Presence Of Dioctyl Phthalate Research Articles

Effect of montmorillonite addition (modified and unmodified) on the structural, mechanical, thermal, and morphological properties of nanocomposites based poly (vinyl chloride)

Poly (vinyl chloride)/ montmorillonite nanocomposites were prepared using a melt mixing technique. For this purpose, three montmorillonite samples (MMT) namely, raw montmorillonite (R-MMT), sodium montmorillonite (Na+-MMT) and organically modified montmorillonite (O-MMT) were used with different contents (0, 1, 3, 5, 7 and 9 phr) in the presence of dioctyl phthalate (DOP). X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM), Differential Scanning Calorimetry (DSC), and mechanical testing were used to investigate the physical properties of nanocomposites (PVC/MMT). The results of XRD show that macromolecule chains of PVC may be intercalated or exfoliated into the gallery of modified montmorillonite (Na+-MMT and O-MMT). Microcomposites structure is formed on the PVC/R-MMT nanocomposites when the unmodified montmorillonite (R-MMT) content is added from 1 to 9 phr. However, the glass transition temperature (Tg) of PVC/O-MMT nanocomposites is shifted slightly to lower temperatures. Furthermore, O-MMT plays the role of an internal plasticizer hence increases the distance between macromolecule chains of the polymer. Consequently, the degree of interactions between the chains decreases inducing a decrease in Tg. Synergy effect is also observed on the PVC/O-MMT nanocomposites with the increase in the amount of O-MMT. The morphological study by AFM shows a reduction in surface roughness under the effect of montmorillonite modified, and particularly with (1 phr) of O-MMT.

Bio-based furan coatings: adhesion, mechanical and thermal properties

In this study, preparation of polyfurfuryl alcohol (PFA) as a renewable binder resin with an origin in biomass conversion is reported for developing a heat-resistant coating. PFA resin was synthesized in the presence of maleic anhydride as a catalyst. Various techniques were used to characterize the synthesized PFA resin. In the second step, different coating samples were prepared using PFA resin. Flexibility, adhesion strength and thermal/curing behavior of the coating samples were investigated as a function of their compositions such as the resin, plasticizers and titanium dioxide (TiO2) contents. The coatings were cured optimally at 150 °C according to isothermal and non-isothermal DSC measurements. Leveling property of the coatings was significantly improved in the presence of TiO2 due to a corresponding increased viscosity of the compound. The adhesion strength of the coating was low due to the aromaticity of PFA chains, high cross-linking degree of the binder resin and the difference existing between thermal expansion coefficient of the coating and steel substrate. In the presence of dioctyl phthalate and long-oil alkyd resin as plasticizers, flexibility and adhesion strength of the coatings were significantly improved up to 15 mm and 2.7 MPa, respectively. High thermal stability of the coatings was supported by TGA findings but it was deteriorated in the presence of alkyd resin. Alkyd resin, a plasticizer, increased the extent of cross-linking due to the chain flexibility enhancement according to DSC and DMTA findings. Finally, a heat-resistant coating formulation containing 9.3 wt% long-oil alkyd resin and 9.3 wt% TiO2 was selected as a good candidate for heat-resistant coating development due to the highest thermal and mechanical properties shown.

A molecularly imprinted photoelectrochemical sensor based on the use of Bi2S3 for sensitive determination of dioctyl phthalate.

A molecularly imprinted polymer photoelectrochemical (MIP-PEC) sensor based on bismuth sulfide (Bi2S3) is described for the determination of the plasticizer dioctyl phthalate (DOP). Bi2S3 was used as the photoelectrical converter of the sensor, and visible light was utilized as the excitation source. The molecular imprinting film was prepared through the electropolymerization of monomers in the presence of DOP. Under optimal experimental conditions, the photoelectrochemical response was linearly proportional to the logarithm of the DOP concentration in the 0.5-70 pM DOP concentration range, and the detection limit was 0.1 pM. The method is highly stable and reproducible. It was applied to the determination of DOP in spiked water samples. Graphical abstract A novel molecularly imprinted photoelectrochemical sensor with high sensitivity and high selectivity based on Bi2S3 was developed for dioctyl phthalate detection. Bi2S3 was firstly used as a photoelectric converter in photoelectrochemical sensor to improve the sensitivity of the sensor. Combining photocurrent measurement with molecular imprinting technique makes the sensor highly selective.

All-Solid-State, PVC Membrane, and Carbon Paste Ion-Selective Electrodes for Determination of Donepezil Hydrochloride in Pharmaceutical Formulation.

