Ethylene Vinyl Acetate Research Articles

A comparative study on the persistence and viability of SARS-CoV-2 wild-type and omicron variant on artificially contaminated surfaces: the role of fomites

ABSTRACT Indirect transmission of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been investigated but it is still not completely understood. The present study aimed to compare the persistence and viability of the lineage B.1 and omicron BA.1 subvariant in five daily-use materials to evaluate the role of fomites as a possible source of infection. Artificial contamination was performed in the first set of materials, ethylene vinyl acetate (EVA), cardboard, polystyrene, aluminium, and plastic. Further surfaces using BA.1 (glass, plexiglass, cotton, polyester, and tetrapak) were conducted. The persistence, viability of Vero E6 cell cultures and the residual infectivity of the two lineages were evaluated over 5 days. The results showed different stabilities between the tested matrices. In cotton and polyester, the RNA was undetectable in 24 and 48h post-contamination (p.c.), respectively, and the virus was not viable within 30 min, while in the other surfaces, both lineages, RNA was detectable until 120h p.c. A rapid decay of the viral load was revealed on cardboard, mostly for the omicron variant. Furthermore, on all the materials, longer stability of BA.1 was demonstrated, but showing a less intense CPE than the wild-type. EVA was the material that was able to better sustain virus stability as the virus developed CPE up to 72h p.c. In conclusion, the potential spread of SARS-CoV-2 through fomites is conceivable, albeit it is difficult to establish the real capacity to infect people. Nevertheless, thise information is fundamental to adopting the appropriate measures to mitigate the spread of SARS-CoV-2 and its variants.

Experimental analysis of tribological performance of base ficus carica vegetable oil with different polymers as additives using four ball tribometer

The need to use vegetable lubricants has been driven by the widespread concern for environmental issues, especially in industries that overuse petroleum lubricants. This research examined the tribological characteristics of vegetable-based lubricants by adding additives such as ethylene–vinyl acetate (EVA) and Eichhornia crassipes carboxymethyl cellulose (EC-CMC) polymers to study the viscometric response of the lubricants. The test was conducted using four ball-tester, and analyzed in terms of coefficient of friction (COF), wear scar diameter (WSD), and wear scar rate, respectively. The results showed that with the addition of each additive enhanced the tribological properties significantly but yielded poor results with 0.5% additives for both samples. The characterization investigation showed that ficus carica (Fig) oil responded effectively to the addition of various additives when conducted thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. Under 100 kg load and speed of 1200 rpm, base Fig lubricant yielded a higher COF of 0.193, while blended EVA and EC-CMC gave lower COF of 0.161 and 0.171, while the lowest wear scar diameter was with 1.5 wt% EVA (0.39 mm) and 1 wt% EVA (0.41 mm), respectively. Comparing all the lubricants under 1500 rpm, the base Fig lubricant yielded 0.317, while 1.5 wt% EVA, 1.5 wt% EC-CMC, SEA 5W 30 gives COF of 0.287, 0.263, and 0.239, respectively. The study revealed that the reduction in the COF and wear scar diameter was due to the formation of the film by the included additive.

Novel EPE co-extruded encapsulating films with UV down-conversion power gain effect for highly efficient solar cells

How to maintain or even improve the performance of solar cells under the influence of high temperature, high humidity and intense ultraviolet light has always been a challenging research topic. Here, we propose a novel and effective solution by combining the benefits of EVA (ethylene vinyl acetate), POE (polyolefin) and UV down-conversion (UV-DC) fluorescent nanomaterial (Sr2-xMgSi2O7-x: Eu2+, Dy3+) to construct the first commercially available UV-DC EPE co-extruded encapsulating film with a three-layer composite structure. On the one hand, the UV-DC EPE incorporates the high adhesive strength of EVA and the strong weather resistance of POE. On the other hand, the UV-DC EPE can also convert the UV irradiation, inefficient for power generation and easily cause damage to solar cells, into visible light range with high quantum efficiencies. Therefore, we discover that the UV-DC EPE not only shows higher stability than other encapsulation films under potential-induced degradation (PID), pressure cooker test (PCT), UV and natural sunlight aging tests, but also enhances the power generation efficiencies by 0.3% and 2.3% compared with the UV-transmitting and the UV-filtering EPE films, respectively. The progress in this work breaks the stereotypical definition of encapsulation that only slows down attenuation, but integrates the advantages of power gain effect, high stability, and low cost into the novel encapsulation material and technology, which is expected to be promoted and industrialized in the near future.

