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AbstractThis work aims to add an epoxy-ended co-monomer to polyvinyl acetate (PVAc) emulsion adhesive-based wood adhesive to improve its resistance to heat and moisture. Here, glycidyl methacrylate (GMA), vinyl neodecanoate (VeoVa), and vinyl acetate (VAc) emulsion copolymers have been created and evaluated as wood adhesives. To prepare the emulsion-based adhesive samples, a polyvinyl alcohol (PVA) solution, aluminium chloride solution, preservatives, and a plasticizer are added. Following that, the poly(VAc–VeoVa–GMA) based adhesive sample is compared with the VAc, VeoVa, and methyl methacrylate (MMA) (poly(VAc-VeoVa-MMA)) co-polymer-based adhesive. Tensile shear strength of wood joints under dry and wet conditions was tested in compliance with EN 204-205 standard to assess the adhesives’ performance. The EN 14257 standard, which defines the shear stress of wood joints at 80 °C, was used to assess the heat resistance of the wood adhesives. Tests on the hardness of films confirmed the results of differential scanning calorimetry, which indicated that the glass transition temperature in the GMA-based adhesive was significantly higher than in the MMA-based adhesive. After 6 h of bonding, EN 204 shows that the tensile shear strength of a GMA-based adhesive increased by 15.56% in a dry environment, by 16.67% in a wet environment and 37.84% heat resistance when compared to a co-polymer-based adhesive based on MMA. The approach that was developed provides a simple and useful way of developing adhesives with enhanced heat, water, and bonding strength resistance. [ABSTRACT FROM AUTHOR]

Repercussion of overutilizing the fossil fuels and petrochemicals resulted in global warming and polluted environment. Hence, in the quest for alternative sources of raw materials for developing greener adhesives, renewable and natural polymers like polysaccharides have a huge potential. In particular, the traditional water-based emulsion wood adhesive employs colloid-like polyvinyl alcohol for stabilizing polyvinyl acetate (PVAc) emulsion. Researchers have recently become interested in utilizing xanthan gum, a naturally occurring polymer, in place of stabilizers. Here, the effects of xanthan gum addition as a stabilizer for PVAc homopolymer-based wood adhesives on performance properties were investigated. Emulsion polymerization technique was employed to synthesize xanthan gum stabilized PVAc homopolymer emulsion. Hence, the present work investigates the applicability of xanthan gum added 0.5% and 1% as a colloid for the synthesis of PVAc wood adhesives. Effect of the addition of xanthan gum as a colloid on physical, thermal, and mechanical properties was studied by viscosity, pH, contact angle measurement, differential scanning calorimetry (DSC), and pencil hardness test of films. Emulsions in varying xanthan gum concentrations were prepared, and a universal tensile machine was utilized to measure the shear strength of the PVAc homopolymers applied to wood. As the concentration of xanthan gum increased, the adhesives' viscosity increased. The drastic increase in water resistance with increasing xanthan gum content was confirmed by water contact angle measurement. The use of xanthan gum improved the PVAc films' hardness as well. When compared to a pristine sample, the tensile shear strength with 1 wt% of xanthan increased by 50% after 6 h of bonding in dry environment and by 61% in wet conditions (as per EN 204). The study's overall conclusion highlights the enhanced adhesive performance of xanthan gum stabilized PVAc emulsion-based adhesives. [ABSTRACT FROM AUTHOR]

Facade-rendering mortars and their painting layers are constantly exposed to weather and, therefore, influence the hygrothermal behavior of buildings. The characterization and assessment of coating materials is fundamental, seeking adequacy in their selection, especially regarding moisture and temperature. Considering the exposure conditions of the facades, risks of damages, such as mold development, may be avoided by an assertive evaluation and selection among different types of paints. In this context, this paper experimentally determined essential properties related to the hygrothermal behavior of painted mortars and simulated their resulting performance when applied on exposed facades in three Brazilian cities in distinct bioclimatic zones. Hygrothermal simulations were carried out using the software WUFI Pro 6.6. Six different types of paints were studied, among which satin acrylic paint (SAP) led to the lowest water vapor permeability and matte polyvinyl acetate (PVA), silicate (SIL), lime (LP), and hydrated lime with white glue (HLG) paints led to the highest. Matte acrylic paint (MAP), PVA, SIL, LP, and HLG had similar impacts on the vapor transmission of mortar renderings. In the simulations, reference (REF) and LP specimens generally resulted in the highest water contents throughout the year, followed by SIL and HLG. SAP led to the lowest water content and a more homogeneous curve than the other paints. Among the studied cities, Macapá, which has the highest annual normal rainfall sum and mean relative humidity, also had the highest mean total water content values over time, followed by Porto Alegre and Petrolina. In general, no probable mold development is expected. However, caution should be taken when extrapolating the results for climate or construction conditions different than the simulated ones. [ABSTRACT FROM AUTHOR]

Amongst water-based emulsion adhesives, polyvinyl acetate (PVAc) emulsion is majorly employed in the non-structural bonding of interior or exterior furniture and joinery industries. However, PVAc emulsion requires plasticizers, which inherently have challenges resulting in deteriorating thermal and mechanical properties. Hence, the present work focuses on formulating a plasticizer-free adhesive by copolymerizing vinyl acetate with butyl acrylate (BA). The physical, thermal, and mechanical properties of BA-incorporated adhesives were analyzed by viscosity, pH, water contact angle, pencil hardness test of films, and differential scanning calorimetry. Optimizing strategy by varying the content of BA was evaluated. The shear strength of the samples on the wood specimen was verified in dry conditions at various intervals, and in wet conditions as per EN 204 standard. The viscosity of the adhesives exhibited a positive shift, as the concentration BA increased. The hardness of PVAc films was also altered positively by the addition of BA. Water contact angle measurement unveiled the hydrophobic nature of BA incorporation. The performance of the newly formulated adhesive tested on dry conditions showed enhanced tensile shear strength, and the values were maximum for 1 wt. % BA sample. Tensile shear strength value measured at dry conditions after 7 d of drying displayed an increment of ∼5.5% on 1 wt. % BA sample, compared to pristine adhesive. Analysis at wet conditions also corroborated enhanced performance with BA incorporation. Hence by optimizing the content of BA, a new concept of PVAc emulsion adhesive without any plasticizer can be formulated, with enhanced water resistance and performance. [ABSTRACT FROM AUTHOR]

