Ethylene Vinyl Acetate Research Articles

Experimental analysis of the effects of feedstock composition on the plastic and biomass Co-gasification process

Co-gasification is a feasible approach to manage fast-growing plastic and biomass waste issues. The current work examines air gasification of plastic waste blending with biomass. The influence of plastic-type and biomass characteristics on product distribution under the same operating condition was studied. Ethylene-vinyl acetate, high-density polyethylene, and polypropylene were the investigated plastics while the biomass materials considered were pine sawdust (PS), used ground coffee (UGC), and wheat straw (WS) are compared. Additionally, co-gasification and thermogravimetric analyses (TGA) of plastic and individual biomass components, namely, cellulose, hemicellulose, and lignin, were conducted to identify the nature of the synergy arising from plastic and biomass integration. Similarities in the chemical structure and composition of the investigated plastics resulted in the type of plastic marginally influencing product distribution. The gas composition included 4.6 vol% CH4, 37.5 % CO2, 5.3 % CnHm, 42 % CO, and 10.8 % H2, with yields of 5.9 wt% char, 39.5 wt% gas, and 54.8 wt% tar. Conversely, the type of biomass had a substantial effect on both gas composition and product yields. WS and UGC, characterized by higher hemicellulose and lignin content, generated more hydrogen with 14.4 and 13.3 vol%, respectively, and exhibited lower tar content (45.7 and 47.8 wt%) compared to PS, which has a higher cellulose content and yielded 54.8 wt% tar. During EVA/cellulose co-gasification, the predominant gases produced are CO and CO2, with H2 concentration of 7.2 vol%. In contrast, co-gasification of EVA/xylan and EVA/lignin yields 13.5 and 19.9 vol% hydrogen, respectively. Interactions and synergism between the plastic and biomass were found to be more intensified when the biomass contained greater proportions of cellulose and lignin. Co-gasification and TGA analyses indicated that plastic/cellulose and plastic/lignin interactions in the gas and solid phases (volatile-volatile and volatile-char interactions) and plastic/xylan interactions in the gas phase (volatile-volatile interactions) were significant. Modeling the predictability of the output data revealed that if interactions between the plastic and biomass components are accounted for, the co-gasification results are predictable with a credible accuracy for all biomass types. The predictability model offers a practical approach for selecting an appropriate co-gasification feedstock combination to give a targeted process performance.

The Effect of the Proportion of Rubber Components on the Properties of EVA/SBR/BR Foams

In actual production processes, pure ethyl vinyl acetate (EVA) foams have a high shrinkage rate, and the foaming matrix is prone to plastic deformation, even causing the collapse of bubbles. This limits the further application of EVA foams. In this study, we incorporated styrene butadiene rubber (SBR) and butadiene rubber (BR) into EVA to improve the mechanical properties and dimensional stability of EVA composite foams without sacrificing their low-density characteristics of low density. We used a melting index meter, rotorless vulcanizing meter and dynamic mechanical analysis (DMA) to characterize the changes in viscosity and energy storage modulus of the composite matrix. Scanning electron microscopy (SEM) was used to study the microscopic morphology of foams. The mechanical properties test results showed that the addition of SBR reduced the density of EVA/SBR/BR composite foams, and the addition of BR improved the mechanical properties and dimensional stability of the foams. By combining the advantages of both, the density of products is comparable to pure EVA, the tensile strength and the compressive strength are increased by 11% and 6.3% relative to pure EVA, respectively.

Syngas production through CO2-assisted catalytic pyrolysis of ethylene vinyl acetate (EVA) with a cobalt-based catalyst

Ethylene vinyl acetate (EVA) is a representative copolymer widely adopted across various sectors owing to its superior physiochemical properties; however, an environmentally benign protocol for the disposal of EVA waste has not yet been established owing to the various ratios of acetate to polyethylene. Therefore, in this study, we proposed an innovative thermochemical technique for converting EVA waste into energy resources, specifically syngas. CO2 was used to enhance the environmental sustainability of pyrolysis. Thermogravimetric analysis revealed that most of the EVA (approximately 99 wt%) was converted into pyrolytic oil and gases. However, the mechanistic features of CO2 in the pyrolysis of EVA could not be fully elucidated through single- or double-stage pyrolysis owing to the slow kinetics of the homogeneous reaction between CO2 and volatiles. To expedite the reaction kinetics, we used a cobalt (Co)-based catalyst (Co/SiO2). In the presence of Co/SiO2, the concentration of CO produced under CO2 was approximately 30-fold higher than that under N2. Furthermore, the homogeneous reactions resulted in fewer benzene derivatives and polycyclic aromatic hydrocarbons (PAHs) in the pyrolytic oil under CO2 conditions. These experimental findings suggest that CO2 and EVA could serve as valuable feedstocks for the production of energy.

