PVC Matrix Research Articles

Structure and properties of poly(vinyl chloride)/graphene nanocomposites

The goal of the paper was to investigate the influence of graphene (GN) on properties and structure of suspensive poly(vinyl chloride) (PVC). PVC/GN nanocomposites were obtained by the solvent evaporation method, and their structures were evaluated using optical microscopy, SEM, FT-IR, XRD and Raman spectroscopy methods. Thermal properties of the obtained materials were studied by TGA. Electrical properties and swelling behaviour were also determined.The microscopic observations confirm a uniform distribution of graphene in the PVC matrix. The investigations carried out indicated an effect of graphene on a decrease in resistivity to a value which enabled to include the PVC/GN nanocomposites into anti-static materials group. On the basis of swelling studies, it has been found that the PVC/GN nanocomposites have a higher chemical resistance against acetone while compared to pure poly(vinyl chloride). The properties of the obtained materials depend significantly on content and dispersion level of graphene in the PVC matrix. An impact of GN on the acceleration of the PVC degradation process was found.

Suitable materials selection that act as a retardant agent against microwave radiation and electronics packaging to human life

Recently there is a high attempts to investigate the possibility of protecting human body from microwave radiation and electronics packaging. In this study an electromagnetic radiation shielding film by reflecting and/or absorbing the incident wave were prepared as a promising solution. Basically PVC and iron oxide nanoparticles were synthesized using solution casting method to make the protection film. Analysis via VNA has been conducted to understand the shielding behaviour during the exposure to the radiation. The prepared films exhibit ability of absorbing microwave radiation in the range of 8 GHz – 11 GHz, with a maximum value of -10 dB at 30 wt. % of iron oxide nanoparticle. Furthermore microwave absorption performance can be improved by putting two layers or more in order to increase the thickness of the shield. It is suggested that the results are mainly attributable to good effective properties of iron oxide and their homogeneous dispersion in the PVC matrix, also from the analysis it will propose the optimum solutions for this problem.

Using Methacryl-Polyhedral Oligomeric Silsesquioxane as the Thermal Stabilizer and Plasticizer in Poly(vinyl chloride) Nanocomposites.

In this study, we investigated the influence of methacryl-functionalized polyhedral oligomeric silsesquioxane (MA-POSS) nanoparticles as a plasticizer and thermal stabilizer for a poly(vinyl chloride) (PVC) homopolymer and for a poly(vinyl chloride)/dissononyl cyclohexane-1,2-dicarboxylate (PVC/DINCH) binary blend system. The PVC and the PVC/DINCH blend both became flexible, with decreases in their glass transition temperatures and increases in their thermal decomposition temperatures, upon an increase in MA-POSS content, the result of hydrogen bonding between the C=O groups of MA-POSS and the H–CCl units of the PVC, as determined using infrared spectroscopy. Furthermore, the first thermal decomposition temperature of the pure PVC, due to the emission of HCl, increased from 290 to 306 °C, that is, the MA-POSS nanoparticles had a retarding effect on the decomposition of the PVC matrix. In tensile tests, all the PVC/DINCH/MA-POSS ternary blends were transparent and displayed flexibility, but their modulus and tensile strength both decreased, while their elongation properties increased, upon an increase in MA-POSS concentration, both before and after thermal annealing. In contrast, the elongation decreased, but the modulus and tensile strength increased, after thermal annealing at 100 °C for 7 days.

Thermal and wear behavior of three inorganic fiber-reinforced wood-plastic composites in simulated soil aging conditions

This study investigated the effects of simulated soil aging on the thermal and wear properties of rice husk fiber/polyvinyl chloride (PVC) composites reinforced with three inorganic fibers (aluminum silicate fiber (AS); basalt fiber (BF) and zirconia fiber (ZF)). The thermal and wear behavior of the composites exhibited a downward trend during the simulated soil aging process; weak interface (pulling out of fiber) resulted in the induction of strength and anti-aging properties. However, the addition of inorganic fibers improved the anti-aging properties of the composites. When the simulated soil aging time was up to 21 d, ZF reinforced composites (ZFRC) exhibited high thermal and wear resistance properties due to superior interfacial adhesion between the fiber and PVC matrix. The average friction coefficient (μ) and specific wear rate (K) of ZFRC were reduced by 12.1% and 40.7%, respectively, compared to the unreinforced composites.

