Ethylene-vinyl Acetate Emulsion Research Articles

Improvement of Core–Shell Lightweight Aggregate by Modifying the Cement–EPS Interface

To improve the interfacial compatibility between cement matrix and expanded polystyrene (EPS) in core-shell lightweight aggregates (CSLA), the effects of sodium silicate, polyvinyl acetate (PVA) emulsion, vinyl acetate-ethylene (VAE) emulsion, acrylic acid, and acetic acid on the cement-EPS interface were investigated. The density of the interface was studied by scanning electron microscopy (SEM), and the effect of interfacial agents on the hydration process of cement was studied by the heat of hydration and induction resistivity. The macroscopic properties of the interface of the CSLA were characterized by the "leak-white" rate, drop resistance, and numerical crushing strength. The results show that the sodium silicate densifies the interface by generating hydration products on the EPS surface. At the same time, organic acid enhances the interfacial properties of EPS and cement by increasing the surface roughness, and allowing hydration products to grow in the surface micropores. In terms of the cement hydration process, both interfacial agents delay the cement hydration. Above all, with comprehensive interface properties, "leak-white" rate, and mechanical properties, VAE emulsion and sodium silicate can achieve the best performance with a final crushing resistance of 5.7 MPa, which had a 46% increase compared with the reference group.

Investigation on effect of EVA on properties of desert sand-based permeable materials

This paper aims at studying the effect of adding ethylene vinyl acetate (EVA) emulsion on the properties of desert sand-based permeable materials and explore the modification effect and mechanism of polymers. EVA emulsion can improve the fluidity of the slurry, and significantly improve the compressive strength, water permeability and freezing resistance at 10 % content. The EVA emulsion cured film is adsorbed on the surface of anhydrous cement particles. At the same time, the ester group in emulsion reacts with Ca2+ following hydrolysis, which inhibits the early hydration process of cement and reduces the early heat release. However, it has a non-significant impact on the later-age hydration and ensures the strength development of cement at the later stage. The emulsion can affect the pore structure of the material and can significantly increase the micropores content at 10 % content. The physical and chemical actions of polymer together influence the hydration process of cement and improve the bonding between desert sand and cement paste.

Effect of Application of VAE Emulsion and Water-Soluble Resin Binder on the Properties of Coated Paper

When binders with different physical properties were applied to the pre-coat layer, coating layers having different properties were formed. This was because the characteristics of the top-coating vary depending on the top-coating layer. In particular, the properties of this top-coating layer affected the final printability. Vinyl acetate ethylene (VAE) emulsion binders offer advantages as an alternative resource because natural gas provides the base substance for polymer production. The Tg of VAE emulsion binders can be easily adjusted, so the desired physical properties can be adjusted. Therefore, in this study, SB-latex and VAE emulsion binders with different Tg were applied to the pre-coating layer. In addition, poly vinyl acohol (PVA) was applied as a co-binder, and the printability was evaluated by observing changes in physical properties of the pre-coating layer and the top-coating layer. As a result, as the Tg increased, the surface roughness of the coated paper increased while the paper gloss decreased. In addition, when PVA was blended, a tendency simillar to paper gloss was showed. Therefore, It is considered that this is because the voids formed by the pigment and the binder form different structures.

Effect of Application of Vinyl Acetate Ethylene Emulsion Binder and Type of Pigment on the Quality of Inkjet Paper

Zeolites and precipitated calcium carbonate (PCC) were applied together with a vinyl acetate ethylene (VAE) emulsion to identify an alternative pigment for silica to improve runnability and develop the application technology for the VAE emulsion. The low shear and high shear viscosity of the coating color were decreased when zeolites were mixed with PCC. The coating color exhibited lower shear and higher shear viscosity when the emulsion contained VAE than when it containing poly(vinyl) alcohol. Silica with a large specific surface area and pore volume exhibited a small surface contact angle, and the coating color also showed a smaller contact angle with zeolites having a porous structure than with PCC. Silica with a large specific surface area and pore volume showed high print density. For each type of pigment, the print density of coated paper was higher when using zeolites than when using PCC. When the VAE emulsion binder was applied, the ink density decreased.

Effect of Vinyl Acetate Ethylene Emulsion Formulation and Poly (vinyl alcohol) Molecular Weight on the Quality of Inkjet Paper

The study aim was to evaluate the effect of mixing of a water-soluble polymer, poly (vinyl alcohol) (PVA), and an emulsion binder, vinyl acetate ethylene (VAE), on the properties of the coating color and to identify the factors affecting the design of the coating color formulation for inkjet paper. The test compositions of the coating color used PVA and VAE emulsion binders of different molecular weights, and the properties of the prepared coating color and coated paper were analyzed. As the mixing ratio of the VAE emulsion to PVA increased, the viscosity of the coating solution decreased, but when the mixing ratio was constant, the coating color using low-molecular weight PVA had low viscosity. As the VAE emulsion mixing ratio and PVA molecular weight increased, the contact angle of the coated papers increased, but the ink density of the coated paper decreased.

