Base Polymer Research Articles

Flexible PMN-PT/rGO/PVDF-TrFE based composites for triboelectric and piezoelectric energy harvesting

Flexible piezoelectric nanogenerator (PENG) and triboelectric nanogenerators (TENG) have gained prodigious attention due to the increasing demand of nano and micro energy for driving of miniaturized electronic devices, sensors, and various internet of things. The key challenges that are currently in focus are material selection and simple fabrication techniques for improved electrical performance along with good mechanical properties and flexibility. Herein, a ferroelectric polymer, poly(vinylidenefluoride-co-trifluoroethyne) (PVDF-TrFE), is chosen as a flexible material due to its promising prospect for energy harvesting. To improve the performance, a ceramic material, 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (PMN-PT), with very high piezoelectric properties has been selected as the reinforcement. Further, reduced graphene oxide has been added as a conducting filler to promote charge conduction. A remarkable enhancement in output voltage of nearly 3 fold is achieved in PVDF-TrFE/PMN-PT (PP) polymer composite as compared to the base polymer PVDF-TrFE (P) TENG device. Furthermore, the PVDF-TrFE/rGO/PMN-PT (PPR) as a PENG illustrates a great improvement in output current of the order of 2 as compared to the pristine polymer. The maximum output voltage as shown by the TENG is 200 V and the maximum current that is shown by the PENG is 30 µA. Therefore, the fabricated PMN-PT based PVDF-TrFE nanogenerators have an immense prospect for applications in self-powered systems.

Removal of Hg(II) with MgAl-layered double hydroxide functionalized by schiff base ligands: Application and condition optimization

To effectively remove heavy metal Hg(II) from water bodies, a novel adsorbent of MgAl-layered double hydroxide (LDH) was designed and functionalized with Schiff base. The characterization results of the adsorbent (MgAl-LDH@SiO2-AG) show that the Schiff base polymer was successfully coated onto the outside surface of MgAl-LDH with hexagonal structure. The theoretical maximum adsorption capacity to Hg(II) is 228.46 mg/g at pH 7 and 298 K. The different pH solutions were investigated from pH 2 to 8, and the optimal capacity of MgAl-LDH@SiO2-AG toward Hg(II) achieves 268.7 mg/g at pH = 7.2, T = 36.8 °C, C0 = 32.1 mg/L and dosage = 0.083 g/L. In reality, the adsorbent not only exhibits efficient removal of Hg(II) in various water bodies, including lake water, river water, effluent from sewage treatment plant, but also has an excellent selectivity in electroplating wastewater containing different heavy metal ions. Low contents of TN and TP in real wastewater have less effect on the removal of Hg(II). Moreover, the prepared adsorbent had a good reusability and stability. The reaction mechanism mainly involves chelation with nitrogen/oxygen-containing groups and the predominant participation of nitrogen atoms in the Schiff base functional group. The removal of Hg(II) relies on the pseudo-second-order kinetics and Langmuir model, and is an endothermic and spontaneous chemical reaction. The present work offers a practical method for preparing highly effective adsorptive materials with the LDH composites and for the treatment of heavy metal Hg(II) from water bodies.

Exploration of polymer inclusion membrane for nickel recovery from waste printed circuit boards

In this study, the selective recovery of nickel ions from waste printed circuit boards (WPCBs) solution through polymer inclusion membranes (PIMs) containing 5-nonylsalicylaldoxime (ACORGA M5640) as extracting agent and polyvinyl chloride (PVC) as base polymer has been explored. The proposed method utilizes combined process of solvent extraction and PIMs route for the recovery of nickel. As a first step, the copper was solvent extracted using ACORGA M5640 by the previously developed method by our group and further the raffinate of first stage is utilized as feed phase for the nickel recovery. The consequence of carrier concentration on transportation of nickel, pH of feed solution and effect of acidity of stripping agent has also been investigated. The increase in carrier concentration increases the nickel removal efficiency from feed phase to strip phase. Moreover, the increase in concentration of strip phase also increases the nickel ion flux. 99.77 % nickel was selectively recovered from leach liquor using PIMs containing 50 % of ACORGA M5640. Further, PIMs stability and transport studies has been carried out to know the feasibility of its use in recycling of electronic waste.