AbstractThe purpose of this work was to study the synthesis and characterization of an adhesive based on a glucose stabilized polyvinyl acetate homopolymer. Vinyl acetate monomer was stabilised onto liquid glucose using emulsion polymerization, and polymerization happened using potassium persulfate as an initiator. Here, the effects of adding liquid glucose as a stabiliser for adhesives were studied. Therefore, the current research examines whether liquid glucose, introduced at weight-based concentrations of 0.5% and 1.0%, is suitable as a colloid to produce PVAc adhesives for wood. By measuring viscosity, pH, contact angle, differential scanning calorimetry (DSC), and the pencil hardness test of films, the effect of adding liquid glucose as a colloid on physical, thermal, and mechanical properties was investigated. The shear strength of the PVAc homopolymers applied to wood using emulsions with varied liquid glucose concentrations was measured using a universal tensile machine. As the concentration of liquid glucose increased, the viscosity of the adhesives also considerably increased. Water resistance significantly rose when liquid glucose content increased, as was found by measuring the water contact angle. The use of liquid glucose increased the hardness of PVAc films, which was supported by the glass transition temperature. According to EN 204-205, the tensile shear strength with 1.0% of liquid glucose increased by 63.88% and 45.67%, respectively, over a pristine sample after 6 h of bonding in a dry environment and 24 h in a wet environment. The study’s overall conclusion highlights the higher adhesion capability of PVAc emulsion-based adhesives stabilized by liquid glucose. [ABSTRACT FROM AUTHOR]

Poly(vinyl chloride) undergoes dechlorination in the presence of triethylsilane (Et3SiH) and a catalytic amount of [Cp2Zr(NPh2)][CH3B(C6F5)3] (1 b) at 40–80 °C, with up to 91 % efficiency. Stoichiometric reactivity studies conducted on cyclohexyl chloride as a model suggest that 1 b dechlorinates PVC by initial chloride abstraction, followed by hydride transfer to the cationic PVC chain from Et3SiH. Consumer items such as pipe fitting, vinyl disc or electric cable insulation undergo either dechlorination or hydrosilylation of the carbonyl‐containing copolymer (polyvinyl acetate) or plasticizer (phthalate). [ABSTRACT FROM AUTHOR]

Significant variations in climate exist between the northern and southern regions of China, resulting in varying degrees of decay observed in wooden relics unearthed from different areas. The preservation of wooden cultural artifacts in humid environments is influenced by numerous factors including regional environmental conditions (such as temperature, humidity, and biological mold), and site structural characteristics, among others, making the conservation efforts more specialized and intricate. This study utilizes the example of the unearthed wet outer coffin wooden cultural relics from the Tomb of Marquis Yi of Zeng to demonstrate a method involving the use of polyvinyl acetate (PVAc) composite material for the reinforcement and protection of such artifacts. Through a comprehensive analysis of various analytical techniques including scanning electron microscopy, Fourier transform infrared spectroscopy (FT-IR), density increase rate, wood compression strength along the grain, hydrophobic property, and other micro and macro properties, it was determined that: The combination of PVAc and shellac as a reinforcement agent has been shown to enhance the mechanical properties of wooden cultural relics while also maintaining minimal color variation, increased biocompatibility, and durability. This method is particularly well-suited for fortifying and preserving damp wooden cultural relics that exhibit varying degrees of decay. The findings offer significant insights and potential avenues for further research on the preservation methods for large wooden cultural artifacts discovered in the middle and lower regions of the Yangtze River dating back to the Warring States Period. [ABSTRACT FROM AUTHOR]

In this study, quartz crystal microbalance (QCM) gas sensors, coated with electrospun polyvinyl acetate (PVAc) nanofibers, were employed to monitor the spoilage level of cultured Pacific white shrimp. The sensors exhibited a sensitivity range of 0.63 to 1.61 Hz/ppm when detecting trimethylamine vapor, a key biomarker for shrimp spoilage. Significant resonance frequency shifts were observed in the as‐prepared sensors when exposed to amine gases released by long‐stored shrimps. These shifts underline the significance of low‐temperature storage for shrimps. While color changes in the shrimps stored at ambient temperature (25 °C) become noticeable to the naked eye after 6 hours, the sensor detects sample deterioration much earlier, registering a prominent frequency shift (178 Hz) within only 3 hours of storage. This outcome suggests the potential of nanofiber‐coated QCM sensors as early‐stage food freshness indicators. [ABSTRACT FROM AUTHOR]

In this paper, we employ direct numerical simulations for studying the dynamics of two different, but miscible polymeric drops undergoing impact-driven coalescence with one of the drops making a head-on collision on an underlying drop. We consider two separate cases: (1) a PMMA (poly-methylmethacrylate) drop impacting a PVAc (polyvinyl acetate) drop and (2) a PVAc drop impacting a PMMA drop. For each case, three separate Weber numbers (We = 0, 1, 10) are considered. The interplay of finite impact speed and the specific wetting characteristic of the underlying drop leads to fascinating fluid dynamics. For example, for the case of the PMMA drop impacting on the PVAc drop, the strong wetting behavior of the PVAc drop ensures the impact-driven formation of an accelerated disk consisting of separate layers of PMMA and PVAc. Also, there is the generation of significant capillary waves at the drop–air interface, which in turn causes significant undulations of the drop–drop interface created due to such head-on collision. On the other hand, for the case of the PVAc drop impacting on the PMMA drop, the relatively weaker wetting behavior of the PMMA drop ensures that there is no formation of an accelerated disk; rather (for large We), the PVAc drop flows on top of the PMMA drop, forms a "canopy-like" structure, and wets the solid forming a transient core–shell structure (with PMMA core and PVAc shell). Our results raise the possibility of fabricating highly complicated multi-polymeric-material components by rapid curing of the drops in their post-impact configurations. [ABSTRACT FROM AUTHOR]