All-solid-state, polyvinyl chloride (PVC) membrane, and carbon paste potentiometric ion-selective electrodes (ISEs) were proposed for the determination of donepezil hydrochloride (DON) in the drug substance and a pharmaceutical formulation. The potentiometric response toward DON was based on the existence of donepezil-tetraphenyl borate (DON-TPB) in a PVC membrane or a carbon paste in the presence of dioctylphthalate. In contrast, the solid-state electrode was prepared by direct incorporation of DON-TPB into a commercial nail varnish without external additives. The electrodes exhibited Nernstian slopes of 55.0, 57.0, and 53.0 mV/decade over the concentration ranges of 1 × 10-5 to 1 × 10-3, 1 × 10-4 to 10-2, and 1 × 10-4 to 5 × 10-3 for the solid-state, PVC membrane, and carbon paste electrodes, respectively. The response of the electrodes is independent of pH in the range of 2-≤8. The electrodes showed good selectivity for DON with respect to a number of inorganic cations and amino acids. The electrodes were used for the determination of DON in pure solution and in pharmaceutical tablets with high accuracy (±2%) and precision (RSD ≤2%). The solid-state electrode is simple, economical, and rapid when compared to the PVC membrane and carbon paste electrodes.

A novel, highly sensitive, selective, reversible and turn-on chemi-sensor based on Schiff base for rapid detection of Cu(II)

In this work, a novel optical fluoro-chemisensor was designed and synthesized for copper (II) ions detection. The sensor film is created by embedded N,N-Bis(2-hydroxo-5-bromobenzyl)ethylenediamine in poly vinyl chloride (PVC) film in presence of dioctyl phthalate (DOP) as plasticizer. The receptor Schiff base reveals “off-on” mode with high selectivity, significant sensitivity to Cu(II) ions. The selectivity of optical sensor for Cu(II) ions is the result of chelation enhanced fluorescence (CHEF). The optimal conditions of pH and response time at which higher efficiency of sensor film is performed was found to be 6.8 and 2.48min. The possible interference of other metal ions in solution was examined in presence of different types of metal ions. This film shows high selectivity and ultra-sensitivity with low detection limit LOD (1.1×10−8M). Thus, these considerable properties make it viable to monitor copper metal ions within very low concentration range (0–15×10−6M Cu(II)) and highly selective even in the presence of different types of metal ions. The sensor reversibility was achieved by utilizing EDTA solution with concentration of 0.1M solution.

Preparation of a ticlopidine potentiometric sensor and its application to pharmaceutical and biological analysis

Ticlopidine (Tic) ion selective liquid membrane electrode was constructed from poly (vinyl chloride) containing Tic-tetraphenylborate (Tic-TPB) as the sensing element in the presence of dioctylphthalate (DOP) as the plasticizing solvent mediator. The electrode shows nearly Nernstian response for the drug over the concentration range of 1.0×10−2–5.0×10−5M with cationic slope of 58.23mV per concentration decade, and the response time is very short (≤10s). The electrode potential is nearly stable over the pH range 3.8–5.4. The electrode exhibits good selectivity for the Tic with respect to a large number of inorganic ions, amino acids and some pharmaceutical substances. The sensor successfully was used for the determination of Tic in pharmaceutical and biological samples. The average recovery and RSD for the analysis of Tic in pharmaceutical and biological samples using the proposed method obtained 101.04, 98.90% and 1.14, 1.39%, respectively. The results are in good agreement with those obtained by voltammetry method.

Determination of Sodium Dodecyl Sulfate in Toothpastes by a PVC Matrix Membrane Sensor

AbstractThe construction and characteristic performance of a new potentiometric PVC membrane sensor responsive for sodium dodecyl sulfate (SDS) are described. The sensor is based on the use of cetyltrimethylammonium‐tetraphenylborate (CTA‐TPB) ion‐pair complex as electroactive material in PVC matrix in presence of dioctyl phthalate as a solvent mediator. The sensor exhibits a rapid, stable and near‐Nernstian response for SDS over the concentration range of 5 × 10−3–5 × 10−6 mol dm−3 at 25 ± 2 °C and the pH range 4–8.5 with slope of 59.6 mV/decade change in SDS concentration. The lower detection limit is 5 × 10−6 mol dm−3 and the response time is 45 s. The determination of selectivity coefficients for different anions shows there is no interference except that of dodecyl benzene sulfonate (DBS−) ion which has a strong interference. The results obtained in the determination of SDS in toothpastes, using this sensor as an indicator electrode, were compared with those obtained from the spectrophotometric method using methylene blue as the reagent.