Bismuth oxychloride nanosheets for improvement of flexible poly (vinyl chloride) flame retardancy

Bismuth oxychloride nanosheet modified with silane coupling agent (KH570-BiOCl) was prepared by a facile liquid-phase method and used as a green inorganic flame retardant to replace Sb2O3, a conventional flame retardant of flexible poly (vinyl chloride), PVC in short. The as-prepared nanosheet was characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectrometry. Its effect on the flame-retardant performance of PVC was investigated by cone calorimetry test (CCT) in association with thermogravimetric analysis (TGA) as well as condensed-phase and gas-phase analyses by Raman spectroscopy and thermogravimetric–infrared spectrometry, respectively. TGA and CCT results indicated that, as a potential flame retardant of PVC, the as-prepared KH570-BiOCl nanosheet with a thickness of about 30–40 nm had good charring ability and could effectively improve the flame retardancy of PVC. Particularly, the PVC-matrix composite with 3% (mass fraction) of KH570-BiOCl nanosheet exhibited 18.65% of char residue as well as significantly reduced the peak heat release rate (45.3%), peak smoke production rate (55.3%) and total smoke production (31.4%). This is because the BiOCl nanosheet could act as a physical barrier to prevent the heat transfer as well as the release and diffusion of the decomposed products of PVC matrix, while it also could catalyze and promote the formation of char layer in the manner similar to that of gaseous phase of Sb2O3. Thus, the KH570-BiOCl nanosheet showed great potential to replace Sb2O3 and provided the promising manner to develop an environmental friendly PVC composite.

Effects of nano-clay content, foaming temperature and foaming time on density and cell size of PVC matrix foam by presented Least Absolute Shrinkage and Selection Operator statistical regression via suitable experiments as a function of MMT content

Present article aims to investigate the effect of nano-clay content, foaming temperature and foaming time on the density and cell size of the PVC matrix foam. The cell size would affect the insulating and mechanical properties. The foaming temperature is set in three levels of 70, 80 and 90 °C, foaming time is set in three levels of 10, 20, and 30 s; and nano-clay is in content of 1, 3, and 5 wt%. Outputs consist the density and cell size, which affect impact the thermal conductivity, mechanical properties and the weight of the polymer foam. In addition the Least Absolute Shrinkage and Selection Operator (LASSO) regression method is employed in order to improve both the precision and generalization of the estimated foam density and cell size as functions of the MMT content, the foaming temperature and the foaming time. LASSO is found a suitable approach to predict the sample properties.

Solid-state polymer membranes for simple, sensitive, and low-cost monitoring of mercury in water

Solid-state Hg(II) selective membranes were produced and assessed by means of X-ray absorption near edge structure in the total reflection X-ray fluorescence (TXRF-XANES) setup and by the energy dispersive X-ray fluorescence (EDXRF) technique. Membranes were functionalized using four promising ligands for mercury complexation, i.e.: i) 4-(2-Pyridylazo) resorcinol (PAR), ii) thiourea, iii) calconcarboxylic acid (CCS), and iv) dithizone. A simple analytical procedure was followed, using miniscule reagent quantities, thus suggesting the process is also cost-effective. TXRF-XANES revealed that mercury complexes with the ligands, and is not simply adsorbed onto the PVC matrix, while the complexation was found to not be affected by the matrix existence. Mercury exhibited an increased oxidation grade and was covalently bound to the ligand functional groups, via a strong chemical bond. EDXRF revealed that the solid-state membranes can be used for mercury speciation and trace analysis from environmentally relevant matrices, such as tap water. The membranes could be a promising alternative to polymer inclusion membranes (PIMs), due to their simple configuration and high Hg (II) selectivity in aqueous media, but more research is needed. PAR appears to be the most promising ligand, followed by dithizone and thiourea. CCS had a minuscule preconcentration efficiency since it was preferably bound with Cu in tap water, indicating limited usefulness for mercury preconcentration. However, results suggest that, depending on the ligand, the solid-state membranes could be also possibly used for multi-elemental heavy metals analysis in water.