Amphiphilic cross-linked poly (vinyl alcohol-methyl methacrylate) (PVA-PMMA) copolymer nanoparticles (NPs) were prepared using a two-step process. Unlike other polymers, which are typically produced via direct polymerization, PVA is produced from the hydrolysis of polyvinyl acetate (PVAc). Therefore, in the first part of the project, copolymeric PVAc-PMMA NPs were prepared by using the radical emulsion polymerization method in different concentrations of BDOD (0–10% mol.) and water: methanol compositions. Conversion degree, morphology, particle size, and polymerization rate of non-agglomerated samples were evaluated. The optimal sample that synthesized in water: methanol % (90:10) as polymerization medium and 2.5% mol. crosslinker was hydrolyzed by 0.6 M NaOH solution. To confirm the hydrolysis reaction, FE-SEM, FT-IR, DLS, 1H NMR, and TGA tests were performed. The optimal sample was loaded by methotrexate (MTX), and drug release investigated at different times by UV-vis spectrophotometry. The sustained and pH-responsive profile of drug release in vitro was observed, and 47.24% of the drug was released at pH = 7.4 and 65.39% at pH = 5.8 after 96 h. Also, the MTT assay and dual-fluorescent acridine orange/propidium iodide assay showed that drug-loaded nanocarriers exhibited anticancer activity as applied to MCF-7 cells. [ABSTRACT FROM AUTHOR]

Real-time detection of formaldehyde in the atmosphere remains challenging. The available gaseous formaldehyde sensing methods offer limited sensitivity, selectivity, and robustness. We modified a quartz crystal microbalance (QCM) system for selective detection of formaldehyde in air. The QCM surface was functionalized with polyvinyl acetate (PVAc) nanofibers and doped with 2, 4, and 6 wt% aniline to improve the selectivity and sensitivity of the sensor. The chemical content and morphological structure of PVAc nanofibers doped with aniline were confirmed by Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive X-ray (EDX) spectroscopy, and scanning electron microscopy (SEM). The results showed that the modified QCM sensor had a sensitivity of 0.056 Hz ppm−1 with a response and recovery times of 200 s and 90 s, respectively. It gave limits of detection (LOD) and limit of quantification (LOQ) of 28 ppm and 96 ppm, respectively. Moreover, the modified QCM was selective towards formaldehyde compared to the other gases. The current workplace exposure limit (WEL) for formaldehyde is 2 ppm, with a time-weighted average over eight hours. Future work will focus on improving the reported QCM sensor to meet the required LOD for formaldehyde detection in the environment and industrial sites. [ABSTRACT FROM AUTHOR]

Maize starch, polyvinyl alcohol, glucose, and magnesium stearate are used as tablet excipients, acetylsalicylic acid as probe, polyvinyl acetate, and calcium alginate as protective membranes. By changing the proportions of the excipients, the nature and the thickness of the protective membrane, it was possible to optimize the formulation of a controlled release tablet. The mechanism and the kinetics of release of the active ingredient are evaluated using kinetic models: zero order, Higuchi, first order, Hixson–Crowell and Krosmeyer–Peppas. The representation of the released quantities using Krosmeyer–Peppas seems to be the most appropriate to describe the release mechanism (R2 ~ 1). The k and n values, Krosmeyer–Peppas, indicate that drug release is complex. The release rate of the AI is controlled by the erosion of the membrane and the relaxation of the chains of polymers constituting it. The solubility parameters (δ), according to Hansen, of the hydroxylated ingredients, predict compatibility and stability. [ABSTRACT FROM AUTHOR]

Wood wettability, the process of liquid interaction with wood surfaces, is influenced by wood surface chemistry, structure, ambient conditions, and temperature. Understanding how temperature impacts wood wettability is crucial for high-temperature manufacturing processes. In this study, the sessile drop method was employed to explore the dynamic wettability of Chinese fir wood using three different liquids (water, glycerol and polyvinyl acetate (PVAc)) across a range of temperatures (25, 40, 60 and 80 °C). By considering spreading, penetration and evaporation, we revealed that the dynamic wettability of Chinese fir was strongly dependent on temperature and the type of liquid. Temperature elevation enhances wettability, leading to reduced contact angles and increased penetration ratios. Water exhibited the highest wettability, followed by glycerol, with PVAc being the least wetting agent. Notably, after 180 s of wetting at 80 °C, the measured contact angles were 0° for water, 45° for glycerol, and 120° for PVAc. When accounting for evaporation, the penetration of water decreased from 57 % to 47 % (25 °C) and 100 % to 62 % (80 °C). The activation energies for the penetration of water and PVAc into Chinese fir exhibited variations, with values of 35.3 and 158.3 kJ/mol, respectively. These comprehensive wetting results, covering spreading, penetration and evaporation, provide valuable insights into wood–water and wood–adhesive interactions, particularly when exposed to high-temperature conditions. [ABSTRACT FROM AUTHOR]

In recent decades, due to high market demand and multiple environmental concerns, attention has been focused on the use of starch as renewable raw material for adhesives elaboration. Particularly, the origin and film-forming properties of Achira (Canna edulis) starch make it a potential representative for the development of bioadhesives. In this study, achira starch modified by acid hydrolysis and subsequent derivatization with urea was used to prepare adhesives for plywood substrates. For this purpose, the modified starch and polyvinyl alcohol (PVA) were used to prepare several formulations with different proportions of components. Afterwards, they were characterized in terms of physicochemical and mechanical properties. The formation of starch carbamates was confirmed not only by the results of nitrogen content, but also by infrared spectroscopy through the presence of N-H and C=O groups. On the other hand, viscosity increased with PVA content due to the interaction of hydroxyl groups, while starch had the opposite effect. Shear strength showed higher values at higher concentrations of PVA and starch. From the perspective of mechanical behavior, the results showed similarities with a commercial adhesive based on polyvinyl acetate (PVAc), as well as with other bio-based adhesives from studies conducted under comparable conditions. [ABSTRACT FROM AUTHOR]

