Sodium Montmorillonite Nanoclay Research Articles

Investigation of lightweight gypsum based on montmorillonite nanoclay with enhanced insulation properties

PurposeNowadays, thermal comfort plays a prominent role in contemporary construction practices. Appropriate thermal insulation not only offers energy efficiency benefits in buildings but also enhances occupant well-being, comfort, and productivity. Therefore, a comprehensive understanding of the thermal properties of building materials is essential. This research aims to prepare and investigate a lightweight gypsum-based composite incorporating nano montmorillonite with advanced thermal insulation properties, considering both quality and cost-effectiveness while ensuring environmental compatibility.Design/methodology/approachThis study adopts a laboratory experimental approach. A gypsum sample (without additives) and seven samples of gypsum combined with varying percentages of sodium and calcium montmorillonite nanoclays undergo extensive testing and analysis. Subsequently, the properties of these samples are compared.FindingsThe results indicate that adding montmorillonite nanoclays to gypsum composites reduces the density of the tested samples and increases their porosity. Moreover, the thermal conductivity coefficient decreases in these samples, significantly improving the thermal insulation properties of the lightweight gypsum plaster. This improvement is more pronounced in samples containing sodium montmorillonite nanoclay compared to calcium-based samples. Additionally, the investigations reveal that compressive strength decreases with the addition of montmorillonite to the samples.Originality/valueIn this research, laboratory experiments were conducted to investigate the physical and mechanical properties of gypsum plaster with varying percentages of sodium and calcium montmorillonite nanoclays. The studied properties include density, porosity, thermal conductivity coefficient, and compressive strength. Additionally, stress-strain diagrams, elastic modulus, and initial and secondary critical stresses were analyzed for each specimen.

Linear and nonlinear optical parameters of biodegradable chitosan/polyvinyl alcohol/sodium montmorillonite nanocomposite films for potential optoelectronic applications

Innovations in sophisticated optoelectronic devices have increased interest in high-refractive index polymers. Herein, we report innovative nanocomposite films with high linear and nonlinear refractive indices prepared by casting chitosan (Cs) with polyvinyl alcohol (PVA) (50:50 wt%) along with different concentrations (10–50 wt%) of sodium montmorillonite (NaMMT) nanoclay. The refractive indices in addition to other optical parameters of homopolymers and hybrid materials were investigated by UV–Vis. spectroscopy and optical modeling to assess their potential applications in optics. Besides, the structure, morphology, and thermal stability of the prepared films were investigated by a multitude of experimental techniques including X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM), and thermogravimetric analysis (TGA/DTG). The ATR-FTIR, XRD, SEM, and AFM measurements confirmed the complete exfoliation of NaMMT nanolayers in the Cs/PVA matrix. The TGA/DTG revealed an increase in the thermal stability of Cs/PVA film with increasing clay content. The UV–Vis. measurements revealed a decrease in the optical energy gap (Eg) and a substantial increase in the linear (nD) and nonlinear (n2) refractive indices as clay content increased. Additionally, the nanohybrids displayed low UV transmission and reflected about 80 % of UV rays, making them excellent candidates for UV protection. For the first time, the dissipation factor (tanδ) in the UV/Vis. region has been calculated and fitted with the Drude-Lorentz model to predict the plasma frequency (ωp), resonance frequency (ω0), and electron lifetime (τ) of pristine polymers and nanocomposites.

Determination of vanillin in different food samples by using SMM/Au@ZIF-67 electrochemical sensor