New Framework for studying High Temperature Tribology (HTT) Using a Coupling Between Experimental Design and Machine Learning

High temperature tribology (HTT) is considered to start at a minimum temperature of 300°C, where organic base oils and polymers begin to decompose, up to a temperature of 1200°C. In this area of application, a tribological test is typically performed under dry or solid friction, unless a solid lubricant is used, as most lubricants oxidize or decompose when exposed to these extreme temperatures. This is the case of hot forming tribology. Therefore, specific tribometers have been developed to study the tribological behavior, wear modes, friction-wear mechanisms, and other tribological aspects in the case of contact workpiece-forming tools. However, as the interdisciplinary character of tribology represents great opportunities, but also a huge challenge to well study the tribological behaviour of materials and systems, particularly at hot temperature, results are well impacted by the proposed hypothesis, the limited number of parameters to study, the dynamic behaviors of solicitations, etc. A new approach to overcoming its limitations remains a necessity in modern research. After giving general definitions of the notions of tribological system and tribometer, an assessment of the different configurations of these test benches is established. The presentation of the tribometers is organized according to the configuration adopted. The study is based on the identification of the “originality” of the benches and the limitations of the approaches used in the study of hot temperature sliding contact. The framework of the coupling between experimentation and machine learning is presented. Different scenarios are discussed in order to develop new approaches/methods of collaboration between the design of experiment, numerical development, and ML algorithms.

High‐Toughness Hydrated Polymer Electrolytes for Advanced Structural Supercapacitors

AbstractStructural supercapacitors that simultaneously bear mechanical loads and store electrical energy have exciting potential for enhancing the efficiency of various mobile systems. However, a significant hurdle in developing practical structural supercapacitors is the inherent trade‐off between their mechanical properties and electrochemical capabilities, particularly within their electrolytes. This study demonstrates a tough polymer electrolyte with enhanced multifunctionality made through the controlled hydration of a solid polymer electrolyte with poly(lactic acid) (PLA) and lithium salts. Characterization via differential scanning calorimetry, X‐ray diffraction, and Fourier transform infrared spectroscopy confirms the consistent amorphous solid solution phase in varying salt concentrations, whether dried or hydrated. Electrochemical tests and tensile tests are performed to evaluate the ionic conductivity and mechanical properties of these electrolytes. The results indicate that the strategic incorporation of water in the polymer electrolyte significantly enhances the ionic conductivity while preserving its mechanical properties. A specific composition demonstrated a remarkable increase in ionic conductivity (3.11 µS cm−1) coupled with superior toughness (15.4 MJ m−3), significantly surpassing the base polymer. These findings open new horizons for integrating electrochemical functionality into structural polymers without compromising their mechanical properties. Additionally, the paper reports the successful fabrication and testing of structural supercapacitor prototypes combining carbon fibers with fabricated electrolytes, showcasing their potential for diverse applications.

Effect of Plasticizer Type on Polymer Inclusion Membranes Properties and Performance for Zinc Separation

AbstractThe goal of the present study is to evaluate the effect of plasticizer in PIMs properties and performance for zinc separation. Membranes were prepared by casting a solution containing poly (vinyl chloride) (PVC) as base polymer, di (2‐ethylhexyl) phosphoric acid (D2EHPA) as carrier, and 2‐nitrophenyl octyl ether (NPOE) or tris (2‐butoxyethyl) phosphate (TBEP) as plasticizers. The newly developed PIMs transported practically all ZnII ions from a feed phase at pH 5 to a 1 M H2SO4 stripping phase. The results showed that the transport flux and its efficiency depend on the chemical nature of the plasticizer. It can be perceived that NPOE (with dielectric constant of 23.1) produced the highest transport flux of zinc (J0=1.62±0.05 10−5 mol m−2 s−1). The single ion transport of zinc was significantly higher than the binary and ternary mixtures. In ternary solution, the transport efficiency for metal ions was in the order of ZnII>CuII>NiII. The transport efficiency of the PVC/NPOE/D2EHPA membrane remained constant until the seventh use. The findings of this work will allow the invention of advanced separation technology ensuring the sustainability of metal resources.