Environmental considerations coupled with fossil fuel depletion encouraged research community to implement green protocol by partially or fully replacing petrochemicals. This is valid in case of adhesive research and development, where partial replacement of colloidal stabilizer, polyvinyl alcohol (PVA), is replaced by an abundant and sustainable material, corn starch (S). The work here investigates the effect of adding PVA and S blends formulated for polyvinyl acetate (PVAc)-white glue for wood adhesives. To enhance overall properties, boric acid, citric acid, glyoxal, and glutaraldehyde were employed as crosslinkers at a low concentration (0.1 wt.%). The presence of free hydroxy groups of PVA-S blend provides a site for the crosslinkers. Crosslinked blends are formulated with PVAc binder, plasticizer, and preservatives forming a wood adhesive. Various characterization techniques were employed for measuring physical and thermo-mechanical properties. Crosslinking was proved with dynamic mechanical analysis. Enhancement in performance properties was shown by the increase in tensile shear strength on bonded wood substrates and wet tack analysis. Tensile strength of bonded wood after 8 h. showed 16% increment for citric acid-incorporated sample, 13% for glutaraldehyde, 8% for boric acid, and ~ 7% for glyoxal crosslinked wood adhesive. Moreover, crosslinking consolidated polymer chains, which resulted in enhanced thermo-mechanical properties. Overall, the crosslinked samples showed better physical, mechanical, and thermal properties when compared to the non-crosslinked adhesive. Hence, this study can be a potential in the further development of sustainable white glue for wood bonding applications. [ABSTRACT FROM AUTHOR]

Since more than 3 years at Campus Kuchl of Salzburg University of Applied Sciences is a constant interest regarding Paulownia, a wood species that originates from Asia and was naturalized in European plantations in the last decade. The research started with the assessment of physical and mechanical properties of Paulownia tomentosa x elongata wood influenced by the stem height (different distances above soil) and the radial position from the pith to bark (cross-section spot), but also with the potential analysis of the sawn wood from three plantation sites in Europe as well as its suitability for the manufacture of solid wood panels (1 and 3 layer), plywood and particleboards. The results (based on Paulownia from Serbia) for the study of wood in the stem have shown that most properties are improved when the samples were taken from upper parts of the tree and from the near bark spot. The results (based on Paulownia from Spain, Bulgaria and Serbia) for the study of the sawn wood show that the mechanical-physical properties were significantly influenced by the plantation site (climate, soil etc.). The samples from Spain have the higher density and mechanical properties. The plantation wood from Bulgaria has the largest of annual ring width and therefore lower density resulting also in lower mechanical properties. The results for the study of edged glued solid wood panels (SWP), single-layered and three-layered made of Paulownia, both calibrated at a thickness of 19mm, were bonded with melamine-urea formaldehyde (MUF), polyurethane (PUR) and polyvinyl acetate (PVAc) resins. For the single-layered panels, the mechanical and physical properties did not differ significantly and are similar to those of massive Paulownia wood. For the three-layered panels, the adhesive application of PUR influenced positively all SWP properties. Considering the low density, these panels failed to achieve the performance of one-and singlelayered panels made of spruce. The results of these findings recommend Paulownia SWP as lightweight and sustainable core materials for sandwich structures for furniture, packaging industry, etc. Another aim of this research was to manufacture lightweight single-layered particleboard made of Paulownia plantation wood and to analyze the panel's properties at two levels of density, 300 and 400 kg/m² using urea-formaldehyde (UF) adhesive and high-frequency (HF) pressing technology. The physical and mechanical properties of the panels met at least the requirement for LP1 (light)particleboards for general purposes and use in dry conditions. As a low-density fast-growing tree, Paulownia could have a positive forecast for the European wood markets and a wide range of possible uses, especially in lightweight applications and can replace successfully expensive tropical species as Balsa. [ABSTRACT FROM AUTHOR]

The present study illustrates a simple and universally applicable method of synthesizing a new thermal stimuli-responsive thermoplastic shape memory polymer (SMP) and its composites through solvent casting method followed by the hot-pressing technique using polymers like polyvinyl acetate, polysulfone and polystyrene. The process parameters have been optimized to get a uniform film without any phase separation. Polyaniline (PANI), Al2O3, TiO2 and their combinations with PANI such as Al2O3–TiO2, Al2O3–PANI, and TiO2–PANI have been used as fillers to obtain the shape memory polymer composites (SMPCs). Under the thermal stimulus, the shape recovery rate of the SMPC containing Al2O3–PANI hybrid filler was faster, having a quick response time (150 s) compared to the response time of the neat SMP (210 s). Moreover, the SMP containing Al2O3 + TiO2 filler exhibited a higher Young's modulus (˃ 62%) compared to the neat SMP. The maximum stress of 37 MPa and 4.5% recoverable strain was observed in the SMP containing Al2O3 + TiO2 hybrid filler. Interestingly, no stored strain evolved upon cooling below Tg. The effect of physical aging on the mechanical and thermomechanical properties of SMP and its composites was studied. The synthesized SMP polymer is environmentally friendly and showed an excellent shape memory effect exhibiting a high Tg (~ 80 °C), self-healing property and good mechanical properties. Due to the multifunctional properties of the newly designed SMP and its composite, it may be a promising material for load-bearing applications. [ABSTRACT FROM AUTHOR]

This study was conducted to fabricate aluminum (Al) matrix composites reinforced with titanium oxide (TiO 2) continuous nanofibers to study their mechanical properties. For this aim, the solution containing polyvinyl acetate, dimethylacetamide, acetic acid, and titanium isopropoxide was electrospun over an Al layer at different times of 1, 3, 5, 10, and 20 min. After heat treatment at 500 °C, sheets containing nanofibers were sintered and connected together by the hot pressing at 625 °C. The characterizing of the nanofibers and composites was performed using Transmission electron microscope (TEM), Atomic force microscope (AFM), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) equipped with Energy-dispersive X-ray spectroscopy (EDS) analysis to evident the TiO 2 nanofibers morphology and their distribution in the Al matrix. The mechanical properties of composites produced with different electrospinning times were studied. The results showed that maximum yield and tensile strength (about 98% and 62% increase compared to Al matrix, respectively) and toughness were obtained in the composites with electrospinning times of 3 and 5 min. Additionally, it was found that the composites hardness was continuously increased by increasing the time of electrospinning (almost 44% more than the Al matrix). However, the tensile and toughness values were decreased in the composites with more increasing the amount of TiO 2 nanofibers at electrospinning times of about 10 min and 20 min. Fracture surface results showed that the presence of large aggregates, breakage of TiO 2 nanofibers, and weak bonding between the Al sheets were the effective factors in the decrease of mechanical properties of these composites at more electrospinning times. [ABSTRACT FROM AUTHOR]

