PVC Matrix Research Articles

Facile synthetic route for the preparation of PVC/α-MnO2-PVA nanocomposites: morphology, thermal, mechanical and Cd(II) adsorption properties

This study deals with the effect of α-MnO2-PVA as filler for improving the optical, mechanical, thermal, adsorption capacity and self-extinguishing properties of poly(vinyl chloride) (PVC) matrix. Therefore, α-MnO2 nanorods were obtained successfully by a hydrothermal method and were modified with poly(vinyl alcohol) (PVA) to increase compatibility of α-MnO2 with the organic PVC matrix and reduce the accumulation. Accordingly, PVC/α-MnO2-PVA nanocomposites (NCs) were fabricated with different amounts of modified nanorods (1, 3 and 5 wt%) by ultrasonic irradiation technique. Samples were characterized by instrumental analyses such as FT-IR, XRD, FE-SEM and TEM. Properties of NC films and neat PVC were evaluated with different techniques. Also, the PVC/α-MnO2-PVA NC was used as an efficient adsorbent for the removal of cadmium. It was found that PVC/α-MnO2-PVA NCs have better thermal, optical, tensile and self-extinguishing properties relative to pure PVC. The results from adsorption experiment showed that prepared NC is an effective adsorbent for the removal of Cd ions from aqueous solutions.

Mefenamic Acid Selective Membranes Sensor and Its Application to pharmaceutical Analysis

PVC membrane sensor for the selective determination of Mefenamic acid (MFA) was constructed. The sensor is based on ion association of MFA with Dodecaphospho molybdic acid (PMA) and Dodeca–Tungstophosphoric acid(PTA) as ion pairs. Nitro benzene (NB) and di-butyl phthalate (DBPH) were used as plasticizing agents in PVC matrix membranes. The specification of sensor based on PMA showed a linear response of a concentration range 1.0 × 10–2 –1.0 × 10–5 M, Nernstian slopes of 17.1-18.86 mV/ decade, detection limit of 7 × 10-5 -9.5 × 10 -7M, pH range 3 – 8 , with correlation coefficients lying between 0.9992 and 0.9976, respectively. By using the ionphore based on PTA gives a concentration range of 1.0 × 10–4 –1.0 × 10–5 M, Nernstian slope of 17.18-18.4 mV/ decade, limit of detection 8.0 × 10–6-9.3 × 10-5M,pH range 3 – 8 and correlation coefficients range between 0.9984 and 0.9891, respectively. The measurement interferences in the presence of Li+, Na+, Mg2+ Ca2+, Fe3+and Al3+ were studied using separate and match potential methods for selectivity coefficient determination. The method was applied for the determination of Mefenamic Acid in pharmaceutical preparations

Evaluation of dosimetric characteristics of graphene oxide/PVC nanocomposite for gamma radiation applications

Abstract Graphene oxide-polyvinyl chloride composite was prepared using tetrahydrofuran solvent-assisted dispersion of characterized nano flakes of graphene oxide in polymer matrix. Electrical percolation threshold of GO/PVC nanocomposite was determined via a finite element simulation method with a 2D model and compared with experimental results. A conductive cell with two silver coated walls was designed and fabricated for exploring dosimetric properties of the composite. Some characteristics of the new nanocomposite such as linearity of dose response, repeatability, sensitivity and angular dependence are investigated. According to 2D proposed method, obtained data associated to electrical conductivity of the GO/polymer composite for PVC matrix plotted in different GO weight percentages and had good compatibility (validity) with experimental data. The dose response is linear in the 17–51 mGy dose range and it can be introduced for gamma radiation dosimetry in diagnostic activities.