Moisture induced degradation in field-aged multicrystalline silicon photovoltaic modules

Moisture ingress is one of the key fault mechanisms responsible for photovoltaic (PV) devices degradation. Understanding moisture induced degradation (MID) mechanisms in field-aged PV modules is more reflective of the reality in the field. In the present work, MID products of reclaimed solar cells from 20-year-old field-aged silicon PV modules is investigated. The defective areas in the PV modules were identified using visual inspection, electroluminescence (EL), ultraviolet fluorescence (UV–F), and infrared thermal (IR-T) techniques. SEM-EDS analysis is used to elucidate the role of moisture on the observed degradation mechanisms. Degradation of the ethylene vinyl acetate (EVA) encapsulation produces acetic acid, carbon dioxide, phosphorus, sulfur, fluorine, and chlorine. Migration of metal ions under the influence of moisture ingress makes the formation of oxides, hydroxides, sulfides, phosphates, acetates, and carbonates of silver, lead, tin, copper, zinc, and aluminum feasible. Also, other competing reactions can lead to the formation of stannates of copper, silver, sodium, and zinc. Another observation is that, in the presence of MID species, Pb is preferentially corroded (to form lead acetate complexes) instead of the expected sacrificial Sn in the solder. These MID species account for different defects and fault modes that lead to parasitic resistance losses. This is witnessed by the 1.2%/year degradation in the Pmax of the PV module.

Removal of encapsulant Ethylene-vinyl acetate (EVA) from solar cells of photovoltaic modules (PVMs)

Photovoltaic modules (PVMs) are a very promising way to meet future energy needs. As traditional energy sources aren't sustainable, the only way to meet future energy needs will be through renewable energy sources. The amount of e-waste expected to generated in the near future is an important concern. Ethylene-vinyl acetate (EVA) encapsulatethe solar cell, and this layer must be removedto get to the other materials that can be recycled. EVA can be removedwith the help of heat treatmentand organic solvents. In this work, the interaction of EVA with different organic solvents was studied. For measuring interaction, the swelling of EVA caused by the organic solvent penetrating andaccommodatinginsidethe polymer matrix is considered. The swelling also caused EVA to lose its mechanical strength, making it easy to remove. The reaction of organic solvents with EVA is explained in terms of functional groups of organic solvents. When compared to other solvents, chlorinated hydrocarbons such as trichloroethylene, carbon tetrachloride, chloroform can effectively cause EVA swelling. Furthermore, aromatic hydrocarbons interact well with EVA. Aromatic hydrocarbons are relatively better choice than chlorine-containing hydrocarbon for industrial application based on sustainability of the process.

Stable passivation of cut edges in encapsulated n-type silicon solar cells using Nafion polymer