This study deals with the contact erosion investigation and mechanical properties of both the un-stabilized and polyvinyl acetate (PVAc)-stabilized dispersive embankment layer. To this end, in addition to performing the specific dispersivity identification tests, i.e. pinhole and double hydrometer tests and contact erosion test for measuring the contact erosion parameters, a series of basic geotechnical tests was carried out. The microstructural changes with the aid of scanning electron microscopy (SEM) test and financial analysis were studied respectively to understand underlying mechanisms of stabilization and to estimate the economic benefits owing to PVAc addition. The results indicated that 2% PVAc content was the most effective proportion such that it decreased the dispersion potential, mass loss, and settlement of the dispersive soil by 69.6%, 70.5%, and 68.5% respectively, and at the same time, the strength of the samples increased by 107.4% only after 7 days of curing. The reaction between the polarity carboxyl hydrophilic group of PVAc and the hydroxyl group of the soil led to form the strong hydrogen bonds, and therefore, the structure stability and strength of the soil were enhanced. The formation of reticulated membrane structures and stronger bonds between soil particles, as documented by SEM images, testified to the excellent efficiency of PVAc in dispersive soil stabilization. Finally, the accuracy of available correlations between soil dispersivity and contact erosion parameters was examined, and then, the correlations were developed to cover a broad range of soils by using the results of this study. [ABSTRACT FROM AUTHOR]

Thermal modification of wood changes its chemical, physical, and structural properties, which may affect adhesive bondline quality and bonding performance. This research compared the effect of thermal modification on the adhesive bonding performance of poplar (Liriodendron tulipifera) wood. Samples were prepared from thermally modified and unmodified yellow poplar using one-component polyurethane (PUR) and polyvinyl acetate (PVA), as they are adhesives used in wood products. Microscopic properties of the bondlines were investigated to understand shear performance and durability. Adhesive line thickness, penetration, shear strength, and moisture durability were measured, and failure modes were recorded. Thermal modification negatively affected the wood and adhesive interaction by reducing penetration (31.2% in PUR and 29% in PVA), therefore creating a thicker adhesive line (70% in PUR and 2% in PVA) and consequently causing a significant reduction in the shear strength of both adhesive types (27% in PUR and 36% in PVA) compared with non-modified specimens. The PUR adhesive had higher shear strength than PVA by 2.7% in non-modified and 14% in thermally modified wood. [ABSTRACT FROM AUTHOR]

The temperature resistance of glued timber, which is crucial for glued wood construction, represents a significant assessment criterion. To gain insights into this aspect, this study utilized methods such as a shear strength test in accordance with EN 302-1:2013-06 under thermal loading (from 20 °C to 200 °C), and Differential Scanning Calorimetry (DSC) to determine the glass transition temperature (Tg). An increase in thermal load resulted in a decrease in shear strength and an increase in wood breakage. A hierarchy of adhesive groups was established based on strength performance and wood failure percentage (WFP) at 200 °C. Thermoset adhesives (MF: Melamine Formaldehyde, PRF: Phenol Resorcinol Formaldehyde) led the ranking, followed by elastomer adhesives (1C-PUR: One-Component Polyurethane, EPI: Emulsion Polymer Isocyanate), with thermoplastic adhesive (PVAc: Polyvinyl Acetate) last. Thermoset adhesives further cured under heat. PUR adhesives exhibited higher strength performance at 150 °C and lower temperatures. [ABSTRACT FROM AUTHOR]

Environmental remediation of xenobiotic pollutants is an important issue in industrialized society. Catalyst‐mediated pollutant photodegradation using solar light shows promising results. Titanium dioxide nanoparticles (TiO2 NPs) are a well‐known standard for mineralizing organic water pollutants. Its use as a sludge pointed out the need to support this photocatalyst to ease both its use and recovery. Polymers represent a viable solution because of their versatility, stability, and cheapness. The in situ radical bulk polymerization approach to the development of TiO2‐based thermoplastic nanocomposites for xenobiotic photodegradation enhances the photocatalytic performance of the semiconductor nanoparticles. The versatility and efficiency of these systems pave the way for their industrial applications as photocatalytic coatings for large‐scale surfaces. To shed light on the influences of the chemical nature of the polymer matrix on the photocatalytic efficiency of the nanosystems, polyvinyl acetate, polymethyl methacrylate, and polystyrene are investigated as supports for TiO2 NPs. The obtained TiO2‐containing nanocomposites are characterized by thermal analyses, UV‐vis, Raman, and X‐ray photoelectron spectroscopies, dynamic light scattering, and contact angle measurements. The photocatalytic activity of the nanosystems in the form of thin films is investigated against pollutants in water solutions, and shows clear differences in the photodegradation efficiency among the nanocomposites having different chemical natures of polymers. [ABSTRACT FROM AUTHOR]

Exploitation of fossil fuels has resulted in the declination of petrochemicals, which catalysed chemical industries to search for substitute raw material sources. The major raw materials used in wood adhesives, such as hydrocarbons like vinyl acetate (VAc) and polyvinyl alcohol (PVA), would be gradually replaced by renewable natural polymers. Starch, being a naturally abundant polymer, has been explored in wood adhesives. However, starch grafted polyvinyl acetate (PVAc) emulsion-based adhesive has inferior properties, such as poor water resistance, weak adhesion. Hence, to mitigate the issues, emulsion polymerization of acrylic acid (AA) as a co-monomer in starch stabilized PVAc-based wood adhesives has been investigated. Further, the sample is formulated with PVA, plasticizer, and preservatives. It was observed that AA provided sites for cross-linking the chains via reaction of the acid group at acidic conditions. Various analyses were further carried to study the effects of addition of AA and aluminium nitrate on stability and water-resistance of starch stabilized emulsion. Differential scanning calorimetry result showed a substantial increase in glass transition temperature, with the addition of starch in the copolymer emulsion, which is also confirmed in film hardness testing. Reaction between acid group in the copolymer chains, the free hydroxyls of starch and PVA, and the added aluminium nitrate resulted in a cross-linked network structure. The adhesion properties were evaluated by measuring the tensile shear strength of wood joints in dry and wet conditions. The cross-linked adhesive with starch showed improved water resistance, mechanical properties, and stability, unlike PVA stabilized cross-linked wood adhesives. [ABSTRACT FROM AUTHOR]