Calcium Iron Layered Double Hydroxide/Poly(vinyl chloride) Nanocomposites: Synthesis, Characterization and Cd2+ Removal Behavior

Poly(vinyl chloride) (PVC) and other thermoplastics have received more attention in the last decades due to their high fire resistance, hydrophobicity, and flexibility. To improve the thermal stability of these classes of polymers, heat stabilizers should be used. Layered double hydroxides (LDHs) are a green and inexpensive class of heat stabilizers. In this study at first, the co-precipitation method was used to prepare nanostructure calcium/iron layered double hydroxide (Ca/Fe-LDH), and then it was organo-modified with citrate as a green and environmentally friendly anion. In the next step, it was used as a nanofiller for improving the thermal properties of the PVC matrix. Accordingly, LDH-Cit/PVC nanocomposites (NCs) with different amounts of LDH-Cit (5, 10 and 15 wt%) were synthesis by ultrasonic irradiation technique. The structural, morphological, and thermal properties of the synthesized NCs were evaluated with XRD, FT-IR, FE-SEM, TGA techniques. By introducing of LDH-Cit in the NCs, the residue at 800 °C was increased from 10 to 23% compared to pure PVC. The NCs ability to removing Cd2+ metal ion and the effects of time, pH, and Cd2+ concentration on the removal efficiency of Cd2+ were studied. Due to the increase of the adsorbent mass and removal efficiency of Cd2+, the 60 mg L−1 of Cd2+ concentration and pH of 7 were chosen as the optimized condition. Also, kinetics studies on the experimental data for adsorbents showed acceptable adaptation with the Langmuir isotherm and pseudo-second-order kinetic model.

Evaluating the Effect of four Hosting Ionophores on the Performance of Anion Selective Potentiometric Sensor

AbstractA systematically designed practical approach was carried out for the optimization of an anion selective electrode for the determination of an anionic laxative, docusate sodium (DS). The PVC membrane composition and the sensor assembly were systematically optimized. Different sensors were fabricated using tetradodecylammonium bromide (TDAB), tridodecylmethylammonium bromide, tetraheptylammonium bromide as ion exchangers. The effect of ionophore was evaluated using four different host‐guest ionophores, namely; calix[8]arene, β‐cylodextrin, hydroxypropyl‐β‐cylodextrin and carboxymethyl‐β‐cylodextrin to reach the optimum membrane composition. Sensors were constructed in both liquid membrane and solid contact sensor‐assemblies. The slope, linear range, LOQ and response time for each sensor was calculated to assess their performance characteristics. Best Nernstian slope of −61.38 mV/decade and lowest quantification limit of 7.62×10−7 M was achieved by the sensor containing TDAB as ion exchanger and Calix[8]arene as ionophore in the PVC matrix using the gold wire solid contact sensor assembly. Electrode selectivity was assured in the presence of DS potential degradation product, common interfering ions and industrial excipients of tablet and gel formulations. Validation was carried out regarding the ICH validation parameters.

Design and Study of Electrochemical Sensors Based on Polymer Inclusion Membranes Containing Polyoxometalates

Polyoxometalates (POM) are a class of inorganic compounds with various structures and remarkable electrical, magnetic and optical properties. Ion-pair complexes formed with some organic cations have high lipophilicity and they can be used as ionophores for PVC matrix membranes with active recognition function. The present study describes the construction and characterization of selective membrane sensors based on electroactive material incorporated in PVC matrix. They have been employed for the determination of ranitidine and nizatidine by using their complexes with silicotungstic acid as ionophores. The composition of the membrane has been optimized. The linear response range for both sensors was between 10-1-10-5M with quantification limits of 2.83�10-6M for ranitidine and 3.43�10-6M for nizatidine, and a response time shorter than 50 seconds. The new electrodes have been used for the potentiometrical determination of ranitidine and nizatidine in pharmaceutical products.