In this study, the edge passivation effectiveness and long-term stability of Nafion polymer in n-type interdigitated back contact (IBC) solar cells are investigated. For new module technologies such as half-cut, triple-cut, or shingled modules, cutting of the cells introduces unpassivated edges with a high recombination rate and this limits the module power. These cut edges can be “repassivated” after cutting and in this work Nafion polymer is used to achieve this. First, different edge types, namely emitter edges (n+/n/p+) and back surface field (BSF) edges (n+/n/n+), as well as different cutting techniques such as laser cut and cleave (L&C), thermal laser separation (TLS), and mechanical cleaving are evaluated. It is found that TLS and mechanical cleaving enable good repassivation on both BSF and emitter edges. Second, industrial-size IBC solar cells are made to assess the effect of the edge repassivation on performance. On 1/4-cut M2 size IBC cells with two emitter edges, efficiency is improved by over 0.3%abs. However, an efficiency improvement was not observed for similar cells with BSF edges, due to an insufficient passivation at the bulk edges. Last, the real-world stability of the Nafion repassivation is evaluated in industrially relevant module stacks by laminating the repassivated wafers with ethylvinylacetate (EVA) or polyolefin elastomer (POE) encapsulants and then exposing them to industry standard testing of 1000 h under damp heat conditions (85 °C, 85% relative humidity). The tests reveal that the repassivation is stable in EVA encapsulants but not in POE.

Tribological Performance Evaluation of Vegetable Lubricant Incorporated Ethylene Vinyl Acetate (EVA) and Tertiary-Butyl-Hydroquinone (TBHQ) Nanoparticles

Tribological Performance Evaluation of Vegetable Lubricant Incorporated Ethylene Vinyl Acetate (EVA) and Tertiary-Butyl-Hydroquinone (TBHQ) Nanoparticles

The Out-Of-Plane Compression Behavior of In Situ Ethylene Vinyl Acetate (EVA)-Foam-Filled Aluminum Honeycomb Sandwich Structures.

In this study, the mechanical behavior of aluminum honeycomb (AHC) sandwich structures filled with ethylene vinyl acetate copolymer (EVA) foam in situ under out-of-plane compression loading was investigated experimentally. Both non-filled and EVA-foam-filled sandwich specimens with three different AHC core cell sizes (5.20, 6.78, and 8.66 mm) were studied to correlate the foam-filling effect with a key structural parameter. The results showed that compression characteristic properties such as peak stress, plateau stress, and absorbed energy per unit volume of the sandwich structure increased with EVA foam filling. The structure showed high recoverability when the compression loading was removed due to the viscoelastic nature of EVA foam. Cored EVA sandwich with 8.66 mm AHC cell size was recovered at 44% of the original thickness. This result promises groundbreaking applications such as impact-resistant and self-healing structures. The microstructures were also observed using scanning electron microscopy (SEM) to investigate the failure and the recoverability mechanisms.

Concurrently improving fire safety and processability of ethylene vinyl acetate copolymer by expandable graphite and polyphosphoric acid

AbstractEthylene vinyl acetate copolymer (EVA) was modified by expandable graphite (EG) and polyphosphoric acid (PPA) in melt state and the obtained EVA/EG/PPA composite was studied regarding its fire behavior, thermal endurance, water resistivity, processability, and mechanical property. The outcomes evince that the combination of EG and PPA in proper mass ratio can improve fire retardancy, thermal stability, processability, and reduce smoke and toxic gas releases of EVA upon combustion significantly. The EG/PPA combination exhibits very high flame retardant efficiency to EVA in that only 10 wt% loading is enough to make EVA obtain V‐0 rating in UL‐94 test. Moreover, the flame‐retarded EVA/EG/PPA composite displays excellent water resistance and acceptable mechanical property. The EVA/EG/PPA (90/7.5/2.5) composite can produce coherent intumescent char on composite surface, which has good heat endurance and hinders heat transmission from fire to interior of composite. The flame retardation occurs in condensed phase and the intumescent char plays a pivotal role. The presence of PPA endows EVA composite with good melt flowability, which has presented a striking contrast to other flame retardants.Highlights The combination of EG and PPA has very high flame retardant efficiency to EVA. The EVA/EG/PPA composite has better fire safety and processability than EVA. The EVA/EG/PPA composite still maintains acceptable mechanical property. The expanded char from EVA/EG/PPA composite hinders heat transfer effectively.