High-solid-content polystyrene and polyvinyl acetate dispersions of polymer particles with a 50 nm to 500 nm mean particle diameter and 12–55% (w/w) solid content have been produced via emulsion polymerization and characterized regarding their optical and physical properties. Both systems have been analyzed with common particle-size-measuring techniques like dynamic light scattering (DLS) and static light scattering (SLS) and compared to inline particle size distribution (PSD) measurements via photon density wave (PDW) spectroscopy in undiluted samples. It is shown that particle size measurements of undiluted polystyrene dispersions are in good agreement between analysis methods. However, for polyvinyl acetate particles, size determination is challenging due to bound water in the produced polymer. For the first time, water-swelling factors were determined via an iterative approach of PDW spectroscopy error (Χ2) minimization. It is shown that water-swollen particles can be analyzed in high-solid-content solutions and their physical properties can be assumed to determine the refractive index, density, and volume fraction in dispersion. It was found that assumed water swelling improved the reduced scattering coefficient fit by PDW spectroscopy by up to ten times and particle size determination was refined and enabled. Particle size analysis of the water-swollen particles agreed well with offline-based state-of-the-art techniques. [ABSTRACT FROM AUTHOR]

The effectiveness of two ways to reduce the vibration and sound emission of a high-pressure laminate plate has been investigated. It has been found that the inclusion of viscoelastic polymer polyvinyl acetate film in the laminate structure or constrained damping layer treatment based on polyvinyl acetate film and aluminum foil or plastic leads to a significant improvement in its vibroacoustic characteristics. The greatest reduction in vibration and sound emission was achieved by applying a coating with aluminum foil whose thickness was six times less than that of the damped laminate plate. [ABSTRACT FROM AUTHOR]

In the 1870s, dentures were one of the first products made with celluloid, the first semi-synthetic plastic. Despite the significance of denture development in the history of celluloid and plastics, the chemical characterization of dentures in museum collections has never been attempted. It is urgent to assess the extent of celluloid heritage in denture collections due to the high degradation risk that this material imposes. In this work, 21 dentures from the National Museum of American History and from the Dr. Samuel D. Harris National Museum of Dentistry were characterized using a multi-analytical methodology using handheld Raman, X-Ray fluorescence, and micro-Fourier transformed infrared spectroscopies. All dentures were successfully characterized: 12 are made of celluloid, 4 of vulcanized rubber, 2 of phenol–formaldehyde, 2 of polyvinyl chloride—polyvinyl acetate copolymer (PVC-PVAc) and 1 of polymethyl methacrylate (PMMA). The identification of the dentures' base materials allowed a better understanding of their history and posed new questions about their conservation. Handheld Raman was demonstrated as an excellent in-situ tool for the study of polymeric materials. [ABSTRACT FROM AUTHOR]

Rotation welding of wood dowels has the advantages of high bonding strength, fast processing speed and green environmental protection, and is suitable for jointing nodes in furniture and wood products. However, most wood friction welding specimens have poor water resistance where the welded joints are more likely to be damaged in wet environments, which greatly limits their wider application. Previous studies focused on using natural and green materials or methods to enhance bonding strength and water resistance of friction-welded joints. This paper reveals an innovative chemical pretreatment method to improve the water resistance of rotary friction welded joints by treating the substrate blocks or dowels with reagents that successively oxidize and sulfonate the wood, and spraying the dowels with Zinc acetate alcohol solution that has a lubricant effect, followed by friction welding. The findings show that both the dry bonding strength of friction welded joints and the wet bonding strength after impregnation with cold, hot, and boiling water of dowels pretreated with oxidation and sulfonation reactions were higher than those without pretreatment and significantly superior to the traditional polyvinyl acetate (PVAc) adhesive bonding. [ABSTRACT FROM AUTHOR]

Laminated veneer lumber (LVL) and reinforced laminated veneer lumber (RLVL) with carbon fiber were produced from heat-treated Scotch pine (Pinus sylvestris L.) wood using phenol formaldehyde (PF), polyvinyl acetate (PVAc), and polyurethane (PU) resins. Wood veneers were subjected to heat treatments at 150 °C, 170 °C, or 190 °C for 2 h before lamination. The effects of the reinforcement, heat treatment temperatures, and resins on the properties of the LVL and RLVL were analyzed. Density, equilibrium moisture content (EMC), modulus of rupture (MOR), and modulus of elasticity (MOE) were evaluated. The results showed that MOR and MOE values of solid wood and LVL specimens decreased with increasing treatment temperature. However, reinforcement with carbon fiber increased both MOR and MOE. In addition, the density values of the all RLVL specimens improved, and the EMC altered significantly for all test specimens. Compared to solid samples, the highest MOR values increased by approximately 21% in PF-RLVL samples. Similarly, the highest MOE values increased by 31% in PF-RLVL samples. In conclusion, carbon fiber, one of the most used fabric types in composites, could be utilized in the manufacture of reinforced LVL with heat-treated veneers. [ABSTRACT FROM AUTHOR]

Although conservation practices facilitate the preservation of museum collections, procedures used to stabilize ancient materials can alter their chemical and isotopic compositions, impacting the viability of such specimens for life history investigations. In this study, we applied two common consolidants – polyvinyl acetate (PVAc) and acrylic resin (Paraloid B-72™) – followed by two consolidant removal procedures to assess the impacts of these processes on the stable isotope compositions and structural characteristics of a series of subsamples taken from a representative archaeological faunal bone. We examined the collagen (δ 13C col and δ 15N col), structural carbonate (δ 13C sc and δ 18O sc), and phosphate (δ 18O p) isotopic compositions of the bone sample before and after consolidation to evaluate consolidant removal procedures. We also measured δ 13C sc , δ 18O sc , and structural characteristics before and after the pre-treatment commonly used to remove organic matter and secondary carbonate prior to isotopic analyses. Our results produced five main outcomes. First, an acetone treatment shorter than 48 h was sufficient to remove PVAc and acrylic resin from archaeological bone without altering the original δ 13C col and δ 15N col. Second, prolonged exposure (>48 h) to polar solvents during the consolidant removal procedure and collagen extraction modified collagen isotopic compositions, lowering its original δ 13C col by 0.3–0.4 ‰ and increasing its original δ 15N col by up to 0.9 ‰. Third, the consolidant application and removal procedures altered the original δ 13C sc and δ 18O sc. Fourth, the change in δ 18O sc was likely caused by the bleach (2% NaClO at 20 °C for 72 h)/acetic acid (0.1 M for 4 h at 20 °C) pre-treatment applied prior to isotopic analyses. Fifth, our results confirm and expand on previous studies reporting that δ 18O p remains unaltered after consolidant and solvent procedures. These outcomes provide a framework for obtaining reliable stable isotope compositions from archaeological bones that have been stabilized using consolidants. [ABSTRACT FROM AUTHOR]