PREPARATION OF A NEW MOLECULARLY IMPRINTED POLYMERS AND ITS USE IN THE SELECTIVE EXTRACTION FOR DETERMINATION BROMHEXINE HYDROCHLORIDE AT PHARMACEUTICALS

This study was aimed four electrodes were synthesized based on molecularly imprinted polymers (MIPs). Two MIPs were prepared by using bromhexine hydrochloride (BHH) as the template, acryl amide (AA) and methyl methacrylate (MMA) as monomers as well as ethylene glycol dimethacrylate (EGDMA) and penta erythritol triacrylate (PETA) as cross linkers respectively and benzoyl peroxide as initiator. The same composition was used in preparation of non-imprinted polymers (NIPs), but without the template (Bromhexine hydrochloride). To prepare the membranes, different plasticizers were used in PVC matrix such as: Di butyl sebacate (DBS), acetophenone (AP), di-octyl phthalate (DOPH) and tri-2-ethyl hexyl phosphate (TEHP). The characteristics studied are the slop, detection limit, life time and linearity range of BHH–MIPs electrodes. Results obtained of selectivity measurements on interfering cations (Al+3, Ca+2, K+) and some pharmaceutical additives such as methylparaben, propylparaben, trisodium citrate show that no interfering with drug bromhexine hydrochloride. The preparation electrodes have been shown good response including testing pharmaceutical analysis.

Rigid antimicrobial polimeric composite with PVC matrix and ZnO and TiO2 functionalized nanoparticles

Rigid antimicrobial polimeric composite with PVC matrix and ZnO and TiO2 functionalized nanoparticles

Spectroscopic, optical and thermal characterization of polyvinyl chloride-based plasma-functionalized MWCNTs composite thin films

In this work, homogeneous PVC/MWCNT nano-composite films with different concentrations of MWCNTs were prepared. The MWCNTs were treated with plasma to improve their compatibility in the PVC matrix. The prepared films are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV–visible spectroscopy (UV–Vis.) and thermogravimetric analysis (TGA). The XRD, XPS, FTIR and Raman results suggest that the plasma-functionalized MWCNTs are well dispersed and interacted with the PVC. XPS results show that the stoichiometric contents of C and O groups relatively increased with the increasing percentage of MWCNTs in the nano-composite, meanwhile, Cl group decreased. The optical band gap $$E_{\mathrm{g}}$$ of PVC–MWCNTs decreases with the increasing MWCNTs percentage in the nano-composite. Increasing the percentage of MWCNTs in the PVC nano-composite improves thermal stability, dielectric constant and AC conductivity.

Retraction Note to: Preparation of Multilayers Zinc Hydroxystannate Microcapsules and its Application in Flame-Retardant PVC Composites

Although research on halogen free flame retardant has achieved great progress, its practical application is restricted due to high additive amount and low efficency. To solve this problem, multilayers microcapsule [melamine–formaldehyde resin (MF)/silicon dioxide (SiO2)/zinc hydroxystannate (ZHS)] was prepared through a two-step method. Moreover, when 16.40 wt% SiO2/ZHS microcapsules was mixed with poly(vinyl chloride) (PVC) matrix, the obtained PVC composites exhibited a high limited oxygen index (LOI) of 32.5%, showing its excellent flame retardancy. Furthermore, for the compatibility between MF/SiO2/ZHS microcapsules and PVC to be improved, MF was coated to SiO2/ZHS microcapsules by in situ polymerization. When 16.40 wt% MF/SiO2/ZHS microcapsules were mixed with PVC matrix, the obtained PVC composites exhibited a high LOI of 35.5%, showing its high flame retardancy. Therefore, this easily prepared multilayers microcapsule with sufficient flame retardancy in this work, it could have a potential for engineering applications.

