Virgin Polyvinyl Chloride Research Articles

The environmental costs of clean cycles: Quantitative analysis for the case of PVC window profile recycling in Germany

AbstractRecycling schemes for long‐lived products are challenged by the presence of “legacy substances,” which have been used in production in the past, but are nowadays classified as substances of concern. This study quantitatively evaluates the trade‐offs between phasing out legacy substances, increasing circularity levels, and reducing life cycle impacts of polyvinylchloride (PVC) window profiles recycling in Germany based on a comprehensive dynamic material and substance flow analysis coupled with a prospective life cycle assessment. Scenario results indicate that although lead had been phased out in virgin PVC by 2015, lead concentrations in end‐of‐life PVC window profiles will remain above 0.3% until the end of the century without a restriction of lead in recycled PVC and will be by factor 3–5 higher compared to a restriction as stipulated by EU 2023/923. However, the latter is associated with lower recycling rates and higher life cycle environmental impacts of PVC window frame waste management, which cannot be fully compensated by the introduction of new waste treatment pathways using currently available technologies. The study serves to introduce a new comprehensive modeling framework, which allows for the consideration of trade‐offs between substance, material, and environmental impact dimensions as a basis for discussing and developing sustainable waste management strategies.

Adsorption Behavior and Mechanisms of Trihalomethanes onto Virgin and Weathered Polyvinyl Chloride Microplastics.

Microplastics that adsorb various toxic contaminants in water may be transported into cells and organs, possibly posing toxicological risks in the aquatic environment. Disinfection byproducts (DBPs), which are ubiquitous in chlorinated drinking water and wastewater, may have some potential to sorb onto microplastics (MPs) through hydrophobic or electrostatic interactions. However, DBP adsorption on microplastics has not yet been closely examined. This work investigated the adsorption behavior of trihalomethanes (THMs)-a regulated and ubiquitous DBP class in chlorinated water-onto virgin and weathered polyvinyl chloride (PVC) microplastics, the most widely used plastic material in drinking water distribution and sewer systems. A comparative analysis of kinetic and isotherm test results indicated that the adsorption mechanisms mainly involved hydrophobic interactions from a combination of weak and strong physisorption behavior and possibly chemisorption. The adsorption coefficients from all the models examined suggested that the adsorption of THMs, and perhaps chemically similar DBPs, onto virgin PVC microplastics can be 10-20 µg g-1. However, the weathered PVC microplastics contained more polar functional groups, which led to a decreased hydrophobicity and reduced THM adsorption capacity by approximately 10%. These findings offer novel insights into the possible adsorption characteristics of disinfection byproducts (DBPs) onto microplastics and will assist in targeting more toxic DBPs for future investigations.

The aging of microplastics exacerbates the damage to photosynthetic performance and bioenergy production in microalgae (Chlorella pyrenoidosa)

The toxicity of microplastics (MPs) on freshwater plants has been widely studied, yet the influence of aged MPs remains largely unexplored. Herein, we investigated the influence of polyvinyl chloride (PVC) MPs, both before and after aging, at different environmentally relevant concentrations on Chlorella pyrenoidosa, a freshwater microalgae species widely recognized as a valuable biomass resource. During a 96-h period, both virgin and aged MPs hindered the growth of C. pyrenoidosa. The maximum growth inhibition rates were 32.40 % for virgin PVC at 250 mg/L and 44.72 % for aged PVC at 100 mg/L, respectively. Microalgae intracellular materials, i.e., protein and carbohydrate contents, consistently decreased after MP exposure, with more pronounced inhibition observed with aged PVC. Meanwhile, the MP aging significantly promoted the nitrogen uptake of C. pyrenoidosa, i.e., 1693.45 ± 42.29 mg/L (p < 0.01), contributing to the production of humic acid-like substances. Additionally, aged PVC induced lower chlorophyll a and Fv/Fm when compared to virgin PVC, suggesting a more serious inhibition of the photosynthesis process of microalgae. The toxicity of MPs to C. pyrenoidosa was strongly associated with intercellular oxidative stress levels. The results indicate that MP aging exacerbates the damage to photosynthetic performance and bioenergy production in microalgae, providing critical insights into the toxicity analysis of micro(nano)plastics on freshwater plants.

