Mixture Of Polyvinyl Chloride Research Articles

Long-term presence of microplastics in aerobic and anaerobic sequential batch reactors: Effect on treatment, microbial diversity, and microplastics morphology

Sewage treatment plants (STPs) are identified as the significant sink and source of microplastics (MPs) in aquatic bodies and terrestrial systems. A major fraction of MPs gets retained in STPs for a longer duration, and their potentiality for secondary MPs generation and additives leaching remain under investigated. Therefore, this study focussed on the effect of long-term exposure of aerobic and anaerobic biological sewage treatment units on MPs, along with the effect of MPs on treatment efficiency and microbial consortium. A mixture of polyvinyl chloride, polystyrene, and nylon MPs at 262 MPs/L was spiked in the aerobic and anaerobic sequential batch reactors (SBRs) for 120 days at the start of study. The study revealed a release of noteworthy fraction of secondary MPs into the reactors from spiked MPs. At the end of 120th day, the presence of secondary generated MPs was estimated as 1000 ± 71 MPs/L and 650±141 MPs/L in aerobic and anaerobic SBRs respectively. Most of the observed secondary MPs were of size < 300 µm. Leaching of additives, i.e. cyclohexylamine, cyclotetradecane, octadecanol, pipericine etc., into the SBR effluents were also observed. The depuration capacities of the reactors were not affected with the presence of MPs during the study. While the microbial diversity and abundance were negatively impacted in aerobic SBRs, no such impacts were observed in anaerobic SBRs due to MPs. These results do suggest such exposures to potentially cause secondary MPs and chemical pollution in receiving matrices for the treated effluent, as well as effect on the native microbial community.

A single-step upcycling of PVC-containing municipal solid waste compositions for greener chemicals and clean solids as fuel or oil absorbent

Polyvinyl chloride (PVC) containing municipal solid waste (MSW) streams are difficult to recycle and mostly landfilled due to various detrimental effects PVC causes to waste recycling. In this work, a single-step upcycling of PVC-containing commingled wastes in tetrahydrofuran was investigated using cellulose, PVC, polyethylene (PE), polypropylene (PP), and polystyrene (PS) to model the wastes. During the co-conversion, in-situ produced HCl derived from PVC decomposition acted as an acid catalyst to selectively decompose cellulose into liquid mainly containing levoglucosan (LGA) and furfural. It was also found that the presence of PE, PP, and PS in the mixture synergistically enhanced the cellulose-derived monomer productions and increased the reaction rate for producing the monomers by suppressing secondary reactions of HCl in the solvent. The maximum LGA yield from co-conversion of cellulose, PVC, and PS was 35.4% after a 5 min reaction compared to the 31.7% obtained without PS in the mixture. In addition to converting cellulose to chemicals, PVC-derived polyaromatics and partly decomposed PE, PP, and PS were recovered as solids. The dechlorinated solids had higher heating values up to 46.11 MJ/kg, achieved by co-converting cellulose, PVC, and PP. When used as oil absorbents in water, the solid recovered from converting cellulose, PVC, and PE mixture showed the highest absorption capability. Overall, the presented approach offers a promising way for upcycling PVC-containing wastes in which PVC properties and its molecular structure are leveraged to enhance the conversion.

Sustainable Manufacturing Process Applied to Produce Waste Polymer-Polymer Matrix Composites

Getting rid of plastic and rubber waste is one of the goals of achieving a sustainable lifestyle. Out-of-service tires and fuel and water tanks manufactured from polyvinyl chloride (PVC) are the most common waste that cities suffer from. This paper aims to investigate the effect of reinforced waste polymer particles on the polyester resin matrix when producing polymer matrix composite materials from waste tires and damaged plastic water tanks with different polymeric percentages. The polymer matrix composite could be used later in different applications, such as insulators and vibration dampers. The composite materials were evaluated by measuring the Shore D hardness, tensile strength, modulus of elasticity, and coefficient of thermal conductivity. The overall results showed hopeful behavior. Mixing a specific mixture of waste PVC and tires with polyester and hardener gives a higher tensile strength, modulus of elasticity, and Shore D hardness compared to each material when used separately. The thermal conductivity values increase with the mixing conditions between the materials. The thermal conductivity values can be reduced by using higher percentages of a mixture of waste tires and polyester or PVC and polyester. A 4.5% PVC, 4.5% tire and 91% (polyester and hardener) mixture can be recommended to improve tensile strength performance. A mix of 8.3% PVC, 8.3% tire, and 83.4% (polyester and hardener) can be recommended for high hardness.