Morphology, mechanical property, and processing thermal stability of PVC/La‐OMMTs nanocomposites prepared viain situintercalative polymerization

Poly(vinyl chloride) (PVC) nanocomposites were prepared via anin situintercalative suspension polymerization of vinyl chloride with four organic carboxylic acid salts (montmorillonite [MMT] units) containing thermally stable lanthanum ions. The effects of different lanthanum organic montmorillonites (La‐OMMTs) on the particle features and molecular weight were investigated. The transmission electron microscopy data indicated the formation of partially exfoliated or intercalated PVC/La‐OMMTs nanocomposites. The effect of different functional groups on the mechanical properties and processing thermal stability of PVC/La‐OMMT nanocomposites were investigated. Tensile testing and two‐roll mill processing results showed that La‐OMMTs could enhance the dynamic thermal stability and mechanical properties versus PVC pure resin and PVC/I.30P nanocomposites (composed of PVC and I.30P). This suggested that the double bond and amidogen group in La‐OMMTs could promote the dispersion of La‐OMMTs in the PVC matrix and also improve the adhesion between the La‐OMMTs and PVC matrix. The results have potential value in the industrial development of PVC/La‐OMMTs nanocomposites. J. VINYL ADDIT. TECHNOL., 26:97–108, 2020. © 2019 Society of Plastics Engineers

Novel Potentiometric 2,6-Dichlorophenolindo-phenolate (DCPIP) Membrane-Based Sensors: Assessment of Their Input in the Determination of Total Phenolics and Ascorbic Acid in Beverages

In this work, we demonstrated proof-of-concept for the use of ion-selective electrodes (ISEs) as a promising tool for the assessment of total antioxidant capacity (TAC). Novel membrane sensors for 2,6-dichlorophenolindophenolate (DCPIP) ions were prepared and characterized. The sensors membranes were based on the use of either CuII-neocuproin/2,6-dichlorophenolindo-phenolate ([Cu(Neocup)2][DCPIP]2) (sensor I), or methylene blue/2,6-dichlorophenolindophenolate (MB/DCPIP) (sensor II) ion association complexes in a plasticized PVC matrix. The sensors revealed significantly enhanced response towards DCPIP ions over the concentration range 5.13 × 10−5–1.0 × 10−2 and 5.15 × 10−5–1.0 × 10−2 M at pH 7 with detection limits of 6.3 and 9.2 µg/mL with near-Nernstian slope of −56.2 ± 1.7 and −51.6 ± 2 mV/decade for sensors I and II, respectively. The effects of plasticizers and various foreign common ions were also tested. The sensors showed enhanced selectivity towards DCPIP over many other phenolic and inorganic ions. Long life span, high potential stability, high reproducibility, and fast response were also observed. Method validation was also verified by measuring the detection limit, linearity range, accuracy, precision, repeatability and between-day-variability. The sensors were introduced for direct determination of TAC in fresh and canned juice samples collected from local markets. The obtained results agreed fairly well with the data obtained by the standard method.

Ion-Selective Electrode Based on Thiosemicarbazide Schiff Base As Ionophore for Pb (II) Ion Sensor

Schiff bases ligands of thiosemicarbazide have received attention because of their biological and electrochemical activity as ionophore. For the present work, Schiff base was synthesised with thiosemicarbazide and thiophene-2 aldehyde in ethanol solvent. Pb (II) ion-selective electrode has been developed by using synthesized Schiff base ligand as ionophore in PVC matrix. This ISE was tested with various parameters such as slope of potential curve, linear response, effect of pH, selectivity and respose time etc. The prposed sensor can be used over a wide concentration range (1.0 ×10–7 to 1.0 ×10–2 M) for lead(II) with a slope of 29.4 ± 0.1 mV decade–1. It has releatively fast reasponse time (<10 s) with high selectivity in presence of various foreign ions. This ISE showed best performance with a membrane composition of PVC: DOP: Ionophore: NaTPB as 33: 59: 3.4: 4.6 (w/w %). The detection limit of the electrode was approximately 4.0 × 10–8 M and the electrode works well in the pH range of 2.4–8.0. The proposed electrode has found application as an indicator electrode for potentiometric titration of Pb(II) with EDTA. It can also be employed for the determination of Pb(II) ions in various wastewater samples. Figure 1