The carbon footprint of Bubble-PAPR™: A novel item of personal protective equipment.

Personal protective equipment has important environmental impacts, assessing these impacts is therefore an important element of personal protective equipment design. We applied carbon footprinting methodology to Bubble-PAPR™, a novel, part-reusable and part-recyclable powered air-purifying respirator, designed at our institution. Current guidance states that disposable respirator masks can be worn for 1-h in the United Kingdom, whilst the Bubble-PAPR™ allows prolonged use. Following a detailed use-case analysis, the carbon footprint of each component was estimated using a bottom-up (attributional) cradle-to-grave process-based analysis. Modelling considered the use of virgin or closed loop recycled polyvinyl chloride for the disposable hood element, and disposal via infectious or recycling waste streams to estimate a per-use carbon footprint. The per-use carbon footprint with manufacture from virgin polyvinyl chloride and disposal via incineration is 0.805 kgCO2e. With nine cycles of closed loop recycling and manufacture of the polyvinyl chloride hood (10 uses), the carbon footprint falls to an average of 0.570 kgCO2e per use. Carbon footprinting may contribute to the value proposition of this novel technology. We estimate that a single Bubble-PAPR™ use has a higher carbon footprint than disposable respirator mask-based PPE. However, this is mitigated in circumstances when multiple disposable mask changes are required (e.g. prolonged use) and use may be justifiable when user comfort, visualisation and communication with patients and colleagues are essential.

Study of Optical Properties of PVC/Ag2O Nano-Composites by Dispersing Spherical Nanofillers into Polymer Matrix under Normal and Heat Treated Conditions

In the present work a novel polymer/metal oxide composites containing Polyvinyl Chloride (PVC) and Ag2O nanoparticles (NP) were fabricated under room and elevated temperatures. The PVC/Ag2O NC has been fabricated to enhance the electronic application such as memory devices, sensors, electronic luminescent devices and medical applications. The Ag2O NP was synthesized by dropwise mixing process having 25 nm in size with spherical surface morphology. The Fourier transform infrared spectroscopy (FTIR) was taken for (1) virgin PVC film (2) PVC/Ag2O NC and PVC/Ag2O (heat treated) Composites. The formation of absorbance peaks, their shifting, intensity and maximum absorbance values were considered in all the three C C, C-Cl and C-H classified stretching modes of vibrations for different composites. It was found in C-C stretch range the virgin PVC back bone chain occurs at 1101 cm-1 which shifted to 1076 cm-1 for PVC/Ag2O NC, further shift is evident for PVC/Ag2O (heat treated) Composites at 1151 cm-1. In addition rocking vibration and wagging of methylene group changes in the same fashion. The change in spectral feature takes places due to filling of Ag2O NP in PVC matrix, indicates that changes in dipole moments occur as a result of molecular vibrations. It is also observed the absorbance peaks value is high for virgin PVC film for all modes of stretching vibration, which decreases for Ag2O/PVC (NC) further decrease is evident for Ag2O/PVC (NC) heat treated composite.

Unique metalloid uptake on microplastics: The interaction between boron and microplastics in aquatic environment