Innovative reference materials for method validation in microplastic analysis including interlaboratory comparison exercises

Reference materials (RMs) are vital tools in the validation of methods used to detect environmental pollutants. Microplastics, a relatively new environmental pollutant, require a variety of complex approaches to address their presence in environmental samples. Both interlaboratory comparison (ILC) studies and RMs are essential to support the validation of methods used in microplastic analysis. Presented here are results of quality assurance and quality control (QA/QC) performed on two types of candidate microplastic RMs: dissolvable gelatin capsules and soda tablets. These RMs have been used to support numerous international ILC studies in recent years (2019–2022). Dissolvable capsules containing polyethylene terephthalate (PET), polyvinyl chloride (PVC), polyethylene (PE), and polystyrene (PS), in different size fractions from 50 to 1000 µm, were produced for one ILC study, obtaining relative standard deviation (RSD) from 0 to 24%. The larger size fraction allowed for manual addition of particles to the capsules, yielding 0% error and 100% recovery during QA/QC. Dissolvable capsules were replaced by soda tablets in subsequent ILC studies and recovery test exercises because they were found to be a more reliable carrier for microplastic RMs. Batches of soda tablets were produced containing different single and multiple polymer mixtures, i.e., PE, PET, PS, PVC, polypropylene (PP), and polycarbonate (PC), with RSD ranging from 8 to 21%. Lastly, soda tablets consisting of a mixture of PE, PVC, and PS (125–355 µm) were produced and used for recovery testing during pretreatment of environmental samples. These had an RSD of 9%. Results showed that soda tablets and capsules containing microplastics >50 µm could be produced with sufficient precision for internal recovery tests and external ILC studies. Further work is required to optimize this method for smaller microplastics (< 50 µm) because variation was found to be too large during QA/QC. Nevertheless, this approach represents a valuable solution addressing many of the challenges associated with validating microplastic analytical methods.

Colorimetric and fluorimetric pH sensing using polydiacetylene embedded within PVC‐PCL nanofibers

AbstractThe applicability of model polydiacetylenes (PDAs) in hydrogen ions sensitive optodes was tested. Nanofibers mats were electrospun using a mixture of polyvinyl chloride (PVC) and polycaprolactone (PCL) together with 10, 12‐tricosadiynoic acid (TCDA) or 10,12‐pentacosadiynoic acid (PCDA). After the polymerization the mats were applied in colorimetric and fluorimetric pH sensors. The PDAs were formed by photopolymerization with a UV lamp (254 nm), resulting in a change of mats color from white to dark blue. The morphology of both fiber mats is similar (SEM images), and the average diameters of fibers were estimated as equal to 228±73 and 248±61 nm for TCDA and PCDA, respectively. As the pH increases, the color of the fiber mat changes from blue to red and the process can be followed visually. The result obtained by computer image analysis showed a sigmoidal increase in the intensity of red and a decrease in the intensity of blue color with increasing pH. A similar sigmoidal response is observed for the dependence of the emission intensity on the pH. Changes in the recorded signal occur in the pH range from 7 to 8.5 or from 8 to 9.5 for mats with TCDA and PCDA, respectively. Both readout modes can be successfully used for pH sensing with proposed nanofibrous mats in the range of pH close to the physiological pH range.