Study of the phase morphology and toughness in poly (vinyl chloride)/acrylonitrile–styrene‐acrylic/styrene–butadiene–styrene ternary blends influenced by interfacial/surface tension

ABSTRACTThe effect of interfacial interaction on the phase morphology and toughness of poly (vinyl chloride) (PVC)/acrylonitrile–styrene‐acrylic (ASA) terpolymer/styrene–butadiene–styrene (SBS) block copolymer ternary blends has been investigated. Water and diiodomethane liquids were used for static contact angle measurements to get surface tension and calculate interfacial tension. A dispersed phase morphology of ASA and SBS in the PVC matrix was predicted by the spreading coefficient theory, which was calculated through interfacial tensions between different polymer pairs. Extraction experiment and scanning electron microscopy were combined to verify this morphology. When the volume fraction of SBS was small, SBS was dispersed in the matrix as droplets and the strong PVC/styrene–acrylonitrile interfacial interaction made up for the poor interfacial adhesion between SBS and PVC. Herein, SBS showed an effective toughening effect on PVC/ASA blends. With the addition of 2.5‐ and 5‐phr SBS, the blends had the highest impact strength of 88.75 kJ/m2 at 23 °C and 9.98 kJ/m2 at 0 °C, respectively. With the further increase of the SBS content, the diameter of the SBS drops increased largely and the poor interfacial adhesion between SBS and PVC played a leading role, resulting in a sharp decrease in toughness and a sharp ductile–brittle transition. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47721.

Effect of temperature on the impact behavior of PVC/ASA binary blends with various ASA terpolymer contents

Abstract Acrylonitrile-styrene-acrylic (ASA) terpolymer has a typical core-shell structure with poly(butyl acrylate) (PBA) as the soft core and styrene-acrylonitrile (SAN) copolymer as the hard shell. The impact behavior of poly(vinyl chloride) (PVC)/ASA binary blends with various ASA terpolymer contents was systematically investigated at three different temperatures (23°C, 0°C, and –30°C). With the addition of 30 phr ASA terpolymer, the impact strength of the blends increased by almost 45 times at 23°C and 29 times at 0°C compared with the neat PVC, respectively. Herein, ASA terpolymer particles were related to each other to form a percolation group and the stress field around the ASA particles was connected with each other, thereby more effectively served as the stress concentrators, exhibiting the highest toughening efficiency. In addition, the significantly improved toughness could also be attributed to the special core-shell structure of ASA terpolymer, as well as, a good miscibility between the PVC matrix and the SAN shell of the ASA terpolymer. However, the decreasing temperature limited the flexibility of the PBA chain, resulting in the insignificant role of ASA terpolymer in toughening PVC at –30°C. Moreover, the improvement in the toughness of the blends did not sacrifice its heat distortion temperature.

Synthesis and optical properties of PVC-CdS-based nanocomposites

Poly(vinyl chloride) (PVC)–cadmium sulfide (CdS) nanocomposite films were successfully synthesized by ex situ solution casting method. Scanning electron microscopy showed that CdS nanoparticles are well monodispersed in the PVC matrix. From the ultraviolet (UV) spectra of nanocomposites, the width of the forbidden band for polymer nanocomposites was determined by extrapolation method. UV-visible optical spectra revealed that the optical band of nanocomposites is increased with increasing concentration of CdS nanoparticles in the PVC matrix. It was found that the band gap is 3.8 eV for PVC-3% CdS nanocomposites, 2.7 eV for PVC-5% CdS, and 2.35 eV for PVC-10% CdS nanocomposites. Photoluminescence spectrum of PVC-CdS-based nanocomposites shows two luminescent peaks at the wavelengths of 436 nm and 472 nm at the luminescence spectrum which belongs to CdS nanoparticles. Photoluminescence study shows that PVC-CdS nanocomposites exhibit a great blue shift (approximately 100 nm) compared with bulk CdS nanoparticles.