Modelling of Static and Dynamic Elastomer Friction in Dry Conditions

Understanding the tribological behavior of elastomers in dry conditions is essential for sealing applications, as dry contact may occur even in lubricated conditions due to local dewetting. In recent decades, Persson and co-authors have developed a comprehensive theory for rubber contact mechanics and dry friction. In this work, their model is implemented and extended, particularly by including static friction based on the bond population model by Juvekar and coworkers. Validation experiments are performed using a tribometer over a wide range of materials, temperatures and speeds. It is shown that the friction model presented in this work can predict the static and dynamic dry friction of various commercial rubber materials with different base polymers (FKM, EPDM and NBR) with an average accuracy of 10%. The model is then used to study the relevance of different elastomer friction contributions under various operating conditions and for different roughness of the counter surface. The present model will help in the development of novel optimized sealing solutions and provide a foundation for future modeling of lubricated elastomer friction.

Adsorption and transport of acid dye through polymer inclusion membrane with Aliquat 336 and TBP

Colour is typically the initial pollutant identified in wastewater. Membrane separation represents a novel approach to separation processes, with expectations of supplanting many traditional separation systems. The aim of this study is to investigate polymer inclusion membranes (PIMs) consisting of tri octyl methyl ammonium chloride as the carrier, tributylphosphate as the modifier, poly-vinyl chloride as the base polymer and 2-Nitro phenyl pentyl ether as the plasticizer for removing an acid dye (Red Erionyl A-3G) from aqueous solution. The dye adsorption on the membrane surface and its transition to the stripping phase was achieved by placing the membrane between two glass cells. Changing the stripping solution ensured both adsorption on the membrane surface and the transfer of all the dye to the stripping stage. Using a mixture of 0.8 M salicylic acid and 0.8 M NaOH, along with stirring at 1000 rpm during the stripping phase, extraction efficiency reached 98% in the feed phase and 53% in the stripping phase. When 1 M NaOH solution was employed as the stripping solution, the membrane absorbed all the dye within 10 minutes, but there was no transition to the stripping phase. The membrane has a durability of 2 days.Graphical abstract

Influence of biodegradable polymer films on conformation of polydiacetylene–silver nanocomposites as colorimetric time–temperature indicators

Time–temperature indicators (TTIs) are used to monitor the quality of packaged products by providing a visual indication of product deterioration due to time and temperature during transportation, storage, and distribution. This study aimed to investigate the effect of biodegradable polymer films on the limits of the color change mechanism in polydiacetylene. TTIs were prepared using biodegradable polymer films based on carboxymethyl cellulose, polyvinyl alcohol (PVOH), chitosan, and carboxymethyl chitosan (CMCh) with thermochromic properties provided by silver nanoparticles–polydiacetylene (10 % w/w AgNP–PDA). Vesicle and core–shell structures of AgNP–PDA appeared in the chitosan- and PVOH-based films owing to the effects of functional groups in the base polymer. Total color difference measurements indicated that the AgNP–PDA-containing films exhibited color changes in response to storage at 35 ℃ for a total of 14 days. Specifically, the AgNP–PDA in the chitosan- and PVOH-based films produced noticeable color changes from blue to reddish-purple or reddish-brown, respectively, which was influenced by the core–shell structure of AgNP–PDA embedded in the base polymer. The developed films are very promising for applications as TTI devices for tracking fresh products, supported by the compatibility of activation energy (Ea) from 29 to 79 kJ/mol.