Study of the Properties of the Composition Obtained Based on Mixtures of Polyvinyl Chloride and Ethylene-Propylene Copolymers

The properties of mixtures and vulcanizates of polyvinyl chloride (PVC) and ethylene-propylene elastomers (SKEPT-40) with functional group polymers have been studied and it appears that the effectiveness of the application of functional group polymers (FQP) is characterized by the improvement of the complex properties of vulcanizates. As shown, among the FQP, the industrial scale production of PVC and the low cost of its use in the purchase of rubber mixtures based on SKEPT have been developed. In this regard, new composition mixtures were obtained by replacing the main polymers in rubber mixtures with 5÷30 mass parts of PVC based on SKEPT. The physical and mechanical properties of their technological and vulcanizates were studied. Experiments show that the sol-fraction and durability of vulcanizate in gasoline, gasoline-benzene (3:1) mixture, and metaxylol decrease with the increase of PVC content. The reduction of the sol-fraction of the vulcanizate can be explained by the low swelling of PVC in the above-mentioned solvents. Therefore, the vulcanizate based on the SKEPT PVC mixture has a higher resistance to oil and gasoline than the vulcanizate based on unmodified SKEPT. It is learned that 10 mass. h to SKEPT. When PVC is included, the degree of swelling of the vulcanizate is reduced by 20% in gasoline, in the mixture of gasoline-benzene (3:1), M-xylene, and “, Avtol” oil, compared to the vulcanizate based on SKEPT. 30 c.h. and when included, the degree of swelling of the vulcanizate decreases by 2.7 times in gasoline, 2.3 times in gasoline-benzene (3:1) mixture, and 3.2 times in “Avtol-10” oil.

Study of the Properties of the Composition Obtained Based on Mixtures of Polyvinyl Chloride and Ethylene-Propylene Copolymers

Study of the Properties of the Composition Obtained Based on Mixtures of Polyvinyl Chloride and Ethylene-Propylene Copolymers

Enhanced flotation of high density polyethylene and polyvinyl chloride mixtures based on clean corona modification

The dramatic increase in waste plastics has caused harm to both human health and the environment. Due to the variety of plastic products and their complex components, it is a technical challenge to effectively separate them. High density polyethylene (HDPE) and polyvinyl chloride (PVC) both have a high detection frequency in the common solid waste streams like automobile shredder residue (ASR), and due to the similar properties of different plastics, their mixtures lack reliable separation methods. Specifically for this kind of mixtures, this work provided a novel separation strategy with prepositive corona modification and postpositive flotation units. To obtain the optimal separation parameters, flotation performance of HDPE and PVC were investigated under different modification conditions controlled by the corona polarity, discharge power and exposure time. Besides, the modification mechanism was revealed through multi-characterization tests on surface morphology, molecular weight, contact angle, and spectrums. The results showed that corona discharge can generate non-thermal plasma to activate the surfaces of HDPE and PVC, thereby increasing their floatability difference. Under the optimal conditions of 300 W positive discharge power and 8000 ms exposure time, HDPE turned into the sinking tail while PVC still accumulated in the floating product, leading to the maximum separation recovery and purity of 96.36% and 97.01%, respectively. Amorphous low-molecular weight oxidic substances emerged on the upper layer of polymers was verified by the multi-characterization, representing in varying degrees of oxidation and chain scission (HDPE > PVC). Since the corona modification is reagent-free-addition and rapid in-line process, this work showed great advantages in the total cost of separation (only 450.03 USD/t) and potential environmental benefits, which also paves a clean way for the recycling of HDPE and PVC.

Mechanical and physical characteristics of alkali- activated mortars incorporated with recycled polyvinyl chloride and rubber aggregates

One of the ways to achieving net-zero concept in the construction industry is to use alternatives to Portland cement (OPC) and virgin aggregates for concrete manufacturing. Recycled rubber and polyvinyl chloride (PVC) aggregates in conjunction with low-carbon binders can be potentially utilised to substitute natural sand and reduce the negative environmental impacts of OPC. A replacement of natural sand (up to 70% by volume) in alkali-activated materials (AAMs) with recycled rubber and PVC particles derived from tyre waste and insulation coating of electric wires, respectively, was investigated in this study. The performance of developed AAMs was evaluated using a comprehensive testing program including mechanical, physical and microstructure assessments. AAM composites with PVC and rubber particles outperformed natural aggregate composites in terms of thermal resistivity, water absorption, volume permeability voids (VPV), and high-frequency sound insulation. Results showed that 70% PVC mixture achieved the lowest water absorption rate and thermal conductivity with a reduction of 73% and 20%, respectively, compared to the control mixture. A maximum reduction of 34% in VPV was observed in the 70% rubber mixture when compared to the control mixture. In terms of mechanical properties of waste stream aggregates, PVC outperformed rubber. The results showed that 30% replacement of PVC and rubber would produce composites with 7-day compressive strengths of 35 MPa and 25 MPa, respectively, which can be used to produce high-load bearing structures. The Energy-dispersive X-ray Spectroscopy (EDX) was performed to detect chloride leaching from PVC aggregates, where results indicated that no leaching had occurred after more than 90 days of casting. Regarding the carbon emission, the carbon footprint of AAM composites is decreased by using the polymeric fractions in place of sand. The developed composites of this study can be used safely in non-load bearing structural elements with promising physical and mechanical performance.