Vanillin is a popular flavoring agent in many food products. Simple, fast, and reliable quantification of this compound is crucial for the food industry. In this work, we have developed a new electrochemical sensor for accurate detection of vanillin in various real samples. The composite electrode was made of sodium montmorillonite nanoclay (SMM) and gold nanoparticles modified ZIF-67 (Au@ZIF-67), in which SMM contributes to the large adsorption capacity of the analyte, ZIF-67 and SMM supply more sensing active sites, and gold nanoparticles provide high electrical conductivity. The sensing electrode was comprehensively characterized using Brunauer–Emmett–Teller, EDS, XRD, SEM, FTIR, and TEM, and its electrochemical behavior for determination of vanillin including the electrooxidation mechanism of vanillin and different parameters such as scan rate and pH value was investigated. The result revealed that a two electron-two proton process was involved in the electrooxidation of vanillin, which takes place more readily due to the lower potential on the surface of SMM/Au@ZIF-67/carbon paste electrode. The new composite electrode was also more sensitive to vanillin detection with an anodic peak current almost 2.6 times more than that of the bare electrode. A linear sensing concentration range was established between 1 and 1200 nM with a detection limit of 0. 3 nM and a limit of quantitation of 1 nM. For real samples, the sensor demonstrated excellent recovery rates and reliability that was comparable to the standard high-performance liquid chromatography method.

Synthesis of copolymer nanocomposite by in situ intercalative polymerization for batch and fixed bed adsorption

AbstractPartially neutralized acrylic acid (AA)/sodium acrylate (NaAA) and N, N′‐methylenebisacrylamide (MBA) were subjected to intercalative copolymerization in aqueous solution of polyvinyl alcohol (PVA) in the presence of sodium montmorillonite (NaMMT) nano clay to prepare filled semi‐interpenetrating network (FSIPN) type composite polymer networks. Filled Full IPN (FFIPN) composites were prepared in a similar way by additional crosslinking of PVA with maleic acid (MA) crosslinker. The polymers were characterized with FTIR, NMR, XRD, TGA, SEM, EDAX, TEM, XPS, DLS, PZC, and pH reversibility test. The synthesis variables were optimized with respect to batch adsorption of 100 mg/L each of methyl violet (MV) and congo red (CR) dye as response using the central composite design (CCD) of response surface methodology (RSM). The FFIPN prepared from polyacrylic acid (PAA)/sodium polyacrylate containing PVA/Clay/MBA/MA of optimized composition of 4/1.5/0.75/4 (wt.% of AA/NaAA), respectively, showed an optimized adsorption (mg/g adsorbent) of 459.16/417.31 of MV/CR as single dye and 438.01/417.31 of MV/CR in 1:1 binary mixtures of 100 mg/L feed concentration. The FFIPN showed an adsorption (mg/g) of 41.54/37.61 and removal% of 88.5/80.12 at a feed flow rate, bed height, and feed inlet concentration of 20 mL/min, 20 mm, and 50 mg/L, respectively.

Influence of sodium-montmorillonite nanoclay on flammability, thermal stability, morphology, and mechanical properties of rigid water-blown palm oil-based polyurethane foam

This paper presents the experimental works on rigid palm oil-based polyurethane (PU) foam reinforced with sodium-montmorillonite (Na-MMT). Filler loading was varied between 1 and 10 wt %., and the obtained foam was characterized for its combustibility, morphology, thermal stability, and mechanical response. Exfoliated clay microstructure was exhibited at lower Na-MMT loadings. Addition of nanoclay into the PU foam failed to impart any discernable improvement with regards to its flammability, believed due to stronger influence of low-functionality palm oil polyol used. Apparent improvement in thermal stability was observed at low clay amounts. Foam with finer cell size was obtained in the presence of Na-MMT, however only until a certain loading limit. Compressive strength generally increases with increasing clay content, but after 3 wt % the property deteriorated. Peculiarly, compressive strength rose again at 5 wt % and 6 wt % – postulated due to additional load-bearing effect of ‘integral skin’ – before plummeting back again beyond this value.

