PVC Solution Research Articles

Tunable focus poly(vinyl chloride) gel microlens Array fabricated by shaping in patterned electric field

AbstractIn this work, we demonstrate a poly(vinyl chloride) (PVC)‐gel‐based microlens array (MLA) with tunable focus. The MLA is fabricated using a PVC solution and a glass substrate with a ring‐array‐patterned electrode. By coating the solution on the substrate and applying a direct current (DC) voltage to the electrode, a PVC gel membrane with a convex surface profile on the inner region of the electrode (anode) is formed with the solvent evaporation. After the complete evaporation of the solvent and removing the voltage, the solidified PVC gel membrane exhibits an MLA character. When an inverse DC voltage is applied to the electrode, the PVC gel accumulated on the inner region will shift toward the outer electrode connected to the anode, leading the curvature of the convex surface to decrease and the focal length to increase accordingly. The variable surface profile with voltage is precisely measured by a laser confocal microscope and the result shows that the focal length of the MLA can be tuned within a large range.

Graphene Modification by Curcuminoids as an Effective Method to Improve the Dispersion and Stability of PVC/Graphene Nanocomposites.

A large amount of graphene-related research is its use as a filler for polymer composites, including thin nanocomposite films. However, its use is limited by the need for large-scale methods to obtain high-quality filler, as well as its poor dispersion in the polymer matrix. This work presents polymer thin-film composites based on poly(vinyl chloride) (PVC) and graphene, whose surfaces were modified by curcuminoids. TGA, UV-vis, Raman spectroscopy, XPS, TEM, and SEM methods have confirmed the effectiveness of the graphene modification due to π-π interactions. The dispersion of graphene in the PVC solution was investigated by the turbidimetric method. SEM, AFM, and Raman spectroscopy methods evaluated the thin-film composite's structure. The research showed significant improvements in terms of graphene's dispersion (in solutions and PVC composites) following the application of curcuminoids. The best results were obtained for materials modified with compounds obtained from the extraction of the rhizome of Curcuma longa L. Modification of the graphene's surface with these compounds also increased the thermal and chemical stability of PVC/graphene nanocomposites.

Effect on the conductivity of ZnO nanoparticle dopped in PVC films

ZnO Nanoparticle was doped on PVC solution at different concentrations and made films with different thicknesses. The conductivity is measured for different applied fields and temperatures for ZnO nanoparticle doped and undoped films. The plot of ln σ versus 1/T × 10−3 K shows the nonlinear nature. From the plot, it is found that the conductivity increases more sharply for the doped sample than the undoped sample within the intermediate range of temperature. The activation energy is calculated for different regions from the plot and found to increase with the increase of doping.

Dechlorination of landfill poly(vinyl chloride) waste and estimation of recovered chlorine

The wet treatment process was used for the dechlorination of poly(vinyl chloride) (PVC) landfill waste plastic, and the process has shown dependence on concentration of alkali. The process of dechlorination of PVC has shown dependence on the concentration of the alkaline solution and the type of organic solvent used in the preparation of the alkaline solution. Ethylene glycol (EG), diethylene glycol (DEG), and tetraethylene glycol (TEG) are the diols that have been investigated. Moreover, the temperature of the PVC dechlorination process and the time of the PVC solution reflux showed effects on the final degree of the dechlorination (DD%). These were calculated using the Mohr method, where the chloride ions were titrated with a standard solution of silver nitrate in the presence of chromate ions. The study shows that 1 M NaOH/TEG alkaline solution was the best to dechlorinate PVC waste with the wet treatment process at 160 ̊c and for 3 h reflux and the process reclaimed poly(vinyl alcohol) PVA as the main product according to the hydroxyl group substitution mechanism (SN2), besides a few units according to the hydrogen chloride elimination mechanism (E2) with a few remaining chlorinated chains after analysis.

Manufacturing homogenous PVC/graphene nanocomposites using a novel dispersion agent

The goal of the study was to prepare a graphene (GN) dispersion in a poly (vinyl chloride) (PVC) solution with enhanced stability of the nanofiller thanks to the application of curcuma extract (CE). The stable dispersion was used to obtain PVC/GN nanocomposites with more homogeneous graphene by the solvent evaporation method. The CE effectiveness was compared with two commercially available dispersants in the form of oleic acid (OA) and polysorbate 80 (P80).The chemical composition of the CE was examined by Fourier-transform infrared spectroscopy. The dispersion stability was tested by the multiple light scattering method (Turbiscan Lab) and evaluated visually over a period of 40 days. The homogeneity of the filler's dispersion in the PVC matrix was evaluated by scanning electron microscopy and Raman spectroscopy.The application of the dispersing agents led to improved stability of the graphene dispersion in PVC solution. CE was the agent that most effectively improved the homogeneity of graphene dispersion, both in dispersions in a PVC solution and in PVC/GN nanocomposite films.