Synergistic energy harvesting and humidity sensing with single electrode triboelectric nanogenerator

Humidity sensors using triboelectric nanogenerators (TENGs) technology can provide continuous operation without the need for additional batteries. These sensors provide sustainable and self-powered humidity monitoring solutions, that can be utilized in various agriculture platforms and food processing industries. In this work, a sol-gel method is utilized to process the bismuth ferrite (abbreviated as BFO) materials and a simple mould pressing method to obtain freestanding Ethylene-vinyl acetate (abbreviated EVA)-BFO composites. These composites were characterized to shed light upon structural and microstructural properties. The single electrode mode operating TENG was fabricated having 2 cm × 2 cm active area at various wt.% of BFO onto EVA-based composites to compare the electrical response. The 5 wt.% BFO-EVA-based composites/FEP-based TENG generates a voltage and current of 45 V and 800 nA. Further, the TENG device was tested for long-term stability for 400 s, and charging of various capacitors having capacitance values such as 0.1 μF, 1 μF, 4.7 μF, and 10 μF along with 3 times charging/discharging cycles of 0.1 μF capacitor have been demonstrated. The humidity sensing mechanism elucidated which follows the conduction process based on the Grotthuss proton hopping mechanism. The TENG demonstrates a sensitivity of 0.53 V/RH% over the relative humidity range from 25 % to 85 %. The powering of the wristwatch confirms that fabricated TENG can be a reliable power source for future low-power electronics.

Enhancement of porous asphalt mixtures modified with various fibers and ethylene–vinyl acetate polymer

Porous asphalt mixture is conventional hot mix asphalt (HMA) with substantially decreased fines, which produces an open-graded mixture that enables the water to flow through an interconnected void space. Porous asphalt is a permeable system that has a lot of benefits. However, because of its open structure, the durability of this mixture decreases, and both its stability and resilient modulus are much lower compared to the dense conventional asphalt mixtures. Also, the high void percentage may lead to an increase in the draindown proportion. Fibers (cellulose or mineral) and polymer-modified binders are recommended for porous asphalt mixtures, especially in hot and moderate climates. The objective of this study is to improve the porous asphalt mixture's performance by using ethylene–vinyl acetate (EVA) polymer-modified bitumen. Two types of fibers (cellulose fibers and glass wool fibers) were used, separately to determine the control mixture. Four different proportions of EVA polymer were added to the bitumen (1%, 2%, 3%, and 4%) and Scanning Electron Microscopy (SEM) was used for better investigating of the bitumen microstructure, then The Marshall mix design was used to determine the optimum EVA content (OEC) for the porous asphalt mixture. Several performance tests were conducted to investigate the characteristics of the porous asphalt mixture, such as the infiltration rate, binder draindown, the wheel track and the cantabro abrasion tests. The findings of the study conclude that the addition of EVA polymer to the porous asphalt mixtures enhances the performance as it increases stability by 20.8% and the infiltration rate by 20.6%. It decreases binder draindown proportion by 33.3%, cantabro abrasion loss by 25.1% and the rut depth at 5,000 cycles and 10,000 cycles by 29.8% and 19.7%, respectively.