Pembuatan dan Karakterisasi Biodegradable plastic Berbasis Campuran Pati dan Selulosa Dari Limbah Jagung

Foodstuffs need proper packaging to prevent spoilage. The use of conventional plastics for packaging has caused environmental problems. It is necessary to develop environmentally friendly packaging as biodegradable plastic. The purpose of this study was to isolate cellulose from corn cobs with three different procedures to determine the best procedure for producing cellulose, as evidenced by the color and results of FTIR analysis. The best cellulose yields are used to make biodegradable plastic films combined with starch and a glycerol plasticizer, sodium montmorillonite nanoclay filler, and clove leaf essential oil. The film that has been made is continued with characterization in the form of analysis of degradation ability, analysis of volatility mass fraction (%), analysis of swelling degree (%), and water solubility (%). The results of this study found that the best cellulose isolation was produced by a procedure 2. The results of the analysis of the degradation ability of the film showed that it was under SNI 7188.7: 2016 with the fastest degradation results within four days with the addition of SMMT. The results of the VMF (%) analysis showed that the presence of EO and SMMT in the composition causes the VMF (%) value to be below. The results of the SD (%) analysis show that the presence of SMMT causes the SD (%) value to increase while the addition of EO causes the SD (%) value to decrease. The results of the WS (%) analysis showed that the presence of SMMT causes the WS (%) to increase, while the addition of EO to the composition variation causes the WS (%) to decrease

SYNTHESIS AND STRUCTURAL PROPERTIES OF CHITIN/CLAY BIO-NANOCOMPOSITES

Chitin, which is composed of 2-acetamido-2-deoxy-D-glucopyranose (N-acetyl-D-glucosamine) units linked by β-(1,4) linkage, makes up the cell walls of fungi, the exoskeletons of arthropods, such as crustaceans (e.g., crabs, lobsters and shrimps) and insects, the radulae of mollusks, and the beaks of cephalopods, including squid and octopuses. Both chitin and clay are sustainable materials, as they are low cost, biodegradable and readily available. That is why, in this study, sodium montmorillonite (CNa) nanoclay and 1-140 (C15A) organo-nanoclay were used as nanofiller support in the preparation of chitin/clay bio-nanocomposites. Trichloroacetic acid was used to dissolve the chitin and to disperse the clay in the chitin solution. Chitin/CNa and chitin/C15A bio-nanocomposites were synthesized by the solution-induced intercalation method. The effect of the nanofiller on the bio-nanocomposite was investigated by varying the loading rates as follows: 1, 3 and 5% by weight. The composites were characterized by FT-IR, XRD and SEM methods. The XRD patterns and SEM images showed that the clay dispersion in the chitin biopolymer matrix presented an exfoliated structure. It was noted that neither the nanoclay nor the organo-nanoclay used in the synthesis of the bio-composites affected the formation of the exfoliated structure. This result can be attributed to the use of a low amount of clay. These newly synthesized bio-composites, which are environmentally friendly and sustainable, can find application in many different areas in the future.

Simultaneous Removal of Heavy Metals from Wastewater Using Modified Sodium Montmorillonite Nanoclay.

Sodium montmorillonite nanoclay particles were modified by 3-aminopropyltrimetoxysilane using a physical vapor deposition method and applied for the simultaneous removal of Cd, Zn, Pb and Ni heavy metals from wastewater samples. Experiments were performed in both batch and column systems. Several parameters that influence the removal efficiency, such as the pH, contact time, amount of adsorbent, interfering ions, flow rate of sample passage and eluent solvent, were evaluated and optimized. The results showed that the adsorption isotherms obeyed Langmuir isotherms for all heavy metals. Also, interfering ions did not influenced the removal efficiency. Finally, modified nanoclay successfully could remove all heavy metals from real wastewater samples to near completeness.