Investigation of the Effect of DOP on Polyaniline and Polyaniline/Polystyrene Nanocomposites

Polyaniline nanocomposite was prepared in aqueous media by polymerization of aniline using ((NH4)2S2O8) as an oxidant in the presence of dioctyl phthalate (DOP). Also polyaniline/polystyrene (PAn/PS) nanocomposite was prepared in the aqueous solution by polymerization of styrene and aniline using potassium iodate (KIO3) and ammonium peroxy disulfate ((NH4)2S2O8) as oxidant in the presence of dioctyl phthalate (DOP). The PAn and PAn/PS nanocomposites were characterized in terms of morphology, chemical structure and glass transition temperature. The chemical structure, morphology and glass transition temperature of product were studied by Fourier Transform Infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and differential scanning calorimetry (DSC).

Morphology of mixed primary and secondary organic particles and the adsorption of spectator organic gases during aerosol formation

Primary organic aerosol (POA) and associated vapors can play an important role in determining the formation and properties of secondary organic aerosol (SOA). If SOA and POA are miscible, POA will significantly enhance SOA formation and some POA vapor will incorporate into SOA particles. When the two are not miscible, condensation of SOA on POA particles forms particles with complex morphology. In addition, POA vapor can adsorb to the surface of SOA particles increasing their mass and affecting their evaporation rates. To gain insight into SOA/POA interactions we present a detailed experimental investigation of the morphologies of SOA particles formed during ozonolysis of alpha-pinene in the presence of dioctyl phthalate (DOP) particles, serving as a simplified model of hydrophobic POA, using a single-particle mass spectrometer. Ultraviolet laser depth-profiling experiments were used to characterize two different types of mixed SOA/DOP particles: those formed by condensation of the oxidized alpha-pinene products on size-selected DOP particles and by condensation of DOP on size-selected alpha-pinene SOA particles. The results show that the hydrophilic SOA and hydrophobic DOP do not mix but instead form layered phases. In addition, an examination of homogeneously nucleated SOA particles formed in the presence of DOP vapor shows them to have an adsorbed DOP coating layer that is approximately 4 nm thick and carries 12% of the particles mass. These results may have implications for SOA formation and behavior in the atmosphere, where numerous organic compounds with various volatilities and different polarities are present.

Preparation and thermal and thermo‐oxidative stability of vinylidene chloride‐co‐vinyl chloride copolymer/synthetic hectorite nanocomposites

AbstractPoly(vinylidene chloride‐co‐vinylchloride)/organically modified hectorite (VDC‐VC/SPN) nanocomposites were prepared by melt blending VDC‐VC copolymer with SPN in the presence of dioctyl phthalate, which acted as a plasticizer. As a result, the exfoliated structure was found in the VDC‐VC/SPN nanocomposites. In nitrogen atmosphere, VDC‐VC/SPN nanocomposites exhibited a single‐step thermal degradation. The thermal stability of VDC‐VC/SPN nanocomposites is significantly influenced by the SPN, which was modified with long alkyl ternary ammonium salt. In air atmosphere, VDC‐VC/SPN nanocomposites revealed a two‐step thermo‐oxidative degradation behavior. At the first degradation stage, the weight loss pattern is similar to that of VDC‐VC composites in nitrogen, in which the thermo‐oxidative stability of VDC‐VC/SPN nanocomposites is affected by the ternary ammonium salt and oxygen rather than its morphology. At the second degradation stage, both the enhanced thermo‐oxidative stability and the flame‐retardation ability of VDC‐VC composites are strongly and closely related to the morphology of nanocomposites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci ,2009

Preparation and characterization of vinylidene chloride‐co‐vinyl chloride copolymer/fluorinated synthetic mica nanocomposites I thermal and mechanical properties studies