A comparative study of mechanical crushing and pyrolysis techniques for separation and recovery of discarded polycrystalline silicon photovoltaic modules

With the rapid growth of the photovoltaic (PV) industry, efficient recovery and utilization of discarded polycrystalline silicon PV modules have attracted increasing attention. This study compares the application of mechanical crushing and pyrolysis techniques in the recovery of PV modules. The results indicate that while mechanical crushing can preliminarily disintegrate materials, its effectiveness in separating valuable materials such as silver and aluminum is limited, particularly for particles larger than 1 mm. In contrast, pyrolysis techniques demonstrate outstanding performance in removing organic matter and separating silicon wafers and glass, notably enhancing the recovery rate of large glass particles. However, the brittleness of silicon wafers presents a challenge during pyrolysis. Furthermore, the pyrolysis mechanisms of ethylene-vinyl acetate (EVA) film and backsheet materials are thoroughly discussed. The pyrolysis process of EVA film involves two stages: firstly, the preferential decomposition of acetyl oxygens on ester side chains, followed by further pyrolysis decomposition of the main chain and side chains to generate alkanes. Pyrolysis of polyethylene terephthalate (PET) begins with the generation of methyl and benzoyl radicals, while polyvinyl fluoride (PVF) and polyvinylidene fluoride (PVDF) pyrolysis initiates with the detachment of head-group units, followed by sequential detachment of chain units. Given the advantages of pyrolysis techniques, this study recommends them as the preferred method for PV module recovery.

Impact of Aligned Carbon Nanotubes on the Mechanical Properties and Sensing Performance of EVA/CNTs Composites

This study investigated the mechanical and sensing properties of ethylene-vinyl acetate (EVA)/carbon nanotubes (CNTs) composites in both film and fiber forms. The incorporation of aligned CNTs in the composite fibers possess improved mechanical properties and enhanced sensing performance compared to those of composite films with randomly dispersed CNTs. Thermogravimetric analysis revealed promising thermal stability, indicating potential applications for long-term usage. Cyclic tensile testing demonstrated that the fiber samples with better CNT alignment exhibit higher sensitivity, emphasizing the significance of CNT orientation in constructing an efficient conductive network for strain sensing. Considering the contribution of the CNTs orientation along the measuring direction, a model contains modification parameters was proposed, where a master curve was given, revealing the ideal potential of the EVA/CNTs composite fiber with perfectly aligned CNTs. This work provides valuable insights into the influence of CNT alignment on the mechanical and sensing properties of EVA/CNTs composites. The results underscore the importance of optimizing CNT orientation for enhanced sensing performance in various engineering applications.

Biodegradation of Ethylene Vinyl Acetate Using Klebsiella aerogenes EM011 Isolated from Effective Microorganisms

Biodegradation of Ethylene Vinyl Acetate Using Klebsiella aerogenes EM011 Isolated from Effective Microorganisms

Ethylene Vinyl Acetate Copolymer Emulsion-Modified Alkali-Activated Slag Repair Material: Mechanical Strength and Durability Linked to Microstructural Properties

Ethylene Vinyl Acetate Copolymer Emulsion-Modified Alkali-Activated Slag Repair Material: Mechanical Strength and Durability Linked to Microstructural Properties

Enhancing the Mechanical and Microstructural Properties of Low Expansive Clay Subgrade with Vinyl Acetate-Ethylene Polymer Incorporation

Enhancing the Mechanical and Microstructural Properties of Low Expansive Clay Subgrade with Vinyl Acetate-Ethylene Polymer Incorporation

Comparative analysis of rubber/cementitious interface enhanced by multiple modifying agents in rubber concrete - experimental and molecular dynamics studies

ABSTRACT Rubber concrete (RUBC) is an innovative eco-friendly material, but its weak internal interfaces and pores lead to reduced mechanical properties. This study compares the modification effects of ethylene-vinyl acetate copolymer (EVA), nano-calcium carbonate (Nano-CaCO3), and silane coupling agent (KH560) on the rubber-cement interface in RUBC to improve its mechanical properties. Macroscopic tests showed that all three modification methods improved RUBC’s compressive, shear, and flexural properties to varying degrees. Under the same conditions, RUBC modified with KH560 and Nano-CaCO3 outperformed EVA-modified RUBC in terms of mechanical performance. Microscopic tests (SEM, XRD, FTIR) indicated that KH560 and Nano-CaCO3 significantly increased cement gel formation, with KH560 notably enhancing the rubber-cement interface bonding. Molecular dynamics simulations showed that EVA, Nano-CaCO3, and KH560 increased interaction energy at the interface by forming more hydrogen bonds. However, KH560 formed stronger chemical bonds with C-S-H gel through Si-O-Si bonds. This study provides experimental and theoretical support for engineering applications aimed at enhancing RUBC’s mechanical properties through multiscale analysis.