Impact of unmodified (PGV) and modified (Cloisite20A) nanoclays into biodegradability and other properties of (bio)nanocomposites

The production of bionanocomposites using nanoclays are in constant development to improve the mechanical, gas barrier and thermal properties, and the biodegradability of the polymeric materials. In this study, two different nanoclays: non-treated (hydrophilic sodium-montmorillonite nanoclay - PGV) and treated with organo-modification (montmorillonite nanoclay - Cloisite 20A) were incorporated (2%wt.) into PBAT [poly(butylene adipate-co-terephthalate)] by melting process. The composites properties were evaluated by SEM/EDS, XRD, mechanical properties, contact angle, TGA, and aerobic biodegradation (Sturm test). The SEM/EDS showed the presence of sodium in PGV, which characterize it as sodic montmorillonite, while the Cloisite 20A, as montmorillonite organo-modified, by the high occurrence of carbon percentage. The patterns of X-ray diffraction (XRD), about the d-spacing of the bionanocomposites, indicates high intercalation of the matrix with nanoclay Cloisite 20A and a decrease in the crystallinity index. The elasticity modulus of the bionanocomposites had a slight increase, while maximum elongation was decreased, corroborating with the intercalation, as seen in XRD results. The contact angle results have shown high hydrophilicity for PBAT/PGV, by the presence of sodium ions. Besides, an increase in thermal stability for PBAT/Cloisite 20A was observed. However, the CO2 produced during the degradation of the PBAT/PGV was higher than PBAT/Cloisite20A only at the beginning of the process. Besides, better exfoliation of nanoclay Cloisite 20A in PBAT promoted an increase in the biodegradation process rate. Therefore, these properties can contribute to possible soil stabilizer application, hitching surface hydrophilicity, and good biodegradability, by its water retention ability.

Improving the Flexural Properties of E-Glass Fibers/Epoxy Isogrid Stiffened Composites through Addition of 3-Glycidoxypropyltrimethoxysilane Functionalized Nanoclay

This research work investigates the effect of silane functionalized nanoclay on the flexural response of E-glass/epoxy isogrid stiffened composite (IGSC). To do so, the sodium montmorillonite nanoclay were functionalized by 3-glycidoxypropyltrimethoxysilane as a silane coupling agent. In the following, by using the mechanical stirrer and ultrasonic waves, the surface functionalized nanoclay particles with the different weight percentages (0, 1, 3, and 5 wt.%) were dispersed into the epoxy resin. After that, the IGSC panels containing the functionalized nanoclay were made by combining the filament winding and hand lay-up methods. By using the Fourier transform infrared (FT-IR) analysis, the functionalizing trend of nanoclay particles was characterized. It was realized that by adding 5 wt.% functionalized nanoclay to IGSC, the flexural load, flexural stiffness and energy absorption of that were reached to 1402 MPa, 82.6 N/mm and 233.9 J/kg, respectively, which were the maximum improvement of those properties. By using electron microscopy examinations from the fracture surfaces of IGSC structures, it was found that the presence of silane functionalized nanoclay particles improved the interfacial adhesion between the epoxy matrix and E-glass fibers.

Surface Modification of Sodium Montmorillonite Nanoclay by Plasma Polymerization and Its Effect on the Properties of Polystyrene Nanocomposites

Sodium montmorillonite nanoclay (Na+-MMT) was modified by plasma polymerization with methyl methacrylate (MMA) and styrene (St) as monomers and was denominated as Na+-MMT/MMA and Na+-MMT/St, respectively. This plasma modified nanoclay was used as reinforcement for polystyrene (PS) nanocomposites that were prepared by melt mixing. Pristine and modified Na+-MMT nanoclay were analyzed by the dispersion in various solvents, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results confirmed a change in hydrophilicity of the modified Na+-MMT, as well as the presence of a polymeric material over its surface. The pristine PS/Na+-MMT and modified PS/Na+-MMT/MMA and PS/Na+-MMT/St nanocomposites were studied with X-ray diffraction (XRD), differential scanning calorimetry (DSC), and TGA, as well as mechanical properties. It was found that the PS/Na+-MMT/St nanocomposites presented better thermal properties and an improvement in Young’s modulus (YM) in compared to PS/Na+-MMT/MMA nanocomposites.