Mechanics of dissolving microneedles insertion into the skin: Finite element and experimental analyses

AbstractTransdermal drug delivery using dissolving microneedles (DMNs) is promising due to increased patient compliance and safety. This article presents a comprehensive simulation and experimental analysis of DMNs with varying tip and base diameters and polymers. The objective of the simulation study is to identify the optimal tip and base diameter of DMNs, as well as the most suitable polymer, for achieving maximum penetration depth. The simulation results showed that the compound consisting of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) in a ratio of 2:1, with a tip radius of 17.5 μm and a base radius of 150 μm, achieved the deepest penetration among the different types of polymers investigated (including PVA, hyaluronic acid (HA), and PVA/PVP in ratios of 1:1 and 1:2). In addition, mechanical and skin penetration experiments were performed on PVA/PVP 2:1 DMNs with varying concentrations of 4, 7, 10, and 15% w/w to determine the optimal polymer concentration. The results of this study indicated that the optimal composition, considering the viscosity of the polymer solution and the simplicity of filling the silicone negative molds, is a PVA/PVP 2:1 with a concentration of 7% w/w.

Sulphonated graphene oxide as functionalized filler for polymer electrolyte membrane with enhanced anti-biofouling in microbial fuel cells

This research focuses on the development of a polymer electrolyte membrane (PEM) which is intended to increase power generation while addressing the persistent issue of biofouling in microbial fuel cells (MFC). The central hypothesis of this research work is that a novel PEM made from sulphonated polyether ether ketone (SPEEK) grafted with styrene sulphonic acid (SSA) integrated with sulphonated graphene oxide (SGO) will improve the membrane properties as well as enhance the anti-biofouling effect. The optimal percentage of SSA grafting has been determined based on physicochemical properties of the membrane. Various weight percentages of SGO (2.5, 5, 7.5, & 10 wt%) were introduced to the SPEEK/SSA base polymer to augment the physicochemical properties and also to defend against biofouling. Among the tested membranes, the SPEEK/SSA+5 % SGO composite membrane demonstrates the highest water uptake (106.2±1.9 %) and ion exchange capacity (1.55±0.2 meq g−1). Due to these superior properties, it achieves the maximum power density of 203 mW m−2 and an open circuit voltage (OCV) surpassing 700 mV. The crystal violet assay performed post-MFC operation affirms that the nanocomposite membrane effectively inhibits bacterial fouling. This study positions itself as a solution for long-term, high-performance MFC operations, all while significantly increasing power output and reducing biofouling concerns.

An Innovative Approach to Assessing the Quality of Organoleptic Properties of Base Polymers in Orthopedic Dentistry

Modern technologies using an «electronic nose» imitating the human sense of smell open up new prospects for the objective assessment of the organoleptic properties of polymer materials. The purpose of the study was to compare the level of emissions of volatile organic compounds from modern base materials used in various technological processes for the manufacture of removable denture structures, as well as to assess the possible organoleptic properties of the finished dentures in comparison with known analogues using an «electronic nose» gas analyzer. For this purpose, samples were made from different polymer base materials in the amount of 26 pieces, which were studied using an “electronic nose” gas analyzer using the author’s method [Kuchmenko et al., 2023]. The study confirmed the effectiveness of the proposed improved technology in reducing the noise level of volatile organic compounds in samples made from the «Belakril-E GO» base material by 29 % compared to similar samples produced using standard technology. A reduction in the amount of volatile organic compounds that can cause unwanted odors confirms the higher purity and quality of the polymer and will contribute to a more comfortable adaptation of patients to removable dentures made from this polymer.

Fabrication, Evaluation and In-vitro, In-vivo Efficacy of Electrospun Nanofiber Mats of Tinospora cordifolia Extract and Curcumin

The current research work highlights the fabrication and evaluation of nanofiber mats prepared using electrospinning technology containing Tinospora cordifolia extract and curcumin incorporated in chitosan polymer. The study of the prepared mats was carried out to optimize the formulations, to check in-vitro antibacterial activity, and to establish the effectiveness in diabetic wound healing by conducting an animal study. The nanofiber mats of curcumin and leaf extract of T. cordifolia using chitosan as a base polymer were prepared, optimized, and evaluated for antibacterial activity in-vitro, while their ability to enhance the wound healing process was checked using an animal model. The research parameters included the rate at which the wound contracted besides the time taken for epithelialization by using the wound healing model- excision technique. The results we found are encouraging for further studies. The nanofibers showed good antibacterial potential and faster healing of wounds. The research finished by developing an improved new formulation that effectively combats bacterial resistance, a common problem in the diabetic wound healing process. The mixture will not only fight resistant bacteria, but it will also help diabetic wounds heal faster because the T. cordifolia leaf extract is known to improve blood vessel growth and tissue remodeling.