Experimental study on full-scale glass roof panels with embedded laminated connections under the short-term and long-term loading

This experimental study covers a problematic of full-scale roof panels with four embedded laminated point connections under two types of loads - short-term loads on intact panels, and long-term uniform loads after the fracture of a thermally treated glass pane. Two types of panels consisting either of fully tempered, or heat strengthened glass plies in combination with float glass, were tested, and a specific type of Ethylene Vinyl Acetate foil was used as the interlayer. The first part of the study investigates short-term load bearing capacity of horizontally suspended panels. The load was applied in several loading and unloading cycles until the collapse of any connection. The second part of the study is focused on the residual load-bearing capacity of the roof panels after a partial failure, whereas a first step, the thermally treated glass plies were intentionally fractured. The long-term part of the experiment was performed within 65 days. During this period, the load was increasing until a collapse of any connection. In both types of experiment, a difference between specimens with fully tempered and heat strengthened glass was observed. In the short-term part of the experiment, the specimens with fully tempered glass failed in two steps and therefore, showed considerable post-failure load bearing capacity. On the other hand, the specimens with heat strengthened glass collapsed suddenly in one moment giving no post-failure capacity. In the long-term part of the experiment, the resistance of specimens with heat strengthened glass was higher than the resistance of specimens with fully tempered glass. Therefore, both types of panels might find its purpose in real applications if the needs of the structure are properly considered.

The use of polyetheretherketone material as an occlusal splint

Occlusal splint is a treatment alternative that gives positive results in reducing the symptoms of temporomandibular diseases. This treatment involves placing an appliance made of various materials specifically for the cutting and chewing surfaces of the teeth. The most popular materials used in the construction of occlusal splints are soft and hard acrylic-based materials such as polymethylmethacrylate, ethylene vinyl acetate, polycarbonate, polyethylene terephthalate and polyetheretherketone. PEEK is a high performance, semi-crystalline, thermoplastic and thermally stable polymer belonging to the polyaryletherketone family. PEEK, which has very good dimensional stability against intraoral temperature changes, is not affected by the intraoral chemical environment. Since PEEK material is chemically stable, has high biocompatibility and abrasion resistance, its use as an occlusal splint material has become widespread today. The aim of this review is to provide information about occlusal splints produced using PEEK material and digital procedures, which are becoming increasingly popular in dentistry, and to contribute to the literature.

Composite based on Poly(ethylene-co-vinyl acetate) with lead-titanate for gamma attenuation

The radioprotective ability of composite materials based on a poly (ethylene-co-vinyl acetate) matrix with dispersed lead titanate filler has been estimated. The filler was obtained from the environmentally friendly synthesis based on exchanging potassium ions for lead in potassium titanates. The gamma ray protective composites have low density, good mechanical qualities and are able to be reprocessed by high-performance extrusion or injection molding techniques. The present work is dedicated to assess mechanical and gamma ray shielding properties of poly (ethylene-vinyl acetate) composites with different lead titanate content (70, 80 and 90 wt percent of lead titanate). The study was carried out for the emission of 137Cs, 60Co and 241Am isotopes with energies 0.6617 MeV, 1.332/1.173 MeV and 0.0595 MeV respectively. The study of radiation-protective properties showed that for 137Cs radiation half value layer for the composite containing 90 wt% of lead titanate is three times higher than for neat lead: 2.1 and 0.7 cm respectively. For the 60Co emission, these values are more close: 1.9 cm for 90 wt% composite and 1.2 cm for lead. The layer of 0.5 cm of composite with 70 % lead titanate almost fully diminishes the low-energetic 241Am radiation, and hence, is superior to lead foil of the same length. Mass attenuation coefficients of 70% composite for 0.6617 MeV, 1.332/1.173 MeV and 0.0595 MeV are 0.088, 0.046 and 2.487 cm2/g respectively. The tensile elongation at fracture decrease is 460% for 70/30 lead titanate/poly (ethylene-vinyl acetate) and is equal to 6% for 90/10 lead titanate/poly (ethylene-vinyl acetate).