Silane functionalization of sodium montmorillonite nanoclay: The effect of dispersing media on intercalation and chemical grafting

Abstract This study investigated the effect of various dispersing media on the silane functionalization of sodium montmorillonite nanoclay (Na Mt) to evaluate each medium's effectiveness on the intercalation and chemical grafting of silane coupling agent. The amount of intercalation was estimated using the equation that was developed in our previous work based on thermogravimetric analysis. The results showed that the amount of silane intercalation was the greatest for water and glycerol media (≈1.582 mmol/g clay and ≈1.480 mmol/g clay, respectively), which was in agreement with the d001-values calculated by the XRD analysis (≈19.6 A and ≈14.4 A, respectively). 29Si NMR results showed a new T site in addition to Q peaks for all modified nanoclays in different dispersing media, indicating the occurrence of silane chemical grafting at the surface of the nanolayers. The A T 3 A Q 3 in NMR spectra was used to compare the amount of chemically grafted silane in different dispersing media, a new approach for Mt material. Hydrogen-bonding solvents (water, glycerol and ethanol), and polar solvents (DMF and THF) showed greater T3 peak intensities compared to other dispersing media, indicating higher amounts of chemical grafting of silane molecules. This observation was in agreement with the broadening of FTIR peak at 1130–1000 cm− 1, which is explained by the formation of extra Si O Si bonds; that is, in turn, due to silane chemical grafting at the surfaces of the nanolayers. The silane-nanofiller interactions were correlated with the Hansen solubility parameters of different dispersing media used for the modification. This research has potential to help design and improve the nanoclay modification processes, which are used in the fabrication of clay-polymer nanocomposites.

Dye removal from aqueous solutions using novel nanocomposite hydrogel derived from sodium montmorillonite nanoclay and modified starch

A novel nanocomposite hydrogels (NCHs)-based polysaccharide was synthesized by incorporating Na-montmorillonite (NaMMT) nanoparticles (NPs) into poly acrylic acid and polyacrylamide grafted onto starch [P(AA–AAm)-g-starch] hydrogel. The conditions applied in this synthesis were optimized using the Taguchi orthogonal experimental design method. The characterization of NaMMT NPs/P(AA–AAm)-g-starch NCH was performed by Fourier transform infrared, thermogravimetric analysis, scanning electron microscopy/energy-dispersive X-ray, and atomic force microscopy analyses. The resulting optimized NCH showed improved pH-dependent swelling and enhanced safranin adsorption capacity compared to pure hydrogel and NaMMT NPs. Its adsorption process could be described very well by pseudo-second-order and Elovich kinetic models. The adsorption isotherm was followed by Freundlich isotherm models. The conclusion confirms the prospect of NCH as an effective adsorbent for the adsorption of dyes from aqueous solutions.

Fabrication of a novel, sensitive and selective electrochemical sensor for antibiotic cefotaxime based on sodium montmorillonite nonoclay/electroreduced graphene oxide composite modified carbon paste electrode

A novel, simple, sensitive and selective sensor based on carbon paste electrode (CPE) modified by Sodium Montmorillonite nanoclay (NaMM)/Electroreduced Graphene Oxide (ERGO) Composite was developed for the electrochemical determination of Cefotaxime (CEF). The electrooxidation of CEF was studied on modified carbon paste electrode using cyclic voltammetry and differential pulse voltammetry as diagnostic techniques. It was found that the oxidation peak current of CEF on the modified carbon paste electrode was greatly improved compared to that obtained on the unmodified carbon paste electrode. The electronic transfer property of the NaMM/ERGO/CPE was characterized by electrochemical impedance spectroscopy (EIS). Also, morphology of NaMM and ERGO were characterized by scanning electron microscopy (SEM). Under optimized conditions, the modified electrode exhibited a linear response over two linear concentration ranges from 0.5 to 40nM and 40 to 2400nM CEF, with a detection limit of 0.1nM. The proposed sensor was successfully applied for monitoring of CEF in serum and urine samples and satisfactory results were obtained.