Preparation and characterization of ultra-lightweight fly ash-based cement foams incorporating ethylene-vinyl acetate emulsion and waste-derived C-S-H seeds

Recycling of accumulated fly ash (FA) from the coal-burning power plant positively avoids the severe environment problems. Also, to achieve the energy-savings in building facades, the excellent fire-resistant and heat-insulating high-porosity fly ash-based foamed cement (ULFC) with dry density less than 160 kg/m3, was formulated in this work. Ethylene-vinyl acetate (EVA) emulsion was introduced into ULFC slurry, and a lab-made hardening accelerator named A-3 and waste-derived calcium silicate hydrate (C-S-H) seeds from the discarded cement foams were also developed and mixed to regulate the early hydration rate of this green FA-based binder incorporating FA up to 50 wt%. Results revealed that under the optimum preparation parameters, the dry density, compressive strength and heat conductivity of ULFC at 28 days can approach to 154.7 kg/m3, 0.47 MPa and 0.0514 W/(m·K), respectively. Morphological analysis elucidated that the polymeric EVA film solidified at the gas–solid interface and well-interwined with hardened cement stone to improve the compressive strength when the specimens was cured at a relative humility of 60–65%. Moreover, the foam stability of ULFC was promoted by the increased bubble confinement force with an incremental content of EVA. Also, an optimized air-void structure was observed in the sample containing synthetic C-S-H from X-CT due to its nucleation effect on the hydration of cement particles. From the energy consumption analysis in practical application, more than 50% energy consumed for heat supply was conserved in ULFC-embedded exterior wall.

Material Performance Tests of the Polymer-Cement Thin Spray-On Liner

Compared to conventional shotcrete, thin spray-on liner (TSL) has several advantages, including high efficiency, good adhesion, and low dust content. In order to study the underlying mechanism of polymers on thin spray-on liner materials, three polymers were tested in this study. They were mixed into the shotcrete materials to conduct viscosity, pulling, flexural strength, and compression tests. The correlations between the viscosity of the materials and their other mechanical properties were analyzed. The optimal mixing ratio obtained by the tests was at a polymer–cement ratio of 15%. The material had better mechanical properties overall when modified with a vinyl acetate-ethylene (VAE) copolymer emulsion. When a VAE emulsion was used to modify cement mortar, the results showed that the VAE modified mortar had the best viscosity performance of any of the tested emulsions at the same polymer–cement ratio. Because of the adhesion of the modified mortar on a marble wall, when the viscosity was 2,300–5,800 mPa·s, the slurry was evenly distributed and did not sag on the wall surface. The VAE emulsion was affected by its own viscosity, and the pull-out strength was also enhanced as the viscosity increased. As the viscosity of the VAE emulsion increased, its flexural strength initially increased and then decreased, whereas its compressive strength decreased linearly. This study provides a theoretical basis for the development and application of thin shotcrete materials.

The Impact of Ethylene Glycol on Droplet Growth Inhibition in Ethylene Vinyl Acetate Emulsions.

Pour point depressant (PPD) emulsion has been gaining attention in crude oil transportation owing to its potential to solve solidification issues that arise in cold climate environments. An emulsion system provides a wide range of temperature application that combines good shelf life and tunable thermal properties to tackle this problem. These features can be achieved by incorporating an antifreeze agent into the emulsion. One of the most commonly used antifreeze agents is ethylene glycol (EG). Hence, this study focuses on the thermal properties and droplet size growth of PPD emulsions that were aged in variable concentrations of EG solution. EG50 exhibited the lowest freezing temperature of −44 °C, while EG25 demonstrated the lowest vitrification temperature of −68.7 °C. The particle size of the emulsions underwent a significant reduction from 332.3 to 228.9 nm upon the stepwise EG concentration increment to EG50. However, when the concentration was increased to EG75, a slight increase in the emulsion particle size was observed with a recorded value of 237.8 nm. Thus, it is concluded that EG50 represents the optimum concentration for delivering the best freezing protection and producing a smaller droplet particle size.