Photon correlation dynamics of unentangled star-shaped poly(ε-caprolactone)s with extremely small branches and its interaction with plasticization in miscible blend system

The dynamic effects of unentangled star-shaped polymers with extremely small branches on the plasticization of miscible polymer blends are investigated using ultra-small branched star poly(ε-caprolactone)s (USB-SPCLs), poly(vinyl chloride) (PVC), and their blends. Photon correlation dynamics of USB-SPCLs supports our previous suggestion that a whole USB-SPCL molecule acts as a single coarse-grain unit with dynamically-equivalent branches because of the extremely small branches, resulting in the total-molecular-weight-dependent Rouse dynamic behaviors of USB-SPCLs, regardless of the molecular architectures. The dynamic light scattering intensity autocorrelation curves of miscible PVC/USB-SPCL blends reveal that strong intermolecular interactions between PVC and USB-SPCL molecules determine the dynamic homogeneous behaviors of the blends despite their significantly different mobilities. The molecular motions of the blends depend on the total-molecular-weight-dependent Rouse dynamic behaviors of USB-SPCLs. These dynamic results clearly show the plasticization of the entangled neat linear PVC matrix by distinctive and rapid molecular mobility of USB-SPCLs.

Antimicrobial, mechanical, optical and thermal properties of PVC/ZnO‐EDTA nanocomposite films

Covalent surface functionalization of synthesized ZnO nanoparticles (NP)s with ethylenediaminetetraacetic acid (EDTA) was successfully carried out. Modified ZnO‐EDTA NPs as a viable and inexpensive filler were incorporated into poly(vinyl chloride) PVC matrix after their chemical modification to investigate the agglomeration behavior. All prepared materials including modified NPs and PVC/ZnO‐EDTA nanocomposites (NC)s were analyzed by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, thermogravimetric analysis, X‐ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. Fabricated PVC/ZnO‐EDTA NCs were reported to have high transparency and improved mechanical properties compared with PVC. Modified ZnO and the fabricated NCs were shown to exhibit excellent antibacterial activity against two bacteria species: Escherichia coli and Staphylococcus aureus. The obtained NCs could be considered as self‐extinguishing materials on the basis of the LOI values. Copyright © 2016 John Wiley & Sons, Ltd.

Properties of UV protective films of poly(vinyl-chloride)/TiO2 nanocomposites for food packaging

This work studies the UV protection properties of poly(vinyl-chloride) (PVC) nanocomposites. A functional property of UV protection is achieved by adding the active component (titanium dioxide (TiO2) or titanium dioxide modified with silver nitrate and copper nitrate) to the PVC matrix. PVC nanocomposites were prepared by extrusion and then pressed into films. Prepared PVC nanocomposites were characterized by thermogravimetric analysis, UV–Vis spectroscopy, X-ray diffraction and scanning electron microscopy. The mechanical properties and antimicrobial activity were also studied. The results show that PVC nanocomposites’ thermal stability is improved in relation to a pure PVC polymer. The thermal stability and antimicrobial efficiency increase when higher silver nitrate content is used. The sample prepared with silver and copper nitrate shows the best thermal stability due to a modified mechanism of thermal degradation. Samples where nanoparticles are homogeneously dispersed in the polymer matrix show good mechanical properties. The results also show that adding the active component TiO2 modified with silver ions contributes to the improved UV protection property of nanocomposite materials.

Plasticizer migration from micro-layered flexible poly (vinyl chloride) films prepared by multi-layer co-extrusion technology

Multi-layer flexible PVC films used in this study were produced via the micro-layer co-extrusion technology and the influences of micro-layer co-extrusion technology on plasticizer migration of flexible PVC were investigated. It was shown that the morphology of PVC molecule chains changed from the coiled state into the linear ordered state. The linear alignment is more compact with evenly dispersed additives in the PVC matrix after micro-layer co-extrusion. The volatility stability, solvent extraction stability, exudation stability, and film tensile strength were tested. The results indicated that, films made by micro-layer co-extrusion technology showed excellent plasticizer migration stability and mechanical properties, due to the ordered PVC molecule chains and the even additive dispersion.