Effect of Temperature and Concentration on the Optical Properties of PVC Solutions

Effect of Temperature and Concentration on the Optical Properties of PVC Solutions

A simple route to PVC encapsulated Na2SO4·10H2O nano/micro-composite with excellent energy storage performance

A novel Na2SO4·10H2O micro/nanostructure (encap-Na2SO4·10H2O/PVC) encapsulated in poly(vinyl chloride) (PVC) is fabricated via mixing water-dispersible Na2SO4·10H2O micro/nanocrystals with a PVC solution at low temperature. Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) confirm the encapsulation of the Na2SO4·10H2O in the PVC matrix. Thermal analysis showed encap-Na2SO4·10H2O/PVC core-shell structures possess a high latent heat (194.6 J/g) and high stability, and the larger Na2SO4·10H2O cores with thicker PVC shells should improve the heat storage stability of the material. More importantly, the simple, low temperature, and environmentally conscious way for preparing encap-Na2SO4·10H2O/PVC composites may be extended to other promising phase change materials (PCMs).

The Role of Chitosan on Polyvinyl Chloride (PVC)-Glycerol Biocomposites for Blood Bag Application

The common blood bag in the market is made from a mixture of PVC and plasticizer. But the a number of occurrences where pockets of heavily polluted bacteria, blood requires blood bags which has the antibacterial characteristic. Antibacterial properties on the bags of blood can be raised with the addition of chitosan. This research aim is to know the influence of chitosan membrane biocomposite PVC-Glycerol against its biological and physical properties. Chitosan dissolved with a concentration of 0 wt/v%; wt/v 0.5%; 1 wt/v%; 1.5 v/wt% wt/v and 2 wt/v% mixed with glycerol with a 1:1 ratio. Then the mixture was mixed with PVC solution 15% and formed into a membrane by using the glass plates. Furthermore, the membranes are characterized using tensile test, hemolytic test, and antibacterial test. The physical characteristics of the tensile test indicate that the elongation percentage was 2.22 – 96.43% and tensile strength was 3.6-8 MPa. The test result of the hemolytic test and antibacterial test showed that biocomposite membrane of PVC-Glycerol-Chitosan are hemocompatible because it has a hemolysis percentage < 5%, while antibacterial test results showed that the membrane has a weak anti-bacterial due to bacterial inhibition zone diameter < 5 mm. Based on the characterization result, biocomposite membrane of PVC-Glycerol-Chitosan can be used for blood bag candidate.

Modification of poly(vinyl chloride) films by aliphatic amines to prepare anion-exchange membranes for Cr (VI) removal

ABSTRACTA method for the synthesis of anion-exchange membranes by the grafting of ethylenediamine (EDA), diethylenetriamine (DETA) or pentaethylenehexamine (PEHA) onto poly(vinyl chloride) (PVC) film has been presented. The chemical structure was determined by means of Fourier Transform Infrared Spectroscopy (FTIR) and the membranes were characterized by ion-exchange capacity, chloride and nitrogen contents, water regain and surface energetics. The obtained membranes were evaluated in the Donnan dialysis (DD) of hexavalent chromium solutions. Among the membranes, those modified with EDA and DETA showed the best separation features: high flux and high recovery factor (RF). The highest degree of recovery was observed for membranes prepared by the casting of PVC solution in (THF), followed by grafting EDA.

Reproducible Superhydrophobic PVC Coatings; Investigating the Use of Plasticizers for Early Stage Biofouling Control

Here we show an easy to synthesize superhydrophobic material using a solvent phase–separation process of poly vinyl chloride. It is found that solvents mixed in different ratios increase the dielectric value of the solvent and can be tuned to produce superhydrophobic PVC. The PVC solution is then spin‐coated onto glass slides for characterization using scanning electron microscopy. Plasticizers are doped into the 70% (v/v) PVC to determine their overall effects; it is found that plasticizers reduce the water contact angle value. The final coatings were tested in a series of antifouling assays in a marine environment lab study; it is found that the superhydrophobic PVC material reduced marine biofouling.