Preparation and Characterisation of Composites from Industrial Waste: Wood Flour and Expanded Ethylene Vinyl Acetate

Preparation and Characterisation of Composites from Industrial Waste: Wood Flour and Expanded Ethylene Vinyl Acetate

Efficient flame-retarded ethylene vinyl acetate composite containing microencapsulated expandable graphite and polyphosphoric acid

The most conspicuous problem regarding fire retardation of ethylene vinyl acetate (EVA) copolymer is that the flame-retardant efficiency of traditional fire retardants is very low. How to achieve high-efficient flame retardation has long been a big challenge. Herein, polyurea-modified microencapsulated expandable graphite (MEG) was synthesized through in-situ polymerization, and it was found that the proper combination of MEG and polyphosphoric acid (PPA) exhibits an unexpectedly high flame-retardant efficiency to EVA. The incorporation of just 5 wt% MEG/PPA enables EVA to achieve V-0 rating in UL-94 flammability test, increases its limiting oxygen index from 19.3 % to 25.7 %, and reduces its peak heat release rate by 72 % during combustion. The EVA/MEG/PPA composite, containing 5 wt% MEG/PPA, not only demonstrates improved fire retardancy, smoke suppression, and processability compared to virgin EVA, but also maintains good electrical insulation, water resistance, and mechanical properties. The high fire-retardant efficiency is ascribed to the larger expansion volume of MEG and the formation of high-quality intumescent char, which shield the polymer from burning. This work renders a simple and cheap approach for development of high-efficient flame-retarded EVA with good processability and mechanical property simultaneously.

Bridging the future: unveiling the latest innovations in ethylene vinyl acetate blends and composites through electron beam irradiation—a comprehensive review

Bridging the future: unveiling the latest innovations in ethylene vinyl acetate blends and composites through electron beam irradiation—a comprehensive review

Bonding performance of ethylene vinyl acetate reinforced carbon nanotube repair materials

Inorganic repair materials have significant advantages such as high durability, high strength, and good corrosion resistance. However, their low bonding strength and inadequate tensile performance are clear disadvantages, which often results in problems like cracking, delamination, and insufficient repairing strength. In the current study, a new repair material is developed, which enhances the interfacial bonding performance of carbon nanotubes (CNTs) repair materials by introducing ethylene vinyl acetate (EVA). The bonding strength of composite specimens was tested by splitting tensile test. Then the microstructure analysis of the repaired materials was conducted by X-ray computed tomography, backscattered electron imaging, and scanning electron microscopy. The phase composition of the repair material was further analyzed by Fourier transform infrared spectroscopy. Finally, the bonding mechanisms of EVA reinforced CNTs repair materials were discussed. The results indicate that the interaction between EVA and CNTs can enhance the bonding performance of repair materials. Additionally, the polymer film formed by EVA within the repair material can refine the pores, thereby reducing the porosity of the interfacial transition zone and that of repair materials. The electrostatic repulsion between EVA and CNTs contributes to the uniform dispersion of CNTs within repair materials.

First evidence of microplastics and their characterization in yellow-legged gull (Larus michahellis michahellis, Naumann, 1840) pellets collected from the Sfax salina, southeastern Tunisia

The aim of this work was to provide evidence on the presence of microplastics (MPs) in regurgitated Yellow-legged Gull pellets (n = 18) from Sfax salina (south-eastern Tunisia). This artificial area is subject to high anthropogenic pressure and hosts Yellow-legged Gulls, which are at the top of the trophic chain and can be used as sentinel species to monitor litter in the environment, including plastic pollution. The total number of MPs found in the samples was 309, 63.8 % fibres (4.95 ± 3.51 MPs/g) and 36.2 % fragments (2.87 ± 1.74 MPs/g). Micro-FTIR analysis evidenced that a large proportion of the fibres was attributed to artificial cellulose (40.7 %). Ethylene vinyl acetate (EVA) and polyethylene (PE) were found in the fragments.

Preparation and Characterisation of Composites from Industrial Waste: Wood Flour and Expanded Ethylene Vinyl Acetate

Preparation and Characterisation of Composites from Industrial Waste: Wood Flour and Expanded Ethylene Vinyl Acetate