Boron pollution in the aquatic environment has a hazardous effect on human health and the ecosystem as a metalloid pollutant, and few researchers have focused on the potential interaction between boron and microplastics. We investigated the adsorption of boron on four types of microplastics (polyvinyl chloride (PVC), aged PVC, polystyrene (PS), and aged PS). The adsorption behavior was explored by kinetics, isotherm models, and several aqueous factors, including pH, humic acid, ionic strength (Na+), metal ion types (Mg2+, Ca2+, Cu2+, and Al3+), and the seawater environment. The adsorption capacities on microplastics were followed: aged PVC (0.91 mg/g) > aged PS (0.197 mg/g) > virgin PVC (0.1 mg/g) > virgin PS (0.005 mg/g). The adsorption kinetics and isotherm models suggested monolayer adsorption and chemisorption. Humic acid and high pH significantly inhibited the adsorption due to the complexation and hydrolysis of boric acid (B(OH)3), respectively. The presence of metal ions may enhance or hinder adsorption, depending on the boron species, ion concentration, ion type, and microplastics categories. The unique interaction mainly depended on surface complexations of B(OH)3 with oxygen-containing groups on microplastics surface. Because aged microplastics have more oxygen-containing groups, they can combine more B(OH)3, and PVC can adsorb more boron due to the CCl bond and surface diffusion. In the aquatic environment, however, metal ions may occupy these binding sites, and the electrostatic force between borate ([B(OH)4]−) and microplastics will take precedence. In the simulated intestines of warm-blooded animals, we achieved the greatest boron desorption ratio on microplastics. This work explored the adsorption characteristics of boron by microplastics and revealed potential environmental risks of metalloid enrichment.

Adsorption and Desorption Behaviors of Antibiotics on TWP and PVC Particles Before and After Aging

In recent years, microplastics (MPs), a new type of pollutant, have been widely dispersed in aquatic ecosystems. Compared with typical MPs (PVC, PP, PE, and PS), tire wear particles (TWP) exhibit significant differences in composition, additives, and characteristics. In this study, the adsorption and desorption of organic pollutants were compared between the typical MPs and TWP. With TWP and polyvinyl chloride (PVC) particles as adsorbents, oxytetracycline (OTC) and sulfamethoxazole (SMZ) as adsorbates, the adsorption and desorption of organic pollutants by TWP and PVC particles before and after aging were studied. Correctly understanding the behavior of MPs in an aquatic environment is of great significance. The results indicated that during the UV aging process, both TWP and PVC exhibited cracks, pits, and bulges on the particle surface, increased specific surface areas, increased strength of oxygen-containing functional groups, and enhanced hydrophilicity. The adsorption modes of TWP and PVC before and after aging were in two stages:surface adsorption and liquid film diffusion. TWP has a better fit for the Freundlich model, belonging to multi-layer adsorption, while PVC has a better fit for the Langmuir model, belonging to monolayer adsorption. The carrier effect of TWP on antibiotics was better than that of PVC, with the adsorption capacity of OTC on virgin TWP and PVC reaching 5.14 mg·g-1 and 1.38 mg·g-1, respectively. Additionally, the adsorption capacity of OTC on the aged TWP and PVC reached 5.82 mg·g-1 and 2.13 mg·g-1, respectively, which was better than with the virgin samples. The desorption capacity of aged TWP and PVC for antibiotics was better than the virgin materials, while the desorption rate was lower. In the same desorption solution, the desorption effect of TWP on antibiotics before and after ageing was better than that of PVC. The desorption effect of TWP and PVC on antibiotics in a simulated intestinal fluid environment was significantly better than that in an ultra-pure water environment.

Experimental investigation of a tribo-electrostatic separation device using linear moving electrodes

The aim of this paper is to carry out an experimental analysis of a triboelectrostatic separation device constituted of two “back-and-forth” moving horizontal plate electrodes supplied by two high-voltage DC supplies of opposite polarities. The experiments were performed using samples of micronized white pure virgin PolyVinyl Chloride particles (WPVC) and gray PolyVinyl Chloride particles (GPVC) of average size 100 µm. Moreover, a homemade method was developed to estimate the purity of the separated products. It was deduced that the separation outcome, in terms of recovery and purity, is efficient and depends on several factors: the high-voltage level, the movement speed of the electrodes, the fluidization rate and the composition ratio of the granular mixture.