Properties of Composite Films from Sugarcane Bagasse, Coconut Coir, and Water Hyacinth Fibers/Poly(Vinyl Chloride)

Composite films from sugarcane bagasse fibers (SBF), coconut coir fibers (CCF) and water hyacinth fibers (WHF)/poly (vinyl chloride) (PVC) were successfully fabricated by solvent-casting technique. Fibers were treated with sodium hydroxide alkali solution and followed by vinyltriethoxysilane solution. Both untreated fibers (USBF, UCCF, and UWHF) and treated fibers (TSBF, TCCF, and TWHF) were incorporated into PVC solutions at concentrations of 5-15% w/w based on total solid weight. The average diameters of TSBF, TCCF, and TWHF were 145±17 μm, 164±15 μm, and 128±12 μm, respectively. Tensile strengths of PVC/treated fibers were higher than those of PVC/untreated fibers. Tensile strength, tensile modulus, and elongation at break of composite films were lower than those of neat PVC films. In case of PVC/TSBF and PVC/TCCF, tensile strength and modulus were decreased, whereas, these properties of PVC/TWHF were increased with increasing amount of fibers. Among these composite films, PVC/15TWHF had the highest tensile strength and modulus which were 7.1±0.2 and 350±27 MPa, respectively. Composite films of PVC/15TSBF, PVC/15TCCF, and PVC/15TWHF were thermally stable than the neat PVC film. The amounts of water absorption of composite films were increased with time and with increasing amount of fibers. The results showed the potential for using PVC/natural fiber composite films in packaging application in which the tensile strength and tensile modulus were comparable to that of conventional film such as low density polyethylene (LDPE).

Modified zeolitic imidazolate framework-8 as solid-phase microextraction Arrow coating for sampling of amines in wastewater and food samples followed by gas chromatography-mass spectrometry

In this study, a novel solid phase microextration (SPME) Arrow was prepared for the sampling of volatile low molecular weight alkylamines (trimethylamine (TMA) and triethylamine (TEA)) in wastewater, salmon and mushroom samples before gas chromatographic separation with mass spectrometer as detector. Acidified zeolitic imidazolate framework-8 (A-ZIF-8) was utilized as adsorbent and poly(vinyl chloride) (PVC) as the adhesive. The custom SPME Arrow was fabricated via a physical adhesion: (1) ZIF-8 particles were suspended in a mixture of tetrahydrofuran (THF) and PVC to form a homogeneous suspension, (2) a non-coated stainless steel SPME Arrow was dipped in the ZIF-8/PVC suspension for several times to obtain a uniform and thick coating, (3) the pore size of ZIF-8 was modified by headspace exposure to hydrochloric acid in order to increase the extraction efficiency for amines. The effect of ZIF-8 concentration in PVC solution, dipping cycles and aging temperature on extraction efficiency was investigated. In addition, sampling parameters such as NaCl concentration, sample volume, extraction time, potassium hydroxide concentration, desorption temperature and desorption time were optimized. The Arrow-to-Arrow reproducibilities (RSDs) for five ZIF-8 coated Arrows were 15.6% and 13.3% for TMA and TEA, respectively. The extraction with A-ZIF-8/PVC Arrow was highly reproducible for at least 130 cycles without noticeable decrease of performance (RSD<12.5%). Headspace SPME of 7.5mL sample solution with the fabricated ZIF-8 coated Arrow achieved linear ranges of 1–200ngmL−1 for both TMA and TEA. The limit of quantitation (LOQ) was 1ngmL−1 for both TMA and TEA. The method was successfully applied to the determination of TMA and TEA in wastewater, salmon and mushroom samples giving satisfactory selectivity towards the studied amines.