Morphology and mechanical properties of PVC/straw‐fiber coated with liquid nitrile‐butadiene rubber composites

ABSTRACTThis study exhibited an approach of high‐value utilization of straw fiber (SF) in polymer composites. The rigid poly(vinyl chloride) [PVC]/SF and PVC/SF coated with liquid nitrile‐butadiene rubber (PVC/LNBR‐SF) composites were both fabricated by melt mixing. The chemical structure and crystal structure of LNBR‐SF were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and X‐ray diffraction (XRD). The mechanical properties and micro‐structure of PVC/SF and PVC/LNBR‐SF composites were also studied. FTIR and XRD results showed that the chemical structure and crystal structure of SF did not change after modifying with LNBR. The mechanical properties analysis showed that the PVC/LNBR‐SF composites exhibited better tensile strength, elongation at break and notched impact strength than those of PVC/SF composites owing to the compatibilization and toughening effect of LNBR. Scanning electron microscope results indicated that the LNBR improved the dispersion of SF in PVC matrix to some extent. The interface adhesion between SF and PVC matrix with adding LNBR was also enhanced. These results suggested that PVC/LNBR‐SF composites exhibited promising potential for practical application in substitute for wood. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44119.

Cu nanoparticles/PVC Composites: Thermal, Rheological, and Antibacterial Properties

AbstractThe effect of Cu nanoparticle (NP) content (0.3–3.0 wt%) on antibacterial, thermal, and rheological properties of PVC composites prepared by melt blending method was investigated. The composites were characterized by scanning electron microscopy (SEM) with energy dispersive X‐ray spectroscopy (EDX), transmission electron microscopy (TEM), capillary rheology, thermogravimetric analysis (TGA), and inductively coupled plasma atomic emission spectroscopy (ICP‐OES). A homogeneous distribution of copper on the composite surface was observed by SEM‐EDX. TEM images of Cu NPs/PVC composite films showed well‐dispersed and distributed Cu NPs and microparticles in the PVC matrix, but the size of particles increased with increasing copper content. The shear thinning and power law behavior was observed for all samples. At low shear rates (100 s−1) apparent viscosity of composites with copper loading lower than 1.2 wt% exhibited a “ball bearing” effect. The Cu particles enhanced the thermal stability of Cu NPs/PVC composites compared with neat PVC. The release of copper ions from Cu NPs/PVC composite films into the aqueous medium was negligible after 6 h of immersion. Polymer films with Cu NP amount higher than 0.6 wt% showed a similar kinetics of bacterial growth; therefore, a substantial improvement of antimicrobial activity was not observed with increasing Cu NP content.

Mechanical properties, flame retardancy, and smoke suppression of lanthanum organic montmorillonite/poly(vinyl chloride) nanocomposites

ABSTRACTA dimethyl dioctadecyl ammonium chloride modified organic montmorillonite (OMMT‐I.44P)/poly(vinyl chloride) (PVC) nanocomposite and anionic‐surfactant‐modified lanthanum organic montmorillonite (La‐OMMT)/PVC nanocomposites (with three different anionic surfactants for the La‐OMMTs) were prepared via melt‐intercalation technology. The effects of the La‐OMMTs and OMMT‐I.44P on the mechanical properties, flame retardancy, and smoke suppression of PVC were studied. X‐ray diffraction characterization showed that the La‐OMMTs were exfoliated in the PVC matrix. The mechanical properties of the nanocomposites were enhanced by the incorporation of the La‐OMMTs. Cone calorimetry and gas chromatography–mass spectrometry analyses indicated that the incorporation of the La‐OMMTs enhanced the flame retardancy and smoke suppression of the PVC nanocomposites. Scanning electron microscopy photos further showed that the residual char surfaces of La‐OMMT/PVC were all intact and, thus, provided better barriers to energy and smoke transport. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43951.