Direct tensile test evaluation and characterization for mechanical and rheological properties of polymer modified hot mix asphalt concrete

AbstractUsing polymer to modify asphalt binder for better performance has become popular in pavement engineering, for which to evaluate the effect of polymer addition on the properties of the asphalt concrete is essential for mix design. Conventional mechanical test methods, primarily using bending of beams and indirect splitting, are not only materially and timely costly and labor intensive but also provide no direct information for the viscoelastic and rheological characteristics of the materials. This paper reports a study using direct tensile test (DTT) to evaluate the effect of polymer on both mechanical and rheological properties of modified asphalt concrete. Two types of polymers, which are styrene‐butadiene‐styrene (SBS), and a mixture of SBS and polyvinyl chloride (PVC), were investigated on two mixes using fine and coarse aggregates, respectively. It has been found that SBS generates improvement for both mechanical and rheological properties of hot mix asphalt concrete. However, using a hybrid mixture of SBS and PVC shows that PVC can further improve the mechanical properties, but deteriorate the toughness of the asphalt concrete. At the end, a simple quadric polynomial model has been proposed to characterize the combined SBS and PVC effects for the sake of the guidance for mix design.

Enhancement of BTX production via catalytic fast pyrolysis of almond shell, olive pomace with polyvinyl chloride mixtures

This work addresses enhanced benzene, toluene and xylene (BTX) production by catalytic fast co-pyrolysis from agroindustrial biomass blended with PVC and the use of prepared NaZSM-5 and HZSM-5. Results from catalytic fast pyrolysis of biomass indicates that oxygen-containing compounds decreased whereas aromatics increased. The catalytic effect of mineral content altered the co-pyrolysis intermediates by increasing the formation of mono-aromatics while reducing poly-aromatic hydrocarbons. Furthermore, the addition of PVC strongly influenced thermal decomposition of agricultural waste biomass, where BTX yields were enhanced up to 26.6% and 25.1% for 1:2 OP/PVC-HZ and 1:2 AS/PVC-HZ, respectively. Yields of toluene and xylene peaked at 19% and 10.5% hydrocarbon yields with 1:2 OP/PVC-HZ blend. Additionally, from the pyrolytic gas, CH4 yields increased while the CO2 yield fell due to oxygen removal by decarboxylation. These findings could provide a great insight into the olive pomace and almond shell valorization through an inexpensive and straightforward easy process.

Evaluation of Elastic Modulus of Mixtures of Polyvinyl Chloride with a Number of Synthetic Polymers

Evaluation of Elastic Modulus of Mixtures of Polyvinyl Chloride with a Number of Synthetic Polymers

