediamine: Single Crystal Structures of ZnII and CdII Complexes Along with Magnetic Properties of NiII and CuII Complexes

Characterization and synthesis of novel cyano bridged coordination compounds [Ni(bishydeten)Pt(CN)₄] (1), [Cu(bishydeten)Pt(CN)₄] (2), [Zn(bishydeten)Pt(CN)₄] (3), [Cd(bishydeten)Pt(CN)₄] (4) [bishydeten = N,N′-bis(2-hydroxyethyl)ethylenediamine (C₆H₁₆N₂O₂)] were reported herein. The IR spectra of these coordination compounds verified the formation of aforementioned complexes. The ground state of the paramagnetic electron in the Cu^II located in tetragonal distorted octahedral sites (D _4h ) was found to be d_x2−y2 for complex 2. As for complex 1, an EPR signal was not observed because of diamagnetic property of the Pt^II and momentary relaxation times of the Ni^II. All complexes followed identical decomposition mechanism in thermal analysis and thermal stabilities of complexes changed in the order of 1 > 4 > 3 > 2. Both 3 and 4 exhibit polymeric structure according to X-ray single structure analysis. While bishydeten coordinated with three donor atoms (N,N′, and O) in complex 3, it acts as a bidentate ligand (N, and N′) in complex 4. Magnetic properties of complexes 1–2 at 15–300 K temperature range were determined as antiferromagnetic with Weiss constants = −2.619 and −0.847 K respectively.