Spatiotemporal distribution of microplastics in true frogs (Ranidae:Pelophylax) populations from Türkiye

Microplastics (MPs), which are of increasing concern in almost all ecosystems, continue to be an environmental threat. In the present study, the presence of MPs is investigated by using the gastrointestinal tracts (GITs) obtained from the true frog individuals sampled in the past years. The sample consists of a total of 146 individuals obtained from various regions of Türkiye. The results show that MPs were found in 87 adult frog individuals. The most predominant shape of MPs found was fiber, with a predominance of transparent color, and ethylene-vinyl acetate (EVA) was also the most abundant microplastic material. The highest amount of MPs among adult frog populations were found in the Denizli province. The size of MPs ranged between a minimum of 66 and a maximum of 3770 μm. In addition, no relationship was found between the body length and weight of the frogs and the sizes of MPs. Historically, most MPs were found in samples from 1990 and the highest content in terms of both color and material was detected in 1990. MPs were detected in almost all the years studied, but microplastic abundance varied from year to year. These results can be explained by the number of samples, habitat, and feeding behavior of adult frogs.

A novel strategy for preparing ethylene‐vinyl acetate composites with high effective flame retardant and smoke suppression performance by incorporating piperazine pyrophosphate and Ce‐MOF

AbstractCerium‐containing metal organic framework defined as Ce‐MOF was prepared and then combined with piperazine pyrophosphate (PAPP) for preparing flame retardant ethylene vinyl acetate (EVA) copolymer composites. The samples of EVA/PAPP/Ce‐MOF achieved UL‐94 V‐0 rating with the limiting oxygen index (LOI) value of 31.3% when 17 wt% PAPP/Ce‐MOF with the mass fraction of 97:3 was introduced. Under the same loading amount of PAPP, the EVA/PAPP only obtained UL‐94 V‐1 rating with the LOI value of 26.9%. Cone calorimeter test confirmed that the total heat release and total smoke production of EVA/PAPP/Ce‐MOF significantly reduced from 132.8 MJ m−2 and 11.5 m2 for EVA/PAPP to 98.8 MJ m−2 and 7.3 m2, with a reduction of 25.6% and 36.5%, respectively. Besides, the maximum smoke density decreased from 488.8 and 375.9 for EVA and EVA/PAPP to 177.5 for EVA/PAPP/Ce‐MOF. It indicated that the addition of Ce‐MOF and PAPP effectively exerted synergistic flame retardant and smoke inhibition effect for EVA. Moreover, the addition of Ce‐MOF enhanced the compatibility of PAPP with EVA matrix, and water resistance of EVA/PAPP/Ce‐MOF was higher than that of EVA/PAPP. The x‐ray photoelectron spectroscopy texts of residual char of EVA composites indicated that the cerium ion complexed with phosphoric acid and polyphosphate generated by the thermal decomposition of PAPP and then more phosphorus elements remained in condensed phase. As a result, the sufficient, crosslinking and dense char layer with excellent intensity was formed, and the heat, combustible gas and smoke were efficiently inhibited. Consequently, the EVA materials were endowed excellent fire safety as well as low heat and smoke release.

Influence of TPU/EVA Phase Morphology Evolution on Supercritical Carbon Dioxide Extrusion Foaming.

Ethylene-vinyl acetate copolymer (EVA) was added at different contents to the thermoplastic polyurethane (TPU) matrix to form a non-compatible blending system, and foaming materials with high pore density were prepared using the supercritical carbon dioxide extrusion method. The influence of the phase morphology and crystal morphology of the TPU/EVA blend on its foaming behavior was studied. The results show that EVA changed the phase morphology and crystal morphology of the blends, leading to the improved melt viscosity and crystallinity of the blend system. At the same time, interfacial nucleation increases the density of cells and decreases the cell thickness and size, which is beneficial for improving the foaming properties of the blends. For the EVA content of 10% (mass fraction), the cell size is small (105.29 μm) and the cell density is the highest (3.74 × 106 cells/cm3). Based on the TPU/EVA phase morphology and crystal morphology, it is found that the sea-island structure of the blend has better foaming properties than the bicontinuous structure.

