Polyvinyl Acetate Adhesives Research Articles

Adhesive paperboard connections in architectural applications: modelling, characterization, and performance assessment

ABSTRACT Paper-based elements have been researched as cheap and pro-ecological building materials for several decades and bonding is the most widely used method of joining them. However, adhesives may increase the cost, weight, and environmental impact of the component. The suitability of different adhesive types for paper-based building component bonding has not yet been researched. This work evaluates the properties of six types of commercially available adhesives – polyvinyl acetate, dextrin, and synthetic rubber. The results of single-lap tensile tests served as the input for a Goland–Reissner model of adhesive stresses. The elastic properties of the adhesives were estimated based on tensile test results – Shear modulus ranging from 0.626 to 1.097 MPa and Young’s modulus from 0.703 to 2.940 MPa. The modelled shear strength ranged from 1.1922 to 1.6115 MPa and the peel strength from 0.3265 to 0.5894 MPa. Recommendations for adhesive use in paper-based building elements are formulated. Polyvinyl acetate adhesives may be recommended for general use; however, the use of starch/dextrin adhesives should not be neglected. The presented work successfully demonstrates a methodology to obtain properties of adhesives for the mechanical assessment of the bonds from simple tensile tests of single-lap joints.

Preparation and Characterization of Particleboard Made from Industrial-Type Wood Particles and Discarded Duck Feathers

Global poultry waste production is substantial, with billions of poultry raised annually for meat and egg production, resulting in significant feather waste. Conventional poultry waste disposal methods are restricted due to environmental concerns. Meanwhile, wood-composite panel industries face raw material shortages, emphasizing the need for sustainable, renewable fiber sources. In this study, in the core layer of panels, wood particles were replaced with 5 wt% clean duck feathers without pretreatment to take advantage of feather attributes like hydrophobicity, thermal insulation, and sound damping as an alternative construction material. Three adhesives—urea-formaldehyde (UF), polymeric 4,4′-diphenylmethane diisocyanate (pMDI), and polyvinyl acetate (PVAc)—were examined for resin–feather compatibility. The control panels in this study were identical but wood was not replaced with feathers. The results revealed that wood–feather particleboard with pMDI and PVAc resins meets the requirements of the relevant standard for P2 boards (where applicable) concerning their modulus of rupture (MOR: 11 N·mm−2), modulus of elasticity (MOE: 1600 N·mm−2), internal bond (IB: 0.35 N·mm−2), and screw withdrawal resistance (SWR). However, those produced with UF resin did not meet the standards for IB and MOE. Furthermore, the physical properties showed similar water resistance and thickness swelling to control panels with pMDI. Notably, substituting 5 wt% wood with feathers improved thermal insulation by approximately 10% for UF and pMDI resins. Additionally, particleboard with feathers demonstrated improved sound absorption at high frequencies, ranging from 2500 to 500 Hz, particularly with pMDI resin, approaching Class B classification according to EN ISO 11654:1997. This study identifies the higher compatibility of pMDI over PVAc and UF adhesives for feather-based composite materials in construction applications.

An eco‐friendly and high shear strength adhesive from catechol‐modified polyethyleneimine

AbstractConventional adhesives often emit volatile organic compounds (VOCs), which have a negative impact on human health. In this paper, an environmentally‐friendly supramolecular adhesive PD which has high adhesive and low VOCs emission is prepared by the reaction between polyethyleneimine (PEI) and 3,4‐dihydroxybenzaldehyde (DBA). PD containing abundant catechol groups exhibit excellent adhesion to wood substrates and is able to reach a maximum shear strength of 5.20 ± 0.39 MPa. One factor is attributed to multiple reactions between PEI, and DBA and oxidation of DBA. These reactions construct a complex three‐dimensional cross‐linked structure which is very helpful to improve the bonding performance of the adhesive. Another reason refers to the fact that a large number of catechol groups in PD can form a lot of hydrogen bonds with the amino group in PEI and the hydroxyl group in the wood substrate. These hydrogen bonds play an important role in enhancing shear strength. PD adhesives have a stronger bond strength than commercial chloroprene rubber (CR, Pattex‐PXL) and polyvinyl acetate adhesives (PVAc, JUJU‐8708) and have lower emissions of VOCs. As an environmentally‐friendly adhesive for wood‐based substrates, this adhesive may have potential applications in the wood processing industry.