Effects of interface modification on composites based on olive husk flour

Every year a considerable amount of olive husk was rejected in nature by different oil mills or incinerated. The valorization of these agricultural wastes by its incorporation as loading in the development of composite materials with polyvinyl chloride (PVC) is the object of this research. To improve the properties of the interface between the polymer matrix and olive husk flour (OHF), two chemical treatment methods were conducted. The first treatment consisted to use PVC-g-MA (maleic anhydride grafted on PVC) as a compatibilizer in composites; the second was a surface modification of olive husk flour by benzoylation. In this context, we prepared various formulations based on polyvinyl chloride/olive husk flour with different loading rates (10, 20, and 30%) using twin-screw extrusion. The Fourier transform infrared was used to study the chemical modification of the fiber. The composites were characterized by mechanical tests, thermogravimetric (ATG/DTG), mechanical dynamic analysis (DMA), and the physical characterization by the water absorption test. The thermogravimetric analysis revealed the improvement of the thermal stability of the composites with and without treatment compared to virgin PVC.

Modeling constituent–property relationship of polyvinylchloride composites by neural networks

AbstractThe purpose of this study is to develop an artificial neural network (ANN) model to predict and analyze the relationship between properties and process parameters of polyvinyl chloride (PVC) composites. The tensile strength, ductility, and density of PVC are modeled as a function of virgin PVC, recycled PVC, CaCO3, di‐2‐ethylhexyl phthalate, chlorinated paraffin wax, and CaCO3 particle size. The ANN model is trained using the backpropagation algorithm. The developed model was validated with a set of unseen test data. The correlation coefficient adj. R2 values for test data were 0.95, 0.83, and 0.90 for tensile strength, density, and ductility, respectively. The relationship between constituents and properties of PVC composites were analyzed by sensitivity analysis, index of relative importance, and quantitative estimation. The study concluded that ANN modeling was a dependable tool for the optimization of constituents for the desired properties of PVCs.

Textural, surface and chemical properties of polyvinyl chloride particles degraded in a simulated environment

Virgin polyvinyl chloride (PVC) particles were exposed to heat, ultraviolet B (UVB) and solar radiation either in artificial seawater or in air for different periods of time. The surface and chemical properties of fresh and degraded particle surfaces were determined via image analysis using scanning electron micrographs, a Brunauer-Emmett-Teller (BET) specific surface area analyzer and infrared spectroscopy. Thermal and UVB degradation resulted in unique PVC morphologies. In addition, the increased presences of functional groups were evident as dehydrochlorination and oxidation during the degradation process, which altered the chemical properties of PVC. In contrast, under solar exposure with or without seawater, unevenness to the surface was noted that seems to originate from degradation of the PVC surface; in addition, no new functional groups were found. This suggests that the chemical properties of PVC are stable over extended periods in the marine environment.

Artificial neural network modeling to evaluate polyvinylchloride composites’ properties

The mechanical properties of extruded Polyvinylchloride (PVC) composites cannot be easily predicted due to the nonlinear nature of the relationship between the composite’s composition and the resulting after-production properties. In the work presented herein, supervised artificial neural network (ANN) modeling is used to predict and optimize three properties (tensile strength, ductility and density) of PVC composites having different weight percentages of virgin PVC, CaCO3, plasticizers, and recycled PVC. Different ANN models, designed and analyzed through factorial design and analysis of variance methodology, were evaluated using an experimental dataset which was designed according to the mixture design of experiments approach. The results show that the constituents-mechanical properties relationship of PVC composites’ can be accurately estimated using several ANN models including Levenberg-Marquardt/6-[18-9]3-3/Radial basis and Levenberg-Marquardt/6-[9-18]3-3/Log sigmoid models. The results also show that the ANN modeling is capable of determining the optimal weight percentages of the different PVC composite constituents in order to achieve a required composite property.