Silane functionalization of sodium montmorillonite nanoclay and its effect on rheological and mechanical properties of HDPE/clay nanocomposites

The present research reveals novel results about the silane functionalization of sodium montmorillonite (Na-Mt) by comparing the interlayer space and thermal stability of the nanofiller at different initial silane concentrations. XRD and TGA results indicate an increased d001 and a high thermal stability for the silane-modified Na-Mt, which makes it a promising nanofiller for polymer nanocomposites. The amounts of intercalation and chemical grafting are estimated from TGA results using equations developed in this work; the silane intercalation is found to be the highest (0.504mmol/g clay) for 9mmol/g clay initial silane concentration, which is consistent with the d001-value (22.6Å). Intercalation increases with increase in initial silane concentration up to 9mmol (intercalated amount≈0.504mmol/g clay), then decreases at higher concentrations, e.g., 15mmol silane have an intercalated amount of 0.405mmol/g clay. However, the chemical grafting value for 15mmol silane is greater (0.18mmol/g clay) relative to that of the 9mmol silane initial concentration (0.15mmol/g clay). This can be explained by the occurrence of the side reactions at the edges for 15mmol silane, which reduces the intercalation amount. The rheological and tensile properties of HDPE/silane functionalized clay suggest that the storage modulus, damping factor and mechanical behavior of the composites depend on the clay nanofiller, as well as the nanocomposite preparation procedure (i.e. masterbatch technique). The tensile modulus showed ~15% enhancement for 85%HDPE/15%PEMA/2% modified clay over the pure polymer. TEM images revealed a well-dispersed clay structure for the HDPE/2wt% modified-clay/PEMA nanocomposite that is prepared through the masterbatch technique.

Influence concentration of modifying agent on properties of natural rubber/organoclay nanocomposites

Sodium-montmorillonite (Na-MMT) nanoclay was modified with different concentrations of octadecylamine organic modifying agent at 0.5, 1.0 and 1.5 times the CEC of Na-MMT. Influence of concentration of modifying agent on properties of the organoclays and natural rubber/organoclay nanocomposites was investigated. It was found that the optimum concentration of modifying agent was 1.5 times the CEC of Na-MMT. That is, at this concentration, larger d-spacing of organoclay particles and higher degree of clay dispersion in natural rubber matrix were observed. Larger interlayer d-spacing also caused enhancement of the mechanical properties of the NR/organoclay nanocomposites. Additionally, the NR/organoclay nanocomposites with higher concentration of modifying agent exhibited faster curing reaction with higher crosslink density. Furthermore, the organoclays with larger d-spacing and higher degree of dispersion in the natural rubber matrix exhibited enhancement of the mechanical and dynamic properties and thermal stability of natural rubber/organoclay nanocomposites.

Fast and Efficient Adsorption of Ag Nanoparticles by Sodium Montmorillonite Nanoclay from Aqueous Systems

Silver nanoparticles (AgNPs) are, due to their antimicrobial properties, the most widely used nanoparticles in commercial products. AgNPs are incorporated into medical products such as bandages, as well as in textiles and household items. Besides its antimicrobial effect, exposure to soluble silver compounds produce toxic effects on all living organisms. In this work, the removal of Ag nanoparticles (AgNPs) using aqueous sodium montmorillonite nanoclay in the presence of a cationic surfactant stabiliser was investigated. The effects of experimental parameters on the adsorption process, such as pH, surfactant concentration, adsorbent dosage, initial AgNPs concentration and contact time, were studied. The Langmuir and Freundlich isotherm models were applied and the Langmuir model was found to best fit the equilibrium isotherm data. Langmuir adsorption capacity was found to be 71.4 mg g−1 of AgNPs at pH 7. The results indicate that sodium montmorillonite nanoclay can be used for the fast and efficient removal of AgNPs from aqueous solutions.