Variation Of Bamboo and Adhesive Types on Physical And Mechanical Properties Of Particle Board

Bamboo can be used as a material in the manufacture of particleboard. The purpose of this study was to examine the effect of various types of bamboo and their adhesion on the physical and mechanical properties of particleboard. The study used a factorial completely randomized design with three repetitions. Particleboard made using cold pressing made of bamboo betung (Dendrocalamus asper Schult.), bamboo apus (Gigantochloa apus Kurz), bamboo ori (Bambusa arundinacea Retz), and Urea Formaldehyde and Polyvinyl Acetate adhesives. The particle size used was through eight meshes with an adhesive concentration of 20% and a target board density of 1 gram/cm³. Board testing using SNI 03-2105-2006, correlation analysis, and regression to see the relationship between variables. The resulting particleboard has a density between 0.5 – 0.69 gram/cm³, air content between 12.7% - 15.2%, thickness expansion between 2.2% - 17.55%, MOE 1.963 - 4.898 kg/ cm², MOR 4.89 – 9.36 kg/cm². The type of bamboo has no significant effect on density, moisture content, MOE, and MOR of particleboard. The type of adhesive has a significant effect on the density, MOE, and MOR of the particleboard. The interaction between the type of bamboo and the type of adhesive has a significant effect on the thickness development of the particleboard.

TECHNOLOGY OF PARTICLEBOARD’S PREPARATION BY COLD PRESSING AFTER HOT MAT COMPRESSION

The article describes amethod of preparing particleboards (PB) from fresh and recycled chips by anew technology of cold pressing after hot compression of the mat according to PCT/SK2023/000007 (ÚPV SR, 13.06.2023) using polyvinyl acetate (PVAc) glue. Forcomparison, the experiment was also carried out using urea formaldehyde (UF) glue and their mutual combination. The new method shortens hot pressing, or causes reduction of pressing temperatures, while the prepared PB released from pressure no longer spring and cure over time. The curing kinetics of both PVAc and UF adhesives were described by monitoring the flexural strength and modulus of elasticity of PB as a function of time after release of pressure.Modeling of the PB pressing process based on PVAc glue, which consists of overheating the pressed cross-section of the board to 90°Cand its subsequent cooling to a temperature when the board is already stable, i.e. below a temperature of 70°C, was carried out using of a hot and cold press, while the pressing cycle lasted 140 s. Shortening the pressing cycle to 100 s was achieved by applying the glue to the chips already preheated to 92°C.Laboratory tests have confirmed that the mechanical properties of PB are in accordance with the requirements of EN 312/3 for chipboards for interior conditions, including furniture, for use in dry environments.

Foaming the polyvinyl acetate (PVA) and poly urethane (PU) wood adhesive and characterization

In this study, polyvinyl acetate (PVA) and polyurethane (PU) wood adhesives were foamed. It was aimed to achieve adhesive savings by allowing the adhesives to cover a larger surface area through foaming. Egg white (EW), wheat flour (WF), and Sodium Lauretha Sulfate (SLES) were used as foaming agents for the adhesives. The foaming agents were mechanically mixed within a glass container to foaming, and then adhesive was added to the foam and mixed again using a mechanical mixer. The characterization of the foamed adhesives was conducted through viscosity and perpendicular adhesive strength (PB)analyses according to TSE standards. According to the analysis results, it has been determined that foaming PU adhesive with foaming agents is more successful. The foam stability of PVA adhesive was significantly low, as the foam completely deflated after approximately 30 minutes. The addition of EW and WF to PU resulted in a more solid and rigid foam. Thanks to this characteristic, PU foams can be used in the production of wood sandwich panels. According to the study results, further research is anticipated to be conducted on the foaming of PU adhesive, and the obtained foams are predicted to be used in the furniture industry for panel production.

Prediction of the Strength of Oakwood Adhesive Joints Bonded with Thermoplastic Polyvinyl Acetate Adhesives

Among the several kinds of thermoplastic adhesives, structured and non-structured polyvinyl acetate (PVA) adhesives have a rather wide application and are used currently for forming adhesive joints from different wood species, especially oakwood. To ensure proper conditions of oakwood adhesive joints use, it is important to have fast and accurate methods of predicting their strength and durability. The strength changes of the oakwood adhesive joints bonded with structured and non-structured PVA adhesives have been investigated by conducting long-term experiments. Based on the generalization of experimental data and theoretical predictions regarding the mechanism of the adhesive seam formation, equations that allow calculating theoretically the strength of oakwood adhesive joints bonded with non-structured and structured PVA adhesives have been proposed. The pro-posed equations reproduce experimental data with suffi-cient accuracy of ±3.5 % within the temperature range from 251 K to 306 K and humidity range from 40 % to 100 %, and therefore, are recommended for practical use.