USING OF AGRICULTURAL DRAINAGE WATER FOR LETTUCE PRODUCTION IN HYDROPONIC SYSTEM

The objectives of the present work were to study the effects of irrigation with Agricultural Drainage Water (ADW) on lettuce (Lactuca sativa L.) yield, quality, and water use efficiency (WUE) with hydroponic system. Five mixing treatments of Agricultural drainage water (ADW) with fresh water (mean normal irrigation water) were used T1:(100% agricultural drainage water), T2:(75% agricultural drainage water mixed with 25% fresh water), T3:(50% agricultural drainage water mixed with 50% fresh water), T4:(25% agricultural drainage water mixed with 75% fresh water), and T5:( 100% fresh water). Nutrient Film Technique (NFT) hydroponic system was developed with five pipes PVC and nutrient solution added in rates: 12.5%, 25%, 50%, 75%, and 100% from standard nutrient solution for T1, T2, T3, T4, and T5, respectively. The results showed that lettuce plant can be produced in 50 days from planting to harvest by (NFT) hydroponic system. Moreover irrigation by using T3 had effectively increased the yields of green and dry matter. The higher Lettuce yields obtained with trend T3 > T5 > T2 > T4 > T1. And plants irrigated with T3 used water more efficiently than those irrigated with other water treatments. The higher water use efficiency (WUE) 39.96 kg/m3 was obtained with T3 and the lower value 16.67 with T1. On the other hand mineral nutrient contents in dry matter of N, P, K, and Ca contents were obviously higher in plants irrigated with T5 than with other water treatments. Heavy metals (Cd, Ni, Cr and Pb) contents in Lettuce shoots were higher in plants irrigated with T3 than those irrigated with other water treatments, but their levels did not reached the maximum allowed levels by FAO for edible crops.

Evaluation of glass transition temperature of PVC/POSS nanocomposites

Abstract The poly(vinyl chloride) was modified by polyhedral oligomeric silsesquioxane with 3-chloropropyl groups (CP–POSS) by POSS concentration between 0.5 and 5 wt%. Two methods of POSS incorporation were applied, i.e. direct solid powders mixing or addition of POSS to PVC solution in THF. The final samples were produced by melt mixing in the Brabender mixer chamber. By means of the glass transition temperature (T g ) determination the influence of a low contain of CP–POSS on the effect of plasticization of the PVC compounds was investigated. Depending on the measurements method (dynamic mechanical analysis DMA and differential scanning calorimetry DSC) and on the DMA measurement frequency various values of the T g were observed. It was found that CP–POSS may act as a plasticizer, leading to certain lowering of the glass transition temperature of poly(vinyl chloride).

Electrospun Conditions of Poly(vinyl chloride) Nanofibrous Membrane Plasticized with Polyurethane

Electrospun poly(vinyl chloride) (PVC) nanofibrous were prepared by electrospinning. Various concentration of polyurethane (PU) were added to PVC solution for plasticization of the electrospun nanofibrous. The pristine and plasticized nanofibrous were characterized by field emission scanning electron microscopy (FE-SEM), differencial thermal analysis (DTA), and thermogravimetry analysis (TGA), respectively. Thermal properties form DTA and TGA results indicated that the addition of PU decreased glass transition temperature (Tg) of PVC and increased heat resistance of PVC nanofiber. The dielectric constant of plasticized nanofibrous measured using precision LCR meter indicated that the membrane were dense.

Electrospun Epoxidized Natural Rubber with Poly(vinyl chloride) (ENR-PVC) Nanofibrous for PEMFC Applications

Various electrospun epoxized natural rubber / poly (vinyl chloride) (ENR/PVC) blend nonwoven membranes were prepared by electrospinning technique. Various concentration of epoxidized natural rubber (ENR) solution in N,N-dimethylformamide (DMF) were directly added to PVC solution for plasticization of the electrospun nanofibrous. Differencial thermal analysis (DTA), thermogravimetry analysis (TGA), fourier transfrom infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) were used to characterize the pristine and plasticized nanofibrous. DTA results indicated that the addition of ENR resulted in the shifting of glass transition temperature (Tg) towards lower temperatures. The blending of PVC with ENR is thermodynamically incompatible.

Effect of Inorganic Silver Nanoparticles on Structural and Electrical Properties of Polyaniline/PVC Blends

Dodecylbenzenesulfonic acid (DBSA) doped polyaniline (PANDR) has been synthesized by redoping method. Inorganic silver nanoparticles were incorporated in THF solution of PANDR (PANDS) and then mixed with PVC solution to prepare PANDS/PVC nanocomposites. FTIR spectroscopy indicated that silver nanoparticles reside more close to imine nitrogen of PANDS. Transmission electron microscopy (TEM) confirmed the formation and dispersion of silver nanoparticles in polymer matrix having average size of ~20 nm. Incorporation of inorganic metal silver nanoparticles has improved the mechanical properties of nanocomposite films as compared to pure polymer blends. Addition of silver nanoparticles in the blends reduces the charge trapping centres and increases the conducting channels; as a result a decrease in the real part of impedance has been observed.