AbstractPoly(vinylidene chloride‐co‐vinylchloride)/organically modified fluorinated synthetic mica (MEE) (VDC‐VC/MEE) nanocomposites were prepared by melt blending of VDC‐VC copolymer with MEE, in the presence of dioctyl phthalate (DOP) which acted as a plasticizer and a cointercalating agent. The nanostructure, thermal, and dynamic mechanical properties of the VDC‐VC/MEE nanocomposites were studied by wide angle X‐ray diffractometer (WAXD), scanning electron microscope (SEM), transmission electron microscope (TEM), thermogravimetric analyzer (TGA), and dynamic mechanical analyzer (DMA). It was found that partially intercalated and partially exfoliated structures coexisted in VDC‐VC/MEE nanocomposities. Below 8 wt % MEE content, the intercalation effect of nanocomposites decreased with increasing the MEE content. Under a nitrogen atmosphere, VDC‐VC/MEE nanocomposites exhibited a single step thermal degradation behavior. The nanostructure of VDC‐VC/MEE can effectively prevent volatile gases from being released, and thus enhances its thermal stability. The thermal stability of VDC‐VC/MEE nanocomposites is strongly related to the morphology of nanocomposites and the degraded composites structure. DMA revealed a significant improvement in the storage modulus within the testing temperature range. The increase in storage modulus depends on the MEE content, which is attributed to the dispersed phase morphology. The glass transition temperature of VDC‐VC/MEE nanocomposites is affected by the chain mobility in the nanocomposites rather than the aggregative morphology. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1214–1225, 2008

Effect of hydrophobic primary organic aerosols on secondary organic aerosol formation from ozonolysis of α‐pinene

Semi‐empirical secondary organic aerosol (SOA) models typically assume a well‐mixed organic aerosol phase even in the presence of hydrophobic primary organic aerosols (POA). This assumption significantly enhances the modeled SOA yields as additional organic mass is made available to absorb greater amounts of oxidized secondary organic gases than otherwise. We investigate the applicability of this critical assumption by measuring SOA yields from ozonolysis of α‐pinene (a major biogenic SOA precursor) in a smog chamber in the absence and in the presence of dioctyl phthalate (DOP) and lubricating oil seed aerosol. These particles serve as surrogates for urban hydrophobic POA. The results show that these POA did not enhance the SOA yields. If these results are found to apply to other biogenic SOA precursors, then the semi‐empirical models used in many global models would predict significantly less biogenic SOA mass and display reduced sensitivity to anthropogenic POA emissions than previously thought.

S-Benzylthiuronium PVC matrix membrane sensor for potentiometric determination of cationic surfactants in some pharmaceutical formulation

The construction and characteristic performance of s-benzylthiuronium ( s-BT)–PVC membrane sensor responsive for cetylpyridinium chloride (CPC) are described. The sensor is based on the use of s-BT–tetraphenylborate (TPB) ion pair as electroactive material in PVC matrix in presence of dioctylphthalate as solvent mediator. The membrane sensor shows a fast, stable and near Nernstian response for CPC over the concentration range of 6 × 10 −6–1 × 10 −3 M at 25 °C and pH range 6–12 with cationic slope of 57.0 ± 0.4. The lower detection limit is 4 × 0 −6 M and the response time is 10–30 s. Selectivity coefficients for CPC relative to a number of different species were investigated, which there is negligible intereferences are caused by most of investigated cations, anions, and some organic compounds. The determination of 2.0–350.0 μg/ml of CPC in aqueous solutions shows an average recovery of 98.8%and a mean relative standard deviation of 1.87% at 64.0 μg/ml. The determination of CPC in mouthwash pharmaceutical solution gave results that compare favorably with those obtained by the British pharmacopoeia method. The s-benzylthiuronium electrode has been utilized as an end point indicator electrode for some precipitation titration reactions involving CPC as titrant.

PVC matrix membrane sensor for potentiometric determination of metoclopramide hydrochloride in some pharmaceutical formulations

The construction and characteristic performance of metoclopramide (MCP)–polyvinyl chloride (PVC) membrane sensor are described. The sensor is based on the use of MCP–tetraiodomercurate ion pair as electroactive material in PVC matrix in presence of dioctylphthalate (DOP) as solvent mediator. MCP membrane sensor shows a stable, near Nernstian response over the concentration range 1×10 −2–6×10 −5 M of MCP at 25 °C in the pH range 3–7 with cationic slope of 53.0±0.5. The detection limit of 4×10 −5 M and the response time of 30–60 s have been attained. Selectivity coefficient data for some common ions show negligible intereferences. Direct potentiometric determination of 15–3540 μg/ml MCP show an average recovery of 98.5% and a mean relative standard deviation (R.S.D.) of 1.6% at 100.0 μg/ml. The determination of MCP in Primperan tablets, injection, and syrup gave results that compare favorably with those obtained by the British pharmacopoeia method. Precipitation titrations involving MCP as titrant are monitored with the MCP sensor for some potentiometric precipitation reaction, e.g. sodium tetraphenylborate (STPB) and phosphomolybdic acid (PMA).