Formulation and Evaluation of Electrospun Nanofiber Mats of Curcumin and Leaf Extract of Tinospora cordifolia: Designed for Accelerating Diabetic Wound Healing

Traditional herbs like Tinospora cordifolia and curcumin have many therapeutic benefits. However, curcumin’s limited bioavailability is a problem. Electrospun nanofibers are an answer because they increase the effective surface area greatly, and make drug delivery better in almost all aspects. The combination in the form of nanofibers can be greatly useful in the treatment of diabetic wound healing, where curcumin, the known antibacterial and anti-inflammatory element, plays an important role. It is observed that when combined with extract of leaves of T. cordifolia, which has known antidiabetic and wound healing actions, blended in the chitosan polymer, which is itself a weak antibacterial compound hence can be one of the solutions to the menace of bacterial resistance which is very common in diabetic wound healing. This research aims to create and test electrospun nanofiber mats of curcumin and T. cordifolia leaves extract blended in chitosan as a base polymer in the treatment of diabetic wound healing. Leaves of the plant T. cordifolia, which were collected from the institute’s botanical garden, were subjected to drying and then prone to solvent extraction using methanol and acetone, resulting in the production of bioactive extracts. The curcumin was obtained as a gift sample from Sanjay Chemicals, Mumbai. Nanofibers were electrospun from chitosan, T. cordifolia leaf extract and curcumin. Characterization included scanning electron microscope (SEM), water contact angle measurement, TGA/DSC analysis, drug release studies, fourier-transform infrared (FTIR) analysis, swelling tests and in-vitro release profiling. The nanofiber mats of curcumin and leaves extract of T. cordifolia using chitosan as a base polymer were prepared and evaluated at various parameters. The results we found are very promising. The nanofibers formed by using electrospinning techniques show good content uniformity as well as good diameter which was checked using SEM. The study confirmed no component interactions using differential scanning calorimetry (DSC). The good hydrophilicity of mats was found to ensure good retention time. The study concluded with the formation of a novel formulation that can fight the menace of bacterial resistance, which is very common in the diabetic wound healing process. The formulation will ensure not only countering bacterial resistance but also the faster healing of diabetic wounds, as T. cordifolia leaves extract is known to improve angiogenesis and tissue remodeling.

The Study of Composite Materials Properties Based on Polymers and Nano-Additives from Industrial Wastes from Kazakhstan.

This research is aimed at studying the properties of polymer anticorrosion coatings based on ED-20 resin widely used in practice and industrial wastes. In this work, three basic types of nanoscale nanofillers were chosen: dispersed particles-microsilica, microspheres obtained at Kazakh enterprises, and carbon nanotubes. Physicochemical research methods were used in the research: a laser analyzer for studying the dispersibility of industrial waste and spectrometric research methods. The properties of materials were investigated by standardized methods. The obtained results show that the introduction of microsilica and microspheres obtained at Kazakhstani enterprises, used as additives, improves both the physical and mechanical properties of epoxy composites compared to the standard (control) material. The results of experiments have shown that the optimal content of additives of microsilica and microspheres provides an improvement in the physical and mechanical properties of epoxy composites in comparison with the standard (control) material. Studies have shown that the introduction of microspheres into ED-20 polymer increases impact toughness. The introduction of microsilica into the matrix contributes to the increase of elastic modulus. Experimental studies of optical properties of samples of carbon composite polymer films based on polystyrene (PS) with additives of carbon nanotubes C60 and C70 and multilayer carbon nanotubes were also carried out. The experimental results obtained for the optical properties of polymer composites based on basic polymers from solid waste and carbon nanotubes showed that the optical properties of polymer composites undergo noticeable changes.