ПРИМЕНЕНИЕ ТЕРМОРАСШИРЕННОГО ГРАФИТА В ПАСТАХ ДЛЯ ТРАФАРЕТНОЙ ПЕЧАТИ ЭЛЕКТРОХИМИЧЕСКИХ СЕНСОРО

This paper presents the graphite-based paste, within which an exfoliated graphite as the main electrically conductive component was selected. The resulting graphite-based paste is a homogenous polyvinyl chloride mixture containing carbon materials with different particle sizes (such as gas soot and microcrystalline graphite). The preparation of electrical conductivity graphite-based paste and electrode sample based on it and obtained by means of screen printing technology. The purpose of electrode properties exploration is to elucidate its applicability as a main component of electrochemistry biosensor for glucose concentration measurements in blood. The results of a comparative analysis of printed electrodes based on it with electrodes made of commercial graphite paste from one of the world's leading manufacturers (Gwent Electronic Materials) are presented. The obtained electrodes were characterized by comparable physical and electrochemical parameters. According to the results of scanning electron microscopy of electrodes, graphite paste with exfoliated graphite is suitable for screen printing. The electrical resistivity of the electrodes with exfoliated graphite was 440 (Ohms·mm2)/m, and the electrodes obtained on the basis of commercial paste – 270 (Ohms·mm2)/m. The biosensor, made on the basis of the original graphite paste, is characterized by a wide range of linearity of response to glucose in the range from 1 to 40 mM, and similar values of currents and sensitivity compared to a commercial analogue. The results of studies of the obtained electrodes have shown that exfoliated graphite is a promising material for use in electrochemical systems, and reducing the concentration of carbon conductive components can significantly reduce the cost of finished graphite paste and increase its commercial potential.

Compatibilization of polyvinyl chloride ‐ polymethyl methacrylate polymer blends with maleic anhydride‐styrene‐methyl methacrylate terpolymer

AbstractIn this study, nonmiscible polyvinyl chloride (PVC) and polymethyl methacrylate (PMMA) polymers were made miscible by using MA‐St‐MMA terpolymer as a compatibilizer. Maleic anhydride‐styrene‐methyl methacrylate (MA‐St‐MMA) terpolymer was synthesized in our laboratory and used. The synthesized terpolymer was determined by FT‐IR spectroscopy. Equal mass PVC/PMMA mixture samples were prepared in series and the compatibilizer terpolymer varying between 2% and 10% by mass was added to the samples and the effect of the added terpolymer on the miscibility was determined viscometrically, thermally, mechanically and, visually. With the addition of the compatibilizer, the two components in the mixture behave like a single polymer with a single glass transition temperature (Tg) and the mixture became compatible. As a result of viscometric experiments, it has been determined that with the added MA‐St‐MMA terpolymer, the Δb value derivated from the Krigbaum‐Wall equation which is the miscibility parameter of a mixture shifted into the positive (+) zone indicating that the two polymers became miscible. By visual analysis, it was observed that the added terpolymer reduced the opaque appearance and the phase separations of the mixture. From the tensile test, a significant improvement in impact toughness was observed. When all the data obtained were evaluated, it was determined that the synthesized MA‐St‐MMA terpolymer was a suitable compatibilizer for the mixture of PVC and PMMA.

Dust distribution of solid and adhesive mixed dust in a granular bed filter

Granular bed filters can effectively filter adhesive dust in high-temperature flue gas. In this study, polyvinyl chloride (PVC) powder was used as adhesive dust, and the mixture of PVC and ash powder was used to simulate solid and adhesive mixed dust. The effects of gas temperature, velocity, and inlet adhesive dust mass content on dust distribution in granular bed (GBF) were discussed. Results show that the mixed dust mainly accumulates on the upper part of the granular bed, and the mass of the collected dust decreases exponentially from the upper layer to the bottom layer in the GBF. The adhesive dust content collected in each layer differs from that of the incoming dust, and their deviation varies approximately linearly along with the depth of the bed. The total dust distribution and adhesive dust content deviation are influenced by gas temperature and inlet adhesive dust content but independent of gas velocity. The correlations of dust distribution of solid and adhesive mixed dust are presented based on the experimental results.

Development of Equipment for Injection Molding of Polymer Products Filled with Recycled Polymer Waste.

Polymer waste of light industry and other industries is processed by chemical recycling and mechanical grinding. Modern equipment for polymer waste processing has the following drawbacks: significant energy consumption and reduced performance properties of recycled polymer. New technological processes and equipment for polymer waste recycling have been developed for the manufacture of light industry polymer products with increased performance characteristics. The manufacturing of such products was made possible by the development of the mathematical model, which describes the movement of a mixture of main polymer material and particles of recycled polymer waste in the process of filling a mold cavity. The model, in contrast to the existing models, allows observing the formation of the polymer product structure containing recycled waste particles. Improvement in the performance characteristics of shoe soles made by the injection molding of a mixture of polyvinylchloride and particles of recycled polyvinylchloride was confirmed by experimental tests of breaking strength and fatigue life. The results of these tests can be used in the design of processing equipment to obtain waste particles of the required shape and size and in the design of molds to provide the required concentration and orientation of waste particles in light industry polymer products.