Etoricoxib selective sensor based on uracil-5,6-diamino-2-thio hydrochloride as neutral carrier for potentiometric analysis in pharmaceutical preparations

<em><span>A construction and electrochemical behavior of novel potentiometric membrane sensor responsive to the etoricoxib was described. The sensor was based on the ion-pair complex of etoricoxib (ET) with Uracil-5,6-diamino-2-thio hydrochloride UDTH (ET-UDTH) as exchange sites in a PVC matrix with different plasticizers dibutylphthalate (DBP) (electrode B) tri-n-butylphosphate (TBP) (electrode C), and dioctylphthalate (DOP) (electrode A). The electrodes exhibited near-Nernstian response for ET-UDTH over the concentration range 0.051-40.042 mM. The electrode offered significant advantages including long lifetime (about 2 months), excellent stability and reproducibility, good response time (10-25 s), and wide pH working range (pH 5-12). Selectivity coefficients of ET related to a number of interfering cation and some organic compounds were investigated, and there were negligible interference caused by most of the investigated species. The direct determination of 0.5-10 mM of ET showed an average recovery of 99.03-101.75% and a mean relative standard deviation 0.40-1.88. The results were obtained by determination of ET in tablets using the proposed electrodes which were comparable favorably with those obtained by spectrophotometric method</span></em>

Thermal decomposition kinetics of silane treated wood: PVC microcellular composites

Thermal degradation of PVC and acacia wood flour (with and without silane treatment) composites was studied by using TGA in nitrogen atmosphere. The wood flour was varied from 10 to 30 % within the PVC matrix. Thermal stability of the composites increased with increase in percentage of wood flour at higher temperature. The thermal stability of the silane treated microcellular composites (SPVC) was found to be greater than that of the untreated (UPVC) one. It was also strengthened by the higher activation energy of the silane treated composites for 30 % (SPVC30) and 10 wt% (SPVC10) filler loading (210 and 187 kJ mol−1) in comparison to that of UPVCs (185 and 161 kJ mol−1) respectively. The isothermal degradation and thermodynamic parameters were also studied and found that the isothermal stability with time, entropy change (ΔS) and enthalpy change (ΔH) increased with increase in wt% of UPVCs and SPVCs . The values of ΔH were recorded as 534 and 452 kJ mol−1 for SPVC30 and SPVC10, which were highest among all the composites. It proved the better thermal stability of silane treated over the untreated microcellular composites. The values of Gibb’s free energy (ΔG) decreased as the filler content increased from 10 to 30 wt% filler loading, which supports the above said statements.

Activity Coefficient Modeling of Ionic Liquids in Water Based on Ion Selective Electrode Potential Measurements

Two ion selective membrane electrodes were prepared based on the ionic liquids [BMIm]Br and [BMIm]BF4 as ion exchangers in a plasticized PVC matrix. These electrodes exhibit fast, Nernstian responses over a wide concentration range. The selectivity coefficient, detection limit, and calibration slope were determined for the electrodes. The proposed sensors were also utilized to obtain the mean activity coefficients of the studied ionic liquids in water using potentiometry. The data were correlated by the Pitzer and extended Debye–Huckel models.

Molecularly imprinted polymer based potentiometric sensor for the determination of 1-hexyl-3-methylimidazolium cation in aqueous solution

The molecular imprinting technique is powerful to prepare functional materials with molecular recognition properties. In this work, a potentiometric sensor was fabricated by dispersing molecularly imprinted polymers (MIPs) into plasticized PVC matrix and used for the determination of 1-hexyl-3-methylimidazolium cation ([C6mim]+) in aqueous solution. The MIPs were synthesized by precipitation polymerization using 1-hexyl-3-methylimidazolium chloride ([C6mim]Cl) as the template molecule, methacrylic acid (MAA) and ethylene glycol dimethacrylat (EGDMA) as the functional monomers, and EGDMA also as the cross-linking agent. The as-prepared electrode exhibited a Nernstian response (58.87 ± 0.3 mV per decade) to [C6mim]+ in a concentration range from 1.0 × 10−6 to 0.1 mol kg−1 with a low detection limit of 2.8 × 10−7 mol kg−1, high selectivity, and little pH influence. The as-prepared electrode was used for the detection of the [C6mim]+ in distilled water, tap water, and river water with a good recovery. It was also successfully applied in the determination of mean activity coefficients of [C6mim]Br in fructose + water systems based on the potentiometric method at 298.15 K.