Optimization of a new polymeric chromium (III) membrane electrode based on methyl violet by using experimental design

Plackett-Burman and Box-Behnken designs were applied as experimental design strategies to screen and optimize the influence of membrane ingredients on the electrode performance. A new poly(vinyl chloride) membrane sensor for Cr(III) based on methyl violet as an ionophore was planned. The major variables to find a model for achieving the best Nernstian slope as response were: PVC, plasticizers, methyl violet, KpClTPB, pH, conditioning time and internal solution concentration. Plackett-Burman design was used to screen the main factors and Box-Behnken response surface was led to find a model for optimizing the response. The optimized membrane electrode shows a Nernstian slope for chromium (III) ions over a wide linear range from 1.99x10(-6) to 3.16x10(-2)molL(-1) and a slope of 19.5+/-0.1mVdecade(-1) of activity. It would be successfully applied in the pH range from 3.5 to 6.5 with detection limit of 1.77x10(-6)molL(-1) (0.092mgL(-1)). The response time of the sensor is about 8s and the membrane can be used for more than 6 weeks without any deviation. The relative standard deviations (R.S.D.) for six replicate the measurements of 1.0x10(-4) and 1.0x10(-3)molL(-1) of Cr(III) were 3.2 and 3%, respectively. The electrode revealed comparatively good selectivity with respect to many cations including alkali earth, transition and heavy metal ions. The electrode was successfully used as an indicator in the potentiometric titration of Cr(III) with EDTA and was also applied to the direct determination chromium (III) content of spiked water and soil samples.

Characterization of suspension poly(vinyl chloride) resins and narrow polystyrene standards by size exclusion chromatography with multiple detectors: Online right angle laser-light scattering and differential viscometric detectors

This work reports the utilization of a multi-detector size chromatography for the characterization of poly(vinyl chloride) (PVC) resins prepared by suspension polymerization in the range of temperatures between 21 and 75 °C. The chromatography equipment offers the possibility of analyzing the samples in terms of their absolute molecular mass using a combination of three detectors (TriSEC): right angle light scattering (RALLS), a differential viscometer (DV) and refractive index (RI). The PVC resins were fully characterized concerning the molecular weight distribution (MWD), its dependence with intrinsic viscosity ( η) and molecular sizes (radius of gyration, R g and hydrodynamic radius, R h). Additionally, it is also presented the characterization of polystyrene narrow standards serving as reference polymers. It is possible to find in the literature several methodologies concerning the breaking of typical aggregates presented in PVC solutions. The most suitable for the experiments were chosen, adapted and analysed by light scattering. It was observed that the application of the TriSEC to study PVC solutions was effective and it was concluded that this is an important tool for the polymer characterization, opening the possibility of running experiments avoiding the need of fractionation of the polydisperse PVC in order to obtain the Mark–Houwink–Sakurada (MHS) constants, or the utilization of MHS, that are quite diverse in literature.

Amperometry of Heparin Polyion Using a Rotating Disk Electrode Coated with a Plasticized PVC Membrane

Electrochemical method of detection of heparin polyion was developed based on voltammetry of heparin on a rotating glassy carbon (GC) electrode coated with a plasticized PVC membrane. The membrane was deposited on the GC disk by spin-coating technique using a mixture of solutions of PVC in tetrahydrofuran, and 1,1′-dimethylferrocene (DMFc) and hexadecyltrimethylammonium tetrakis(4-chlorophenyl)borate (HTMATPBCl) in o-nitrophenyl octyl ether. UV/vis reflection spectrometry was used to evaluate the membrane thickness, which exhibits a linear correlation with the membrane resistance measured by impedance spectroscopy. It is shown that this electrode can be used for amperometric or coulometric detection of heparin in aqueous samples of medically relevant concentrations (1–10 U mL−1), with a detection limit of 1.4 U mL−1. Evidence is provided indicating that the current determining step is the reversible adsorption of the ion-pair of heparin polyion with HTMA+ cation at the membrane/aqueous electrolyte interface, which is driven by oxidation of DMFc at the GC/membrane interface.