Study on adsorption of cationic dye on novel kappa-carrageenan/poly(vinyl alcohol)/montmorillonite nanocomposite hydrogels

In this study, novel kappa-carrageenan/poly(vinyl alcohol) nanocomposite hydrogels were developed by incorporating sodium montmorillonite nanoclay. The mixture of polymers and montmorillonite was crosslinked with freezing–thawing technique and subsequent with K+ ions. The structure of nanocomposite hydrogels was characterized with the FTIR, SEM, XRD, and TEM techniques. By introducing montmorillonite nanoclay, the swelling capacity of nanocomposites was decreased from 1200 to 320 % due to the crosslinking role of montmorillonite nanoclay. The adsorption of cationic crystal violet dye on nanocomposite hydrogels was studied via batch adsorption system on the subject of contact time, nanoclay content, pH of dye solution, temperature, and ion strength of dye solution. Compared with clay-free hydrogel, the nanocomposites indicated a relatively improved adsorption capacity at the same batch system. The variation in the pH of initial dye solution had no significant effect on dye adsorption capacity of hydrogels. Study on salinity of dye solutions showed that while the NaCl salt had less effect on adsorption capacity of hydrogels, in the presence of CaCl2 and AlCl3 salts, the adsorption capacity of nanocomposites was significantly decreased. The adsorption kinetics of crystal violet on hydrogels was well described by the pseudo-second-order model. Also, the equilibrium dye adsorption data were analyzed with non-linear Langmuir and Freundlich models and the equilibrium process was followed well the Langmuir model. According to the Langmuir model, the maximum adsorption capacity of nanocomposites was obtained 151 mg g−1. Thermodynamic parameters confirmed the spontaneity of the adsorption process. Therefore, the synthesized hydrogel nanocomposites could be employed as a low-cost adsorbent in the removal of dyes from aqueous solution.

Construction of a sensitive sensor for D-penicillamine using sodium montmorillonite nonoclay as a modifier

A carbon paste electrode modified with Sodium montmorillonite nanoclay (SMMT) was prepared and used for study and low level determination of D-penicillamine (D-Pen) using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Compared with the unmodified carbon paste electrode, the modified electrode facilitated the electron transfer of D-Pen, since it notably increased the oxidation peak current of drug. The electronic transfer property of the SMMT carbon paste electrode was characterized by electrochemical impedance spectroscopy (EIS). Also, morphology of the electrode was characterized by scanning electron microscopy (SEM). Under optimized conditions, the modified electrode exhibited a linear response over the concentration range of 1–1000μM D-Pen, with a detection limit of 0.3μM. The proposed sensor exhibited a high sensitivity, good selectivity and was successfully applied for D-Pen determination in a D-Pen capsule.

Interpenetrating polymer networks (IPN) based on gelatin/poly(ethylene glycol) dimethacrylate/clay nanocomposites: Structure–properties relationship

The effects of cross-linking sequence (simultaneous or sequential) and incorporation of exfoliated sodium-montmorillonite (Na+-MMT) nanoclay on the structure and properties of interpenetrating polymer networks (IPNs) based on gelatin/poly(ethylene glycol)dimethacrylate were studied by means of different complementary techniques. Gelatin and PEGdmA phases were cross-linked via chemical and in-situ UV curing, respectively. 2,2-dimethoxy-2-phenylacetophenone (DMPA) (1.5% w/w) was used as photo-initiator to cross-link PEGdmA. The results showed that the incorporation of small amount of Na+-MMT nanoplatelets accelerates the kinetics of chemical cross-linking of gelatin by glutaraldehyde (1.0% w/w). This led to a new hypothesis concerning the tuning structural evolution of the IPNs by the Na+-MMT content. In the case of simultaneous IPNs, in which both phases cross-linked at the same time, the accelerated cross-linking of gelatin in the presence of exfoliated sodium-montmorillonite led to increased structural homogeneity, improved mechanical and thermal properties. Incorporation of nanoclay did not show any significant effect on the structure and properties of the IPNs synthesized via sequential method in which gelatin and PEGdma phases were cross-linked separately. For the semi-IPNs, however, Na+-MMT induced macroscopic phase separation and resulted in lower mechanical properties. These results might shed light on the mechanisms underlying structure–property relationship in biohybrid IPNs based on gelatin as promising candidates for tissue engineering and drug delivery applications.