Preparation of zinc hydroxystannate-decorated graphene oxide nanohybrids and their synergistic reinforcement on reducing fire hazards of flexible poly (vinyl chloride).

A novel flame retardant, zinc hydroxystannate-decorated graphene oxide (ZHS/GO) nanohybrid, was successfully prepared and well characterized. Herein, the ZHS nanoparticles could not only enhance the flame retardancy of GO with the synergistic flame-retardant effect of ZHS but also prevent the restack of GO to improve the mechanical properties of poly (vinyl chloride) (PVC) matrix. The structure characterization showed ZHS nanoparticles were bonded onto the surface of GO nanosheets and the ZHS nanoparticles were well distributed on the surface of GO. Subsequently, resulting ZHS/GO was introduced into flexible PVC and fire hazards and mechanical properties of PVC nanocomposites were investigated. Compared to neat PVC, thermogravimetric analysis exhibited that the addition of ZHS/GO into PVC matrix led to an improvement of the charring amount and thermal stability of char residue. Moreover, the incorporation of 5 wt.% ZHS/GO imparted excellent flame retardancy to flexible PVC, as shown by increased limiting oxygen index, reduced peak heat release rate, and total heat release tested by an oxygen index meter and a cone calorimeter, respectively. In addition, the addition of ZHS/GO nanohybrids decreased the smoke products and increased the tensile strength of PVC. Above-excellent flame-retardant properties are generally attributed to the synergistic effect of GO and ZHS, containing good dispersion of ZHS/GO in PVC matrix, the physical barrier of GO, and the catalytic char function of ZHS.

Two series of inorganic melamine salts as flame retardants and smoke suppressants for flexible PVC

Two series of inorganic melamine salts containing a tungstate or molybdate were synthesized as a flame retardant and smoke suppressant for flexible PVC, and their flame retardancy and smoke suppression were studied by limiting oxygen index (LOI), smoke density rating (SDR) test, cone calorimeter, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). It can be found that the presence of melamine tungstate or melamine molybdate causes an obvious increase in LOI and a decrease in SDR. The cone calorimeter results reveal that melamine tungstate or melamine molybdate can clearly change the decomposition behavior of PVC and form a char layer on the surface of the composites, consequently resulting in efficient reduction of the flammability parameters, such as heat release rate, smoke production rate, total smoke production, and so on. The TGA and SEM results demonstrate that melamine tungstate can delay the degradation of PVC and improve the stability of the char residue. Moreover, melamine molybdate and the PVC matrix form a novel intumescent flame retardant and smoke suppression system, in which the PVC matrix acts as the carbonization agent and molybdate as the acid source (Lewis acid). Molybdate can catalyze the dehydrochlorination reaction and promote the crosslinking reaction of PVC effectively. Melamine (MA) and the released hydrogen chloride can act as the blowing agent, which enhance the intumescence of the char. POLYM. COMPOS., 39:529–536, 2018. © 2016 Society of Plastics Engineers

Production of PVC/α-MnO2-KH550 nanocomposite films: Morphology, thermal, mechanical and Pb (II) adsorption properties