Analysis of Environmental Stresses on the Mechanical Properties of Laminated Glass Composites: A Review of Experimental Results and Outlook

Laminated glass composites are composed of two or more layers of glass and a thermoplastic elastomeric interlayer securely glued together in an autoclave at high temperature and pressure. This composite material which significantly enhances the performance of glass before and after breakage, is desirable for various engineering applications. The main elastomeric interlayer comprises Polyvinyl butyral (PVB), SentryGlas (SG), Ethylene-vinyl acetate (EVA), and Thermoplastic Polyethylene (TPU). These interlayer materials have different unique features which offer a variety of performance benefits for engineering purposes. However, the structural response of laminated glass composites' elements and polymeric interlayers is typically prone to structural modifications relative to temperature applications and other environmental actions such as humidity and solar irradiation. This review compares the weathering resistance of the most common interlayers used in laminated glass composites based on available experimental literature findings. The main mechanical and accelerated ageing tests of laminates with different interlayer materials are summarised, giving evidence of the impact of these environmental actions on the viscoelastic and mechanical properties of laminated glass composites plates. This research provides valuable references for predicting the long-term behaviour and risk evaluation of laminated glass composites under diverse ageing conditions.

Visual Detection of Coumarin and Umbelliferone for Beverage Safety Based on Eu(III)‐Functionalized HOF Hybrids: Further Constructing an SVM‐Assisted Digital Anti‐Counterfeiting Platform

AbstractThe development of rapid, sensitive, and intuitive intelligent fluorescent materials (IFMs) for monitoring beverage safety is important for human health. In this study, an emerging IFM, a dual‐emitting Eu3+‐functionalized hydrogen‐bonded organic framework (Eu@HOF, Eu@1), is fabricated through coordination post‐synthetic modification. The ligand‐to‐metal charge transfer‐induced energy transfer (LMCT‐ET) from 1 to Eu3+ provides Eu@1 with palpable red fluorescence. Eu@1 as a sensor can specifically discriminate coumarin (Cou), a common spice used in beverages but a suspected carcinogen, with high sensitivity, high efficiency, and excellent anti‐interference. Eu@1 can also quantitatively distinguish 7‐hydroxycoumarin (umbelliferone, Ulf), a metabolite of Cou, in chromatic and ratiometric modes. In realistic milk and soy milk samples, the detection limits (DL) of Eu@1 for Cou are 0.0979 and 0.0511 mg L−1, respectively, whereas that of Ulf in practical serum samples is 0.0099 mg L−1. Furthermore, based on the polyethylene‐vinyl acetate (PEVA) films, three digital anti‐counterfeiting platforms with multiple encryption information are constructed, assisted by a support vector machine. This work proposes a facile pathway for preparing Eu@HOF fluorescent sensors to determine beverage safety and opens the possibility of designing an efficient and precise multifunctional digital anti‐counterfeiting platform via machine learning.

Environmental impact of pavements formulated with bitumen modified with PE pyrolytic wax: A comparative life cycle assessment study

This study aimed to evaluate the environmental impacts of various bitumen modifiers on asphalt production, given its significant contribution to greenhouse gas emissions, waste generation, and the depletion of non-renewable resources. Four bitumen modifiers were compared, namely, recycled polyethylene (PE) pyrolytic wax, ethylene-vinyl acetate (EVA), recycled polypropylene (PP), and a combination of PE pyrolytic wax and PP, using the life cycle assessment method with one km of road as the functional unit. Results showed that the use of asphalt mixtures formulated with bitumen modified with PE pyrolytic wax had the lowest environmental impact, with a 5.9% decrease compared to traditional pavement. This reduction was attributed to the generation of environmental credits from pyrolysis and a decrease in the amount of virgin bitumen needed for asphalt mixture formulation. Conversely, binders modified with EVA and recycled PP had the highest environmental impact due to high maintenance requirements and environmental impacts in their corresponding additives, with 12% and 5% more impact than traditional pavement, respectively. The study further noted that overall environmental performance was highly sensitive to the amount of bitumen required and the yield of wax produced during pyrolysis, indicating the importance of carefully selecting bitumen modifiers. Based on the findings, the study recommends the use of asphalt mixtures formulated with bitumen modified with PE pyrolytic wax due to their favourable environmental performance.