Methyl methacrylate (MMA) material is considered to be a suitable material for repairing concrete crack, provided that its large volume shrinkage during polymerization is resolved. This study was dedicated to investigating the effect of low shrinkage additives polyvinyl acetate and styrene (PVAc + styrene) on properties of the repair material and further proposes the shrinkage reduction mechanism based on the data of FTIR spectra, DSC testing and SEM micrographs. The results showed that PVAc + styrene delayed the gel point during the polymerization, and the formation of two-phase structure and micropores compensated for the volume shrinkage of the material. When the proportion of PVAc + styrene was 12%, the volume shrinkage could be as low as 4.78%, and the shrinkage stress was reduced by 87.4%. PVAc + styrene improved the bending strength and fracture toughness of most ratios investigated in this study. When 12% PVAc + styrene was added, the 28 d flexural strength and fracture toughness of MMA-based repair material were 28.04 MPa and 92.18%, respectively. After long-term curing, the repair material added with 12% PVAc + styrene showed a good adhesion to the substrate, with a bonding strength greater than 4.1 MPa and the fracture surface appearing at the substrate after the bonding experiment. This work contributes to the obtaining of a MMA-based repair material with low shrinkage, while its viscosity and other properties also can meet the requirements for repairing microcracks. [ABSTRACT FROM AUTHOR]

Emulsion polymerization is the most applied method in the vinyl acetate monomer (VAM)–polyvinyl acetate (PVAc) process. However, the flammable property and unexpected bulk polymerization for the reactant and product may occur in the batch reactor or storage tank. VAM is reactive enough to decompose readily into free radicals and then, initiate the polymerization, which may contribute to heat accumulation due to the monomer, initiator, and solvent mixtures. This study attempts to analyze the exothermic reaction and compare the thermal runaway potential for various VAM solutions during PVAc polymerizations. Summarily, 50%, 70%, and 100% of VAM solutions reacting with 2,2'–azobis(2-methylpropionitrile) readily increase the self-heating rate with their concentration from adiabatic calorimetric tests. Furthermore, kinetic parameters of 50, 70, and 100 mass% VAM solutions were evaluated to elucidate the self-heating model associated with thermal analysis and to determine heat production mechanisms that are practical to proactive safety protocol for the PVAc emulsion process. [ABSTRACT FROM AUTHOR]

The different proportions of cobalt phosphate-containing nano-crystallite composite paints have been synthesized with CaCO3 and polyvinyl acetate adhesive. The abbreviations of these composite paints are CPM2, 2.50% Co3(PO4)2, CPM4, 4.49% Co3(PO4)2, and CPM6, 6.52% Co3(PO4)2. The specific heat capacity (Cp) of all these composite paints is found endothermic. The optimum value of Cp is observed for CPM2 composite paint among all paints. At 298 K, Cp of composite paints are 1.00 J g−1 K−1 for CPM2, 0.88 J g−1 K−1 for CPM4, and 0.81 J g−1 K−1 for CPM6. The Cp of Co3(PO4)2 is 0.94 J g−1 K−1 at 298 K. The ∼ 80% reflectance of polyvinyl acetate containing CaCO3 paint is reduced to ∼ 30% with the addition of 6.52% Co3(PO4)2. The composite paints are found semiconducting behavior due to band gap Eg 2.15 eV at λmax = 576 nm. The crystallite size of the CPM6 composite paint is 59.64 nm. [ABSTRACT FROM AUTHOR]

Various surface modification techniques have been developed to improve synthetic polymer surfaces' wetting, adhesion, and printing by adding various functional (polar) groups. UV irradiation has been proposed as a suitable procedure to achieve adequate surface modifications of such polymers, which can be of further use to bond many compounds of interest. The activation of the surface, the favourable wetting properties, and the increased micro tensile strength of the substrate after short-term UV irradiation suggest that such pretreatment can also improve the bonding of the wood-glue system. Thus, this study aims to determine the feasibility of UV irradiation for pretreatment of wood surfaces before gluing and to determine the properties of wooden glued joints prepared in this way. UV irradiation was used to modify variously machined pieces of beech wood (Fagus sylvatica L.) before gluing. Six sets of samples were prepared for each machining process. Samples prepared in this manner were exposed to irradiation on a UV line. Each radiation level had a certain number of passes through the UV line, the more passes, the stronger the irradiation. Thus, the radiation levels were as follows: 1, 5, 10, 20, and 50 passes. The dose (energy delivered on the wood surface) in one pass was 2.36 J/cm2. A wetting angle test with glue, a compressive shear strength test of lap joints, and designation of main failure patterns were used to evaluate the properties of wooden glued joints. Wetting angle test was performed according to EN 828, while the compressive shear strength test samples were prepared and tested following the ISO 6238 standard. The tests were conducted using a polyvinyl acetate adhesive. The study found that UV irradiation before gluing improved the bonding properties of variously machined wood. [ABSTRACT FROM AUTHOR]

The study developed and designed polyvinyl acetate (PVAc) foams using advanced freeze-drying technology, which exhibited good heat-insulating ability, flame retardancy, and mechanical properties. Different combinations of bleach kraft pulp, water-soluble chitosan, and zinc borate were used to reinforce the foams. The foams exhibited desirable compression and flexural properties, with compression strength and compression modulus ranging from 0.01 MPa to 0.08 MPa and 0.05 MPa to 0.29 MPa, respectively, while flexural strength and flexural modulus ranged from 0.12 MPa to 5.37 MPa and 9.86 MPa to 260,85 MPa, respectively. The use of zinc borate as a reinforcement resulted in improved thermal properties and reduced mass loss at 600°C by 20.69%. Thermal conductivity tests indicated that the foams had low thermal conductivity values ranging from 0.037 W/mK to 0.074 W/mK. The foams with zinc borate (60 g /L) and high molecular weight water-soluble chitosan (70 g /L) reinforcement exhibited high limiting oxygen index (LOI) of 28.72%. Overall, the results suggest that the PVAc foams could serve as a promising sustainable alternative in thermal insulation and construction fields. [ABSTRACT FROM AUTHOR]