α-MnO2 nanorods have been synthesized through a simple method without the presence of catalysts and templates. The prepared nanorods were employed as fillers to retrofit and increase the mechanical strength, thermal stability and adsorption properties of poly(vinyl chloride) (PVC) as one of the most important thermoplastics. To prevent accumulation and increase compatibility of α-MnO2 with the organic PVC matrix, the nanorods were modified with γ-aminopropyltriethoxy silane (KH550). Nanocomposites (NCs) were prepared with different amounts of modified α-MnO2 nanorods (1, 3 and 5wt%). FE-SEM and TEM characterization revealed that the α-MnO2 nanorods are in rod-like morphology with diameter of 40nm and uniformly dispersed in the PVC matrix. Optical behavior, thermal stability, tensile and self-extinguishing properties of the obtained NCs was studied, respectively. Removal of Pb(II) ion from aqueous solution by NCs was also performed through the flame atomic adsorption spectroscopy analysis. The results indicated that PVC/α-MnO2-KH550 NCs exhibit better thermal stability, tensile and self-extinguishing properties than pure PVC in three weight percent. The obtained results of adsorption revealed that the NC films could be used for the removal of Pb(II) ions from the aqueous medium.

Water absorption, biodegradation, thermal and morphological properties of Spartium junceum fiber-reinforced polyvinylchloride composites: effects of fibers content and surface modification

In this study, we want to investigate the effects of fibers content and surface modification of Spartium junceum (SJ) fibers on the water absorption characteristics, thermal degradation, and morphological properties of SJ-reinforced poly (vinyl chloride) (PVC) composites. In addition, the change in mechanical proprieties of the composites after biodegradation test was evaluated by tensile strength. In order to improve the interfacial interactions between the PVC matrix and the SJ fibers, SJ fibers were modified by sodium hydroxide (NaOH), vinyltrimethoxysilane (VTMS) and treated with sodium hydroxide solution followed by VTMS (NaOH+VTMS). The results show that the water uptake of PVC/SJ fibers composites increases with the increase in the fibers’ content. However, the surface modification reduces water uptake. Moreover, the results indicate that the kinetics of water absorption of the PVC/SJ fibers composites approaches the Fickian diffusion mechanism. Also, the results indicate that the tensile strength of the composites is affected by the biodegradation test and chemical treatments. The atomic force microscope pictures of the composites illustrate the reduction of roughness via surface treatments of fibers.

Effect of chemical and physical doping with iodine on the optical and dielectric properties of poly(vinyl chloride)

Iodination of poly(vinyl chloride) (PVC) was prepared by addition of I2 or I− through physical adsorption and chemical modification techniques forming (PVC–I2) (composite I) and (PVC–I−) (composite II), respectively.Investigations were performed using TGA, DSC, FTIR, UV–vis absorbance analyses and ac conductivity measurements. The activation energy of decomposition, ΔEd, was found to be 215.15kJ/mole and 43.1kJ/mole for PVC and composite II, respectively. Both direct and indirect optical transitions near the absorption edge are observed. Addition of I2 or I− decreases the optical energy gap for PVC. The chemical replacement of Cl− ion in PVC matrix with I− ion in composite II increases the electrical conductivity by two orders. A possible conduction mechanisms are suggested.

Photolysis of Isoelectronic Ruthenium Nitrosyl and Diazonium Complexes in Frozen PVC Matrices: Retention of Dinitrogen on Ruthenium Following Photochemical Phenyl Radical Loss

AbstractPhotolysis of RuCl3(η1‐NO)(PPh3)2 in poly(vinyl chloride) (PVC) matrices at 85 K results in reversible linkage isomerism of the nitrosyl ligand to form the isonitrosyl complex RuCl3(η1‐ON)(PPh3)2. Metal‐to‐ligand charge‐transfer (MLCT) excitation of the isoelectronic phenylazo complex, RuCl3(η1‐N2Ph)(PPh3)2, has previously been shown to result in generation of the phenyl radical, presumably through decomposition a photogenerated diazenyl radical. Examination of this photolysis in a PVC matrix at cryogenic temperatures has permitted direct observation of an isotopically sensitive product band that may be assigned to a 17‐electron ruthenium dinitrogen species, suggesting that this photochemical decomposition does not proceed through formation of a diazenyl intermediate but through homolytic cleavage of the parent diazonium complex to give the phenyl radical and the 17‐electron RuCl3(η1‐N2)(PPh3)2.