Mechanically robust, superelastic and lightweight composite foam enabled by hydrogen bond cross-linking

The structure collapse and significant plastic deformation of lightweight polymeric foams under various external mechanical loads has become an increasing challenge for practical applications. Herein, we report an efficient approach for fabricating the lightweight and highly porous ethylene vinyl acetate copolymer (EVA)-based composite foams with structural robustness and mechanical resilience by introducing flexible carboxylated EVA (EVA-COOH). The cells micromorphology of composite foams can be flexibly controlled by tuning the EVA-COOH concentration during the plasticizing process. Owing to the hydrogen bond cross-linking induced by EVA-COOH, the resulting lightweight composite foams (EVA-18/EVA-COOH) with low density (∼0.168 g/cm3) exhibit higher mechanical robustness including ultimate strength (∼1.66 MPa), tear strength (∼6.48 KN/m) and compressive stress at 50 % compressive strain (∼0.26 MPa) compared to that of traditional foams (such as EVA-18 composite foams). Strikingly, the elastic network provided by EVA-COOH also endows the composite foams with low hysteresis cycle performance at 50 % strain, stable elastic storage capacity at 20 % strain and high elasticity (rebound=∼44.2 %). It is envisaged that the mechanically robust, superelastic and lightweight composite foams offer a basic platform for utilizing EVA-based materials in various emerging applications, ranging from sensors to tissue engineering scaffold.

Nonisothermal crystallization kinetic behavior of pure ethylene-Vinyl acetate copolymers and ethylene-Vinyl acetate copolymer/nitrile rubber thermoplastic vulcanizate

Thermoplastic vulcanizate (TPV) made from the ethylene-vinyl acetate copolymer (EVA)/nitrile rubber (NBR) blend was fabricated using the dynamic vulcanization method. Differential scanning calorimetry (DSC) was utilized to analyze the nonisothermal crystallization kinetics of both pure EVA and EVA/NBR TPV. The nonisothermal crystallization mechanism was evaluated using the Avrami method modified by Jeziorny, the Ozawa method and the Mo method. The results demonstrate that the nonisothermal crystallization of both pure EVA and EVA/NBR TPV can be adequately described by the Avrami method modified by Jeziorny and the Mo method, while the Ozawa method is not applicable. By elevating the cooling rate, there was a reduction in the crystallization temperature and t1/2 for both pure EVA and EVA/NBR TPV, while the degree of crystallization increased. At the same cooling rate, the crystallization temperature of the EVA/NBR TPV was found to be higher than that of the pure EVA, suggesting that the presence of NBR facilitated the nucleation of the EVA matrix within the EVA/NBR TPV. Moreover, a steric hindrance effect existed in the NBR phase of EVA/NBR TPV at the same cooling rate, resulting in a larger t1/2 compared to that of the pure EVA, indicating hindered crystal growth.

Effect of different waste plastic modifiers on conventional asphalt performance: optimal preparation parameters determination and mechanism analysis.