Experimental and numerical analysis of a new tribo-electrostatic separator with coaxial cylindrical electrodes for plastic binary granular mixtures

This paper is aimed to the description of a new tribo-electrostatic separation process where the top part of the separator is constituted by two coaxial electrodes and the bottom part comprises two cone-shaped electrodes. An experimental and a numerical analysis were carried out in which the main significant factors were investigated. The experiments carried out on three different binary mixtures of mm-size PA (polyamide), PC (polycarbonate) and PVC (polyvinyl chloride) particles showed that more than 80% of the total mass is recovered with high purity values up to 90%.

Pyrolysis of wood and PVC mixtures: thermal behaviour and kinetic modelling

Wood waste containing halogenated compounds such as polyvinyl chloride (PVC) is in abundant supply, although the pyrolysis of such waste feedstock for energy production may cause corrosion and environmental problems due to the release of HCl gas. Hence, there is a need to understand the pyrolysis behaviour of chlorine-contaminated wood in order to develop methods that minimise the impact of chloride species on pyrolysis equipment and product quality. In literature, few studies exist on the kinetic analysis of wood and PVC co-pyrolysis. The existing models assume a single-step reaction with an n-order reaction mechanism for the entire process, which may lead to large errors in the kinetic parameters estimated. Therefore, in this paper, we develop and validate a multi-step kinetic model that predicts the pyrolysis behaviour and reaction mechanism of poplar wood (PW) pellet with different contents of PVC (0, 1, 5, 10, 100 wt%). Using data from thermogravimetric analysis of the pellets at heating rates of 5, 10 and 20 °C/min, we determined the apparent kinetic parameters by combining Fraser-Suzuki deconvolution, isoconversional methods and master plot procedures. Our model fitted the experimental data well with a deviation of less than 4.5%. Our results show that the addition of 1 wt% PVC to PW decreases the activation energy of hemicellulose and cellulose pyrolysis in PW from 136.3 to 101.6 kJ/mol and from 216.7 to 108.2 kJ/mol, respectively. This demonstrates the importance of acid hydrolysis reactions between the cellulosic fibres of PW and HCl released from PVC dehydrochlorination. Furthermore, we found that a nucleation and growth mechanism best represents the rate-limiting interactions between PVC and PW, which we linked to the formation of metal chloride crystals from acid-base reactions between HCl and PW minerals. Our kinetic model is an improvement of current models for the co-pyrolysis of wood and PVC, and can be readily used in a reactor-scale model of a pyrolyser or gasifier due to its relative simplicity.

Experimental Modeling and Optimization of a Free-Fall Electrostatic Separator Equipped With Four Rotating-Cylinder Electrodes

The four-cylinder electrostatic separator is a recent improvement of the “standard” free-fall equipment. The new design, which drastically reduces the inconveniences related to the impacts that might occur between the particles and the electrodes, has been adapted for applications involving the processing of micronized particles. Such applications require the use of a specific rotating-blade-type tribocharging device and an appropriate electrode cleaning system. The aim of the present work is to evaluate the effects of several factors that influence the performances of the new triboelectrostatic separator. The experiments were made on a binary mixture of polyvinyl chloride (PVC) and unplasticized PVC. The control variables considered in this study were the rotating speed of the central cylinder of the tribocharging device, the voltage applied to the electrodes of the separator, and the distance between them. The results obtained were excellent: The recovery rates and the purities of the separated products exceeded 95% for the optimum values of the control variables.

Polyvinyl chloride-based polymer blends (overview)

Polymer mixtures of polyvinyl chloride with various classes of polymeric materials are considered. The classifi cation of mixtures is proposed. The compositions of the mixtures are given. The eff ect of introduced additives on the properties of polymers is determined. Examples of the practical use of polymer compositions are given.