Effects of Vinyl Acetate-Ethylene Emulsion on Setting Time and Mechanical Properties of Alkali-Activated Cementitious Materials

Effects of Vinyl Acetate-Ethylene Emulsion on Setting Time and Mechanical Properties of Alkali-Activated Cementitious Materials

Preparation of EVA Emulsion Self-Healing Capsules for Concrete and Evaluation of Healing Properties

The self-healing capsule was prepared with paraffin as wall and EVA (ethylene vinyl acetate) emulsion as core through melting condensation dispersion method. The morphology and chemical structure of capsules were characterized by optical microscope and Fourier transform infrared spectroscopy (FTIR). The influence of the stirring rate and emulsion to paraffin ratio on core content of the capsule was investigated. The flexural strength of mortar incorporated with capsules was tested to assess the effect of capsule on mechanical property. In addition, the compressive strength of the mortar was tested before and after self-healing to evaluate the healing efficiency of the capsule. The result showed that the highest core content of the capsule can reach up to 55% under the conditions that stirring rate was 400 rpm and emulsion to paraffin ratio was 1:1. FTIR and optical micrograph of the capsule indicated that the EVA emulsion was contained in paraffin successfully. The dosage of capsules had little effect on mechanical properties of mortar when it was less than 5 wt%. The healing efficiency of mortar for compressive strength was up to 99% at capsule content of 5 wt%, preload of 60% fmax and curing time of 7 days, which meant that the microcracks can be healed efficiently with the EVA emulsion capsule.

The impact of different antifreeze agents on the thermal properties of ethylene vinyl acetate emulsion

The application of pour point depressants in the form of emulsions provides an alternative to overcoming the problem of handling during applications in cold climate environments. The incorporation of antifreeze agents to these emulsions helps to improve their cold flow properties, without sacrificing much of the other properties. This study considered the effect of the incorporation of different antifreeze agents into ethylene vinyl acetate emulsions that are used as pour point depressants. The results obtained revealed that the ethylene glycol (EG) emulsion system gave the lowest freezing temperature of −45°C, while the propylene glycol emulsion system provided the lowest vitrification temperature of −64°C. The size of the particles in the emulsion was significantly reduced from 359.1 nm to 207.4 to 216.4 nm when an antifreeze agent was used in the emulsion compared to the control sample (pure water). As for the selection of the most suitable antifreeze for the emulsion system, the vitrification performance was a factor that was taken into consideration in the decision to select the EG system due to the fact that this system offered an adequate performance in terms of vitrification efficiency at around −59°C, although it was not as excellent as the vitrification efficiency portrayed in the propylene glycol system. However, the EG emulsion system was the most suitable system for the ethylene vinyl acetate emulsion, as it delivered the best protection against freezing and, at the same time, produced a decent particle size distribution.

An experimental study on infrared drying kinetics of an aqueous adhesive supported by polymer composite

The infrared drying of an aqueous polymer emulsion spread on a thin composite flat film is experimentally studied. The composite film is composed of polyamide fibers supported by a poly(vinyl fluoride) film. The aqueous polymer is an Ethylene Vinyl Acetate emulsion playing the role of adhesive. It is spread over the film with a low thickness, about one hundred micrometers. The aim of this work is to understand the effects of the presence of fibers on the drying of this thin-layer product. With this in mind, a specific laboratory set up composed of a near infrared heater is used in order to get the drying kinetics. First, incident heat fluxes received at the product surface and transmittances of materials (semi-transparent medium) are measured with an ad-hoc heat flux sensor. Then, many experiments are performed with and without fibers. For linking the final moisture content to the fibers thermal and hydric behavior, a microscopic analysis of the dried samples is investigated. This analysis is performed for two thicknesses of polymer corresponding to two covering rates of fibers.

Evaluation of Flow Ability Response in EVA Emulsion Preparation with Different Vinyl Acetate Percentage by Intrinsic Viscosity Measurement

Ethylene–vinyl acetate (EVA) copolymers were chosen for this work because they show different characteristics depending on their vinyl acetate (VA) percentage. EVA has a wide range of applications, including coating of photovoltaic cells and covering of tires and cables, as a consequence of the different varieties of the material depending on the VA percentage. To date, no study has been conducted yet to determine the relationship between VA percentage and the flow ability response of an emulsion. Previous studies commonly highlighted the effect of particle size and emulsifier concentration on the emulsion process, but none of these studies directly discussed the effect of VA percentage of an EVA copolymer on the flow ability response of an emulsion. In this study, correlation between polymer-interaction was studied through measurement of intrinsic viscosity

Effect of Vinyl Acetate-Ethylene(VAE) Emulsion on Coated Paper Properties

This study was focused on applying a new paper coating binder, vinyl acetate-ethylene(VAE) emulsion, with SB-latex and acrylic emulsion for paper coating application. VAE emulsion has a low monomer cost and is non-toxic chemical than conventional adhesive for paper coating such as styrene-butadiene latex( SB-latex) and acrylic emulsion. We conducted double coating in order to test VAE emulsion, which was applied on top surface only. The results showed that optical properties of the coated paper with VAE were similar with the SB-latex binders. In case of bonding strength, dry-pick of the coated paper with VAE showed almost same with other binders while wet-pick of the coated paper with VAE had a little bit lower strength than that with SB-latex.