Analysis of Bonding Mechanisms of Various Implants and Adhesives in Laminated Oak-Wood Elements.

This study analysed the bonding mechanisms and strength between wood and non-wood implants in producing laminated oak-wood beams. The suitability of different types of adhesives, namely for load-bearing and general purpose, was also analysed. Three different types of non-wood implants-carbon fibres, glass fibres, and aluminium were glued with epoxy resin (ER), thermoplastic 1-k polyurethane adhesives (PUR), structural polyurethane adhesives (PUR 2 and PUR 3), and polyvinyl acetate (PVAc) adhesives and bonds were tested for shear strength (SS) according to ISO 6238:2018. Results of the bond quality expressed as the ultimate load to failure and displacement were recorded using the universal mechanical testing machine in combination with the digital image correlation (DIC) method. Before the shear test, all the samples were conditioned in dry and wet climatic conditions. Test results indicated that the application of PUR adhesives for bonding carbon and glass fibres with oak wood could sufficiently replace two-component ER, which is generally recommended for such purposes but is very challenging to utilise in industrial conditions. PVAc adhesives proved efficient only for combination with AL implants and in dry conditions. Aluminium sheets were shown to require surface pre-treatment, such as sanding and degreasing or a different type of adhesive to achieve sufficient adhesion.

Importance of Dynamic Mechanical Analysis to Predict Performance of the Polyvinyl Acetate Wood Adhesives in Summer Season

Conventionally available Polyvinyl acetate (PVAc) wood glues are polyvinyl alcohol (PVA) stabilized, with drawbacks like poor strength at high humidity, poor strength at high temperature and workability at low-temperature. PVAc is non-resistant to high humidity, and if such adhesive bonds are exploited in a highly humid environment, its strength substantially decreases. Sufficiently water-resistant adhesive bonds are achieved by modifying PVAc dispersion with special chemicals like acrylic acid (AA) and N-methylol acrylamide (NMA) as a co-monomer, Silanes, and ethylene modified PVA. The Lewis acids like aluminium chloride and aluminium nitrate are used as cross-linkers. So PVAc adhesives are classified as reactive and non-reactive glue. Application of non-reactive D1 (as per EN 204-205) and reactive D2 and D3 (as per EN 204-205) adhesives for bonding laminate on plywood is a regular practice in the Indian market. In summer time, Crack formation was seen in laminate bonded with reactive D2 and D3 adhesives in regions where the room temperature was above 45°C. However, if the same laminate substrates were bonded with non-reactive D1, no cracks were seen. To analyse the above phenomenon, we have done Dynamic mechanical analysis of non-reactive D1, reactive D2 and D3 adhesive.

Application of Formaldehyde Free Adhesive in Composite Floor

With the enhancement of consumers' concept of "health and environmental protection", the requirements for the living environment are higher and higher, and the quality of home decoration materials has attracted much attention. The green adhesive without formaldehyde has become a research and application hotspot in recent years, and has been more and more widely used in the composite floor industry. Composite floor is an indispensable building material with large application area in residential decoration. The selection and use of adhesives directly determine the environmental protection grade of composite floor. Biomass adhesives, polyurethane adhesives and thermoplastic resin adhesives represented by soybean adhesives are the three types of aldehyde free adhesives with the greatest development potential in composite floor industry at present. This paper reviews the application of aldehyde free adhesives such as polyurethane (including isocyanate) adhesives, waterborne polymer isocyanate adhesives, polyethylene films, soybean protein adhesives and polyvinyl acetate adhesives in solid wood composite floors and paper impregnated laminated wood floors (laminate floor), bamboo floor and other common composite floors, discusses the existing problems, and looks forward to the main research and development direction in the future.

Effect of Sanding and Plasma Treatment of 3D-Printed Parts on Bonding to Wood with PVAc Adhesive.

Additive manufacturing is becoming increasingly important for manufacturing end products, not just prototyping. However, the size of 3D-printed products is limited due to available printer sizes and other technological limitations. For example, making furniture from 3D-printed parts and wooden elements requires adequate adhesive joints. Since materials for 3D printing usually do not bond very well with adhesives designed for woodworking, they require special surface preparation to improve adhesion. In this study, fused deposition modelling (FDM) 3D-printed parts made of polylactic acid (PLA), polylactic acid with wood flour additive (Wood-PLA), and acrylonitrile-butadiene-styrene (ABS) polymers were bonded to wood with polyvinyl acetate (PVAc) adhesive. The surfaces of the samples were bonded as either non-treated, sanded, plasma treated, or sanded and plasma treated to evaluate the effect of each surface preparation on the bondability of the 3D-printed surfaces. Different surface preparations affected the bond shear strength in different ways. The plasma treatment significantly reduced water contact angles on all tested printing materials and increased the bond tensile shear strength of the adhesive used. The increase in bond strength was highest for the surfaces that had been both sanded and plasma treated. The highest increase was found for the ABS material (untreated 0.05 MPa; sanded and plasma treated 4.83 MPa) followed by Wood-PLA (from 0.45 MPa to 3.96 MPa) and PLA (from 0.55 MPa to 3.72 MPa). Analysis with a scanning electron microscope showed the smooth surfaces of the 3D-printed parts, which became rougher with sanding with more protruded particles, but plasma treatment partially melted the surface structures on the thermoplastic polymer surfaces.