Kinetics of Nitrite Adsorption onto a Styrene Divinylbenzene Macroporous Strong Base Polymer

A suitable adsorbent for the treatment of nitrite in wastewater was investigated using a macroporous styrene divinylbenzene strong base polymer for 10−3 M to 6 x 10−3M NaNO2 at room temperature using a batch protocol. The supernatant concentrations were determined rapidly and inexpensively by an electrochemical method. To investigate the sorption mechanism and the rate-determining step, four kinetic models were investigated. The pseudo-second order kinetic model best fit the nitrite adsorption onto the polymer. The highest correlation coefficient (0.9999) and chi square (7.59 x 10−4) values were obtained for 0.046 to 0.276 g L−1 NO2 - which is characteristic of chemosorption. The results demonstrate that the investigated polymer is suitable at room temperature for removing nitrites for water to the legally allowed values for 10−3 M to 1.5 x 10−3 M NaNO2 but dilution is required for higher concentrations.

Utilization of Spent Coffee Grounds as a Food By-Product to Produce Edible Films Based on κ-Carrageenan with Biodegradable and Active Properties.

Coffee ranks as the second most consumed beverage globally, and its popularity is associated with the growing accumulation of spent coffee grounds (SCG), a by-product that, if not managed properly, constitutes a serious ecological problem. Analyses of SCG have repeatedly shown that they are a source of substances with antioxidant and antimicrobial properties. In this study, we assessed SCG as a substrate for the production of edible/biodegradable films. The κ-carrageenan was utilized as a base polymer and the emulsified SCG oil as a filler. The oil pressed from a blend of Robusta and Arabica coffee had the best quality and the highest antioxidant properties; therefore, it was used for film production. The film-forming solution was prepared by dissolving κ-carrageenan in distilled water at 50 °C, adding the emulsified SCG oil, and homogenizing. This solution was cast onto Petri dishes and dried at room temperature. Chemical characterization showed that SCG increased the level of polyphenols in the films and the antioxidant properties, according to the CUPRAC assay (CC1 23.90 ± 1.23 µmol/g). SCG performed as a good plasticizer for κ-carrageenan and enhanced the elongation at the break of the films, compared with the control samples. The solubility of all SCG films reached 100%, indicating their biodegradability and edibility. Our results support the application of SCG as an active and easily accessible compound for the food packaging industry.

Post-processing of a 3D-printed denture base polymer: Impact of a centrifugation method on the surface characteristics, flexural properties, and cytotoxicity

ObjectivesTo investigate the impact of a centrifugation method on the surface characteristics, flexural properties, and cytotoxicity of an additively manufactured denture base polymer. MethodsThe tested specimens were prepared by digital light processing (DLP). A centrifugation method (CENT) was used to remove the residual uncured resin. In addition, the specimens were post-processed with different post-rinsing solutions: isopropanol (IPA), ethanol (EtOH), and tripropylene glycol monomethyl ether (TPM), respectively. A commercial heat-polymerized polymethyl methacrylate was used as a reference (REF). First, the values of surface topography, arithmetical mean height (Sa), and root mean square height (Sq) were measured. Next, flexural strength (FS) and modulus were evaluated. Finally, cytotoxicity was assessed using an extract test. The data were statistically analyzed using a one-way analysis of variance, followed by Tukey's multiple comparison test for post-hoc analysis. ResultsThe Sa value in the CENT group was lower than in the IPA, EtOH, TPM, and REF groups (p < 0.001). Moreover, the CENT group had lower Sq values than other groups (p < 0.001). The centrifugation method showed a higher FS value (80.92 ± 8.65 MPa) than the EtOH (61.71 ± 12.25 MPa, p < 0.001) and TPM (67.01 ± 9.751 MPa, p = 0.027), while affecting IPA (72.26 ± 8.80 MPa, p = 0.268) and REF (71.39 ± 10.44 MPa, p = 0.231). Also, the centrifugation method showed no evident cytotoxic effects. ConclusionsThe surfaces treated with a centrifugation method were relatively smooth. Simultaneously, the flexural strength of denture base polymers was enhanced through centrifugation. Finally, no evident cytotoxic effects could be observed from different post-processing procedures. Clinical significanceThe centrifugation method could optimize surface quality and flexural strength of DLP-printed denture base polymers without compromising cytocompatibility, offering an alternative to conventional rinsing post-processing.