Cost-effective and sustainable approach to transform end-of-life vinyl banner to value added product

Australian industry estimates 500 t of banners are land-filled every year due to its complex nature which makes recycling either difficult or an expensive process. This study details a new low-cost solution for waste Polyvinyl Chloride (PVC) coated banners that does not require the separation of the PVC from the polyester fabric; overcoming a major barrier to recycling. End-of-life banner material was shredded with recycled cable material which improved the mix density and made material suitable for plastic manufacturing techniques. Life cycle analysis study proves that replacing virgin PVC by recycled PVC from banner emits 78% less kg CO2 equivalent. Both materials were characterized elementally and structurally using X-ray fluorescence and X-ray diffraction techniques. A safe fabrication temperature (<200 °C) was determined using thermogravimetric analysis coupled with furrier transform infra-red spectroscope to prevent the generation of toxic gases. Composite panels were fabricated using hot press with various wt. % of banner and cable material. Panels were tested physically and mechanically and their performance in various possible environments was observed. Inductive Couple Plasma Mass Spectroscope also demonstrated no toxic elements were released from the panels after soaking in distilled water for 28 days. These results demonstrate that waste PVC-coated banners can be used to fabricate strong and durable composite panels for multiple indoor and outdoor applications and one example of final product is shown. Suggested use of waste PVC through this cost-effective and sustainable approach can stop 220–250 t of waste going to landfill every year in Australia.

Electrical and Tensile Properties of Carbon Black Reinforced Polyvinyl Chloride Conductive Composites

Conductive polymer composites are becoming more important and useful in many electrical applications. This paper reports on the carbon black (CB) reinforced polyvinyl chloride (PVC) conductive composites. Conductive filler CB was reinforced with thermoplastic PVC by compression molding technique to make conductive composites. The particle size of CB was measured, as it affects the electrical conductivity of the composites. Different types of CB-PVC compression-molded composites were prepared, using CB contents from 5 to 30 wt %. The electrical and tensile properties of these composites were studied and compared. Improved electrical properties were obtained for all CB-PVC conductive polymer composites compared to virgin PVC composite. However, the tensile properties of the CB-PVC composites increased up to 15 wt % CB loading, and then decreased, and elongation at break decreased with increasing CB loading. The structure of the CB, PVC and CB-PVC composites were studied by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopic analysis. ATR-FTIR spectra provide evidence of the formation of CB-PVC composites. The microstructural analyses showed a good dispersion of CB in PVC matrix.

Study of various thermal responses of PVC – CPVC Blends

Binary blends of Polyvinyl Chloride (PVC) / Chlorinated Polyvinyl Chloride (CPVC) were prepared using Haake Polylab extruder. The blends were then compression molded and their thermal properties were evaluated and compared. 7 different batches including virgin PVC and CPVC were prepared with varying PVC compositions from 10 to 90%. DMA results showed the immiscibility of blends above a certain composition. Colorimetry results give an insight into Yellowness index values of various blends with different compositions. Similarly, other improvements and optimization was observed and recorded for different batches while studying their thermal properties.

Effects of nanoclay on physical and mechanical properties of wood-plastic composites

ABSTRACTEffects of nanoclay (NC) on physical and mechanical properties of wood-plastic composite (WPC) were studied here. Virgin, recycled, and mixed (50/50% of virgin/recycled) polyvinyl chloride (PVC) were used as the matrix in the WPC. Specimens with three NC contents of 1.5%, 3%, and 5% were manufactured; they were then compared with control specimens. Totally, 12 treatments were manufactured. The physical and mechanical properties were measured in accordance with the ASTM standards. The highest properties were found in specimens made from virgin PVC. Addition of recycled PVC resulted in significant decrease in all properties. NC improved all physical and mechanical properties studied in the present research project; the highest properties were observed in specimens with 5% of NC content. The improvement in properties was as a result of formation of bonds between the hydroxyl groups of NC with the wood flour components. It was concluded that NC would significantly improve the properties in all the three PVC types of virgin, recycled, and mixed. From an industrial point of view, it was concluded that mixing virgin and recycled PVC can be recommended not only to decrease production costs, but also to partially solve the problem of PVC residue which are not bio-degradable.