Emulsion copolymerization of vinyl acetate-ethylene in high pressure reactor-characterization by inline FTIR spectroscopy

The objective of this research was to investigate the effect of temperature, pressure, initiator concentration and agitation rate, in ethylene-vinyl acetate emulsion copolymerization, on copolymer composition. The inline React-IR ATR system was used to monitor the reaction as well as to determine residual free vinyl acetate. Pressure, temperature and agitation rate have great influence on mass transfer of ethylene monomer to the reaction sites. The vinyl acetate was introduced in semi-batch mode as well as ethylene since the copolymerization was carried out under a constant pressure of ethylene. The higher temperature results in lower content of ethylene incorporated in copolymer. Increase of pressure has a direct effect on the ethylene content in the copolymers through increasing solubilization of ethylene monomer which in turn increases ethylene content in the copolymers. Copolymers of up to 15wt.% of ethylene content have been synthesized at an ethylene pressure of 30bar and a temperature of 75°C. Analytical methods, such as differential scanning calorimetry, nuclear magnetic resonance, thermogravimetric analysis, and infrared spectroscopy were used for characterization of copolymers.

Effect of the ethylene/vinyl acetate ratio of ethylene-vinyl acetate emulsion on the curing behavior of an emulsion polymer isocyanate adhesive for wood

We investigated the curing behavior of an emulsion polymer isocyanate adhesive for wood with different ethylene-vinyl acetate (EVA) emulsions, because it was found that the ethylene/vinyl acetate weight composition (E/VA ratio) of EVA could control the volume of gas emitted from the adhesive. EVA with higher VA content reduced the volume of gas emitted at the initial stage, which was caused by the extent of the reaction between the NCO groups and water. The reaction scheme of NCO could not be determined because the broad infrared (IR) absorptions due to CaCO3 and water masked the information of the NCO products in IR spectra. Examination of the degree of swelling suggested that the adhesive films stored for 3 weeks had the same degree of cross-linking structure in spite of the variation of EVA. This result was supported by IR spectroscopy, which showed the same amounts of NCO remained in these films. All the adhesives prepared in this study had satisfactory bond performance. The findings indicate that the E/VA ratio affects the curing behavior of the adhesive in the initial curing stage, whereas the cross-linking structure and the bond performance were independent of the E/VA ratio after storage for 3 weeks.

E V A エマルション

E V A エマルション

Continuous process for the production of vinyl acetate-ethylene emulsion copolymers

A lab-scale experimental program was conducted to determine the feasibility of producing vinyl acetate-ethylene (VAE) emulsion copolymers via a continuous reaction process, using poly(vinyl alcohol), or PVOH, as a protective colloid. A process configuration of multiple stirred-tanks in series was utilized. Comparisons were made between continuous and batch processes with regard to final-product properties. As expected, notable differences in the breadths of the particle-size distributions obtained via the two processes were observed. However, these differences did not appreciably alter product performance in tile-mortar applications (as measured by plywood-to-quarry-tile adhesive strengths). Additionally, for the continuous process, in-process and final-product samples were compared to determine how polymer properties varied with conversion.

Ethylene-Vinyl Acetate Emulsion Copolymerization: Monomer Partitioning and Preliminary Modelling

Steps towards the development of a mathematical model capable of describing ethylene-vinyl acetate emulsion copolymerization are presented here. In order to develop this model a thorough understand...

Reactor design considerations for gas—liquid emulsion polymerizations: the ethylene—vinyl acetate example

Gas—liquid emulsion polymerization presents certain problems which are not normally encountered during conventional emulsion polymerizations. The existence of a comonomer in the gas phase results in mass transfer limitations under cetain reaction conditions. Designed experiments have been used to study the ethylene-vinyl acetate emulsion process. These studies have identified the reaction conditions under which ethylene mass transfer limitations prevail. The present paper will focus on the results of a more detailed study of the reactor design itself. These results may be used to eliminate or reduce mass transfer limitations during ethylene-vinyl acetate emulsion polymerization. Results showing the effects of impeller design, sparging and agitation on the rate of polymerization, cumulative copolymer composition, particle size and number, and gel content are presented. As a result, one can identify the requirements, with respect to both reaction kinetics and reactor design, for the production of a high solids, homogeneous, high ethylene content copolymer. These observations, when coupled with the approach and the kinetic results presented earlier, provide a check-list of the requirements for successful scale-up of the process.