Radiation grafted polyacrylic acid–polyurethane foam copolymer for efficient toxic metal removal from aqueous waste: a sustainable approach to waste management

The acrylic acid-grafted functionalized base polyurethane foam (PAA-g-PUf) is synthesized through mutual radiation grafting technique using acrylic acid as functional monomers and polyurethane form (PUf) with macroporous structure as base polymer, for the extraction of lead from the aqoueous waste streams. The incorporation of functionality on PUf is identified and confirmed by FT-IR spectroscopy, degree of grafting and thermal stability by TGA–DSC technique while the surface morphology, and pores dimensions are evaluated by SEM techniques. The kinetics measurements indicate that the synthesized sorbent reaches its saturation sorption capacity within 10 min at ~ 25 °C under near-neutral pH condition. The monolayer sorption capacity of the synthesized PAA-g-PUf for lead ion (Pb2+) is calculated from Langmuir’s model and found to be ~ 257 mg g−1, which is quite good as compared to the other functionalized material available. These grafted foams are quite efficient over a wide range of concentrations and temperature of the experimental solutions. In this study, the adsorbed lead ions are eluted out in 0.5 M HCl strippent efficiently. These sorbents exhibit excellent reusability up to five cycles without losing appreciable capacity, suggesting better usability in real water samples for many cycles. The polyurethane foam used was obtained from municipal waste, and hence, they cannot generate any additional secondary waste to the environment and make the process more sustainable and economically viable.Graphical abstract

Modelling of carbon flows in the value chain of packaging plastics in the context of sustainable carbon management

The low share of plastic recycling means significant losses for the economy as well as for the environment, especially for plastic packaging materials since they are the largest end-use market for plastics and characterized by a typical short first-use cycle. The main polymers used in packaging applications are basic polymers, such as PE, PP, PS and PET, which consist mainly of fossil carbon locked up in polymer form. This study attempts to map carbon flows across the packaging plastics value chain with the goal to optimize carbon fixation in relevant polymers over multiple life cycles and minimize carbon loss to the atmosphere via CO2 emissions. Evaluating these carbon balances in the production, consumption and end-of-life treatment phase of these polymers provides more insight in the carbon losses during their life cycle. Three case studies were considered; (1) a baseline route (BASE), representing the current linear plastics economy model which is benchmarked with two theoretical sustainable scenarios: (2) an electrified (ELEC) and (3) a biobased (BIO) route. Specific parameters and assumptions in these three cases were adapted, such as feedstock type, recycling rate, type of recycling etc. Improved recycling rates and advanced recycling methods were applied in the sustainable cases and had a positive effect on carbon retention in products. Allowing a numerical comparison, a method was developed to quantify this carbon retention via the half lifetime of carbon in materials over multiple life cycles. The half lifetime evolved from 0.3 year in the BASE route to 2.0 and 2.6 years in the BIO and ELEC route, respectively. However, even these sustainable, optimized routes remained insufficient to embed carbon in plastic products for many years without too much carbon loss. It is inevitable that an enhanced (carbon) circularity in these routes comes by a certain energy cost; about 46 GJ more energy was required per extra recycled ton carbon in the ELEC route (compared to BASE). But at the same time this intensified carbon conservation leads to a CO2 emission reduction potential of 80 %. The present work illustrates the potential of chemical recycling, and carbon capture and utilization (CCU) techniques for end-of-life treatment of plastic packaging products, but additional process development and process intensification in all facets of the value chain are needed to minimize carbon leakage over multiple lifecycles. Hence, waste management policy could be an important instrument to support further enhancement in plastics circularity.