The typical treatment of waste plastics has become a global environmental problem. In light of recent developments, waste plastics used as asphalt modifiers offer an efficient approach to solve this problem. This paper studied the effects of three kinds of waste plastic-modified asphalts (WPMA), with polypropylene (PP), polyethylene (PE) and ethylene-vinyl acetate copolymer (EVA) as their respective modifiers, on the conventional asphalt performance. Furthermore, an orthogonal experimental design (OED) was used to determine the preparation parameters of WPMA. Thereafter, thermogravimetric-differential scanning calorimetry (TG-DSC) and Fourier transform infrared spectroscopy (FTIR) were employed to expound the mechanism of WPMA. It was then subsequently ascertained that the optimum preparation parameters of PP-modified asphalt (PPMA) and PE-modified asphalt (PEMA) were 170 °C, 3000 rpm, and 30 min, while the optimum preparation parameters of EVA-modified asphalt (EVAMA) were 180 °C, 3000 rpm, and 30 min. In addition, WPMA displayed better high-temperature performance and are inherently more suitable for pavement in high-temperature regions. Ultimately, this study will effectively solve the disposal of waste plastic and promote the research and application of WPMA in the future.

Personalization of Complex Vaginal Inserts of Ethylene Vinyl Acetate via 3D‐Printing

AbstractEthylene vinyl acetate (EVA) with a vinyl acetate (VA) content of 28 wt.% (EVA28) is frequently used in vaginal inserts and subcutaneous implants due to its biocompatibility and drug‐releasing properties. Traditionally being processed via hot melt extrusion, its processibility via filament‐based 3D‐printing was reported to be impossible. Consequently, no applicable customization concepts for vaginal inserts exist. For the first time, the fabrication of 3D‐printed vaginal inserts (urethra pessaries) of EVA28 is demonstrated by optimizing its viscosity, employing 3D‐printer adaptations, and carefully selecting printing parameters. The infill pattern of fully filled mono‐material pessaries (determining the number and orientation of weld lines) significantly affects the in vitro release of the model drug progesterone (P4), while other critical parameters (the pessary's mechanical properties and appearance) remain unaffected. Weld lines act as diffusion barriers for dissolved P4 molecules. Hence, a high number of weld lines to be crossed reduces the overall P4 diffusivity in EVA28, decreasing the P4 release rate. To further control the P4 release, innovative multi‐material pessary designs (additionally comprising EVA with a VA content of 9 wt.% that is also used in vaginal inserts) allow to tailor the in vitro drug release and the mechanics individually. Thereby, this work highly improves the mechanistic understanding on drug release modifications from 3D‐printed non‐biodegradable devices. The findings build the basis for the first application of customized vaginal inserts, as they are based on polymers used in corresponding marketed products for more than 20 years.

Balancing the sustainable component of ethylene-vinyl acetate for achieved better compatibility improvement of wax-based warm mix additives in bitumen

The ethylene-vinyl acetate (EVA) polymers are always doped into waxy bitumen to inhibit network of wax crystals in bitumen. However, the compatibility improvement behaviors between wax-based warm mix (WWM) additives and bitumen by EVA are not clear, and the sustainable components of EVA for corresponding WWM additives to achieve better compatibility improvement are also not determined. This paper investigated compatibility improvement behaviors between commonly used WWM additives and bitumen after the addition of EVA to obtain sustainable components of EVA through experimental method of activation energy of viscous flow (AEVF) and density function theory-molecular dynamic (DFT-MD) calculations. The results show that the repulsions between the end of main-chain with highest electronegativity in WWM additives and polar molecules of EVA can alleviate the aggregation behaviors of WWM additives and EVA displays the best and worst compatibility improvements for additives with shortest and longest carbon chains, respectively. The dispersed asphaltenes combined with EVA can form the composite wax inhibitors (WIs) systems to increase diffusion coefficient and reduce percentage increment values of cohesive energy density (CED) to further disrupt ordered degree of WWM additives. On this basis, the sustainable carbon numbers of main-chain for EVA that are slightly less than average carbon numbers of WWM additives will help to better improve the compatibility of WWM additives. This investigation can provide the inspiration on how to choose the sustainable components of EVA to achieve high-efficiency compatibility improvement for corresponding warm mix asphalts (WMAs) with different average carbon numbers.