Preparation techniques for producing films of individualized solution-dispersed nanoparticles (NPs) for optical spectroscopy are often technically challenging and tailored for a specific NP system. In this work, we present a rapid, easy, and economical technique for producing polyvinyl acetate (PVAc)-based NP-polymer films on the order of 100's of micrometers thick that exhibit high uniformity, low aggregation, excellent optical transparency, and low terahertz absorption. In addition, we find that these films are robust at cryogenic temperatures and have a high laser damage threshold of 0.3 TW cm−2, which make them suitable for pulsed laser measurements. We show that free-standing, flexible, PVAc films can incorporate both one-dimensional single-wall carbon nanotubes (SWCNTs) and zero-dimensional Au NPs. Using absorbance, Raman scattering, and photoluminescence excitation spectroscopy, we observe that SWCNT individualization is maintained, and minimized polymer strain imposed, when the nanotubes are transitioned from the solution to the polymer host. This PVAc-based polymer host presents researchers with a straightforward method for producing free-standing and flexible NP films with low aggregation. [ABSTRACT FROM AUTHOR]

Although grafting polymers on cellulose nanocrystals (CNCs) has attracted extensive attention due to their vast application prospects, the current grafting materials are mainly petroleum based polymers, which are unsustainable. Herein, by adding a trace amount of sodium citrate, a highly efficient grafting of bio-derived polyvinyl acetate (PVAc) onto the surface of CNCs was realized through classical free radical polymerization initiated by cerium ammonium nitrate (CAN) in an aqueous medium. The grafting yields of PVAc on the CNC surface climbed from 29.2% to 241.9% when the SC concentration was increased from 0 to 0.45 mmol L−1. The thus obtained CNC–PVAc can be almost completely degraded by soil burial for about 180 days, and therefore can be used as a new biodegradable nanofiller or polymer nanocomposite. Moreover, this strategy is generally applicable to various monomers and different surface groups of CNCs. [ABSTRACT FROM AUTHOR]

Currently, there is great interest in geopolymer composites as an alternative and environmentally friendly basis for compositions for restoring the facades of historical and modern buildings. Although the use of these compounds is much smaller than conventional concrete, replacing their main components with ecological geopolymer counterparts still has the potential to significantly reduce the carbon footprint and reduce the amount of greenhouse gas emitted into the atmosphere. The study aimed to obtain geopolymer concrete with improved physical, mechanical, and adhesive characteristics, designed to restore the finishing of building facades. Regulatory methods, chemical analysis, and scanning electron microscopy were applied. The most optimal dosages of additives of ceramic waste powder (PCW) and polyvinyl acetate (PVA) have been established, at which geopolymer concretes have the best characteristics: 20% PCW introduced into the geopolymer instead of a part of metakaolin, and 6% PVA. The combined use of PCW and PVA additives in optimal dosages provides the maximum increase in strength and physical characteristics. Compressive strength increased by up to 18%, bending strength increased by up to 17%, water absorption of geopolymer concretes decreased by up to 54%, and adhesion increased by up to 9%. The adhesion of the modified geopolymer composite is slightly better with a concrete base than with a ceramic one (up to 5%). Geopolymer concretes modified with PCW and PVA additives have a denser structure with fewer pores and microcracks. The developed compositions are applicable for the restoration of facades of buildings and structures. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Certain bamboo species have mechanical properties that are compatible with construction material. Despite this, their low shear strength, the presence of nodes in their culms, and their circular geometry inhibit the expansion of the use of this material as construction material. One technique that can solve these problems is glued laminated bamboo (GLB). Based on such findings, this paper aims to evaluate the physical and mechanical properties of glued laminated bamboo of the Dendrocalamus giganteus species. Two glues were used: resorcinolformaldehyde (PRF) and polyvinyl acetate (PVAc). The following physical and mechanical characterization tests were performed on glued laminated bamboo: water absorption, density, compression parallel to fiber direction, tension parallel to fiber direction, shear parallel to the glue layer, shear parallel to fiber direction, and bending. The results, analyzed using statistical models, showed that the GLB has physical and mechanical properties comparable to those of hardwoods. [ABSTRACT FROM AUTHOR]

branches, acacia, polyvinyl acetate, particleboard, physical properties, mechanical properties The quality of particleboard made from broad-leaved acacia branches and PVAc adhesive was investigated. A non-factorial completely randomized design (CRD) with adhesive contents of 10%, 15%, and 20% was employed. The parameters for testing physical properties included moisture content, density, water absorption, and thickness swelling. The parameters for testing the mechanical properties were modulus of elasticity, modulus of rupture, internal bonding, and screw withdrawal resistance. The results indicates that the concentration of PVAc adhesive has a significant effect on both physical and mechanical properties of the fabricated particleboards. The LSD further test indicates that particleboard with 20% adhesive content has the highest value in strength tests and meets the Indonesian National Standard (Standard Nasional Indonesia/SNI) 032105-2006. It is suitable for non-structural indoor (interior) element. [ABSTRACT FROM AUTHOR]

Adhesives for gluing thermally modified wood were analyzed. The methods for conducting experimental studies to determine the strength of adhesive joints of thermally modified ash wood and unmodified pine wood, using polyvinyl acetate (PVAc)-based adhesives of durability class D4 were described. According to the results of experimental studies based on the proposed methodology, it was established that the strength of adhesive joints of thermally modified ash wood and unmodified pine wood stretched along the fibers after the first stage of testing is 6.21 MPa, after the second stage 4.56 MPa, and after the third stage 3.90 MPa. The average strength of the adhesive joints of the control specimens is 7.12 MPa. According to the obtained research results, the nature of destruction of the adhesive joints of thermally modified ash wood and unmodified pine wood was determined depending on the test stage. The greatest destruction occurred on the adhesive line, and the least on the pine wood. It was assumed theoretically that during the thermal modification of ash wood, hemicellulose decomposes and acetic acid is released, leading to the formation of furfural, which impairs wood surface wetting and affects the adhesive strength of PVA-based adhesive joints. [ABSTRACT FROM AUTHOR]

The research results of properties of self-compacting fine-grained ash-cement mixes and concretes containing the polyfunctional modifier are presented. With the optimal composition of such a modifier, which includes polyvinyl acetate dispersion and superplasticizer, it becomes possible to improve self-compacting concrete's properties significantly. [ABSTRACT FROM AUTHOR]