Production of nano zinc borate (4ZnO·B2O3·H2O) and its effect on PVC

Abstract In this study, nano sized zinc borate powder with a formula of 4ZnO·B2O3·H2O was synthesized using 2ZnO·3B2O3·3.0–3.5H2O as a starting chemical which was produced using a wet chemical method. After dissolving 2ZnO·3B2O3·3.0–3.5H2O in an ammonia solution, the clear solution was boiled until a white powder formed. The resultant powder was characterized with XRD, FTIR, TGA and TEM. XRD, FTIR and TGA results proved that the powder was belonged to the 4ZnO·B2O3·H2O. Nano composites of 4ZnO·B2O3·H2O–polyvinylchloride (PVC) were produced by injection moulding by adding 1 and 5 wt% zinc borate powders into PVC to enhance its flame retardancy. Limiting oxygen index (LOI) of virgin PVC increased from 41% to 47% and 54% for the 1 and 5 wt% zinc borate added PVC, respectively. Nano zinc borate addition into the PVC does not have considerable negative effect on the mechanical properties of zinc borate–PVC composites even at high amounts of 5 wt%.

Construction and demolition waste as a source of PVC for recycling

Construction and demolition waste can contain considerable amounts of polyvinyl chloride (PVC). This paper describes a study of the recycling of PVC pipes collected from such waste materials. In a sorting facility for the specific disposal of construction and demolition waste, PVC was found to represent one-third of the plastics separated by workers. Pipes were sorted carefully to preclude any possible contamination by poly(ethylene terephthalate) (PET) found in the waste. The material was ground into two distinct particle sizes (final mesh of 12.7 and 8 mm), washed, dried and recycled. The average formulation of the pipes was determined based on ash content tests and used in the fabrication of a similar compound made mainly of virgin PVC. Samples of recycled pipes and of compound based on virgin material were subjected to tensile and impact tests and provided very similar results. These results are a good indication of the application potential of the recycled material and of the fact that longer grinding to obtain finer particles is not necessarily beneficial.

Impact Response of Bamboo-Plastic Composites with the Properties of Bamboo and Polyvinylchloride (PVC)

This paper investigates the impacts of moisture content, granular size of bamboo particles and the proportion between bamboo and Polyvinyl Chloride (PVC) on the stability and mechanical properties of bamboo-plastic composites, which were made using virgin PVC with bamboo granule as filler. Composite panels which were made with higher moisture content of bamboo through hot-press moulding exhibited excellent dimensional stability. The tensile and flexural properties of the composites were optimal at 40 mesh granule size of bamboo. Dimensional stability and strength properties of the composites can be improved by increasing the polymer content.

Study of the natural ageing of PVC insulation for electrical cables

The characterisation of high voltage cable insulation waste is addressed in an effort to determine their further utilisation either as feed in reprocessing or for the recovery of the energy and material content by pyrolysis. Electrically aged (18 years outdoors at 6–10 kV) polyvinyl chloride (PVC) cables were ground by mechanical or cryogenic procedures. The waste was studied in comparison with a PVC virgin resin and a PVC virgin formulation similar to that of the cables both in quantities of additives and structure of polymer. After successive extractions in acetone and benzene the base polymer and extracts were analysed by elemental analysis, GPC, viscometry, IR and 1H-NMR spectroscopy, TG, DSC, and several standard methods of plastic analysis (plasticizer absorption, static thermal stability, etc.). From the acetone extracted quantities and the plasticizer absorption measurements it appears that only 1–2% di-2-ethylhexylphthalate (DOP) was lost during the service-life of cables and most of the initial quantity remained in the cable composition so only a small addition is necessary for the reprocessing. The IR spectra of polymer extracted from electrical cable waste exhibit important changes concerning double bonds and carbonyl groups. The T g value is higher for the waste material indicating that it was rigidized due to the polyene fragments arising from partial dehydrochlorination. This is also supported by the viscometric and GPC measurements, the PVC from waste having a higher molecular weight than virgin PVC. Based on T g curves and static thermal stability the following order of thermal stability has been established: PVC waste jacket<PVC electrical cable waste<virgin PVC<PVC virgin cable formulation. One can conclude that PVC cable wastes have retained most of the characteristics required for reprocessing, but a higher level of stabilisers must be used to ensure the stabilisation of the deteriorated structure and compensate partial deactivation of the initial stabiliser system.