Вплив навантажень на формостійкість тришарової паркетної дошки

Досліджено вплив навантажень на формостійкість тришарової паркетної дошки, склеєної термопластичними полівінілацетатними клеями, залежно від їх величини під час експлуатації. На основі побудованої математичної моделі для прогнозування формостійкості тришарової паркетної дошки залежно від дії зовнішніх факторів під час експлуатації з використанням імітаційного моделювання досліджено пружно-деформаційний стан тришарової паркетної дошки, склеєної термопластичними полівілацетатними клеями. Побудовано графічні залежності радіальних та тангентальних напружень у тришаровій паркетній дошці і проаналізовано їх вплив на паркетну дошку під час експлуатації залежно від навантажень. Під час математичного та імітаційного моделювання тришарову паркетну дошку розглянуто як клейову конструкцію, що складається із трьох шарів, а саме: верхнього, середнього та нижнього, склеєних між собою термопластичними полівінілацетатними клеями із ступенем навантаження 3D. Кожний шар конструкції виготовлений із різних матеріалів, а саме: верхній шар – із твердолистяної породи деревини дуба, середній – із хвойної породи сосни та нижній – із фанери. Оскільки для матеріалу, з якого виготовлена конструкція, характерні різні фізико-механічні властивості, то відповідно, це матиме вплив на пружно-деформаційні процеси тришарової паркетної дошки під час навантажень та визначатиме формостійкість виробу. Встановлено, що за дії на тришарову паркетну дошку, склеєну термопластичними полівінілацетатними клеми, фізичних навантажень, тангентальні напруження будуть зростати у середньому шару, який виготовлений із ламелей деревини сосни та розміщений перпендикулярно до верхнього лицевого та нижнього основного шару. Мінімальне значення тангентальних напружень спостерігається у середині верхнього лицевого та нижнього шарів. Такий розподіл навантажень у тришаровій конструкції паркетної дошки, досягається завдяки нижньому шару, який виготовлений із фанери, та еластичності клейового з'єднання, яке формується термопластичними полівінілацетатними клеями. Це дає змогу компенсувати напруження у внутрішньому шарі тришарової паркетної дошки під час її експлуатації, цим самим покращити її формостійкість.

Development of polyvinyl acetate adhesive bond strength when gluing veneer

This article presents the development of the shear strength of two polyvinyl acetate (PVAc) adhesives: Mekol D3 and Mekol SPECIAL when bonding veneer depending on pressing time. Besides testing the strength of the adhesive bond after hot pressing, we also investigated the effect of cooling on the final strength of PVAc adhesive bonds. The shear strength development of the PVAc adhesive bond during hot pressing was determined using an Automated Bonding Evaluation System (ABES). The pressing temperature was constant and was 80 °C, while the pressing time was extended from 30 to 300 seconds in 30-second intervals. The effect of cooling on the final strength of the PVAc adhesive bond was determined after cooling times of 5 and 30 seconds. Based on the investigations, we found that the shear strength of PVAc adhesive bonds increased with the pressing time and approached a constant value after a certain time. We found significant differences in the strength of adhesive bonds glued with Mekol D3 and Mekol SPECIAL and a statistically significant effect of cooling on the strength of the adhesive bonds.

Bonding of Selected Hardwoods with PVAc Adhesive

The bonding of wood with assembly adhesives is crucial for manufacturing wood composites, such as solid wood panels, glulam, furniture parts, and sport and musical instruments. This work investigates 13 hardwoods—bangkirai, beech, black locust, bubinga, ipé, iroko, maçaranduba, meranti, oak, palisander, sapelli, wengé and zebrano—and analyzes the impact of their selected structural and physical characteristics (e.g., the density, cold water extract, pH value, roughness, and wettability) on the adhesion strength with the polyvinyl acetate (PVAc) adhesive Multibond SK8. The adhesion strength of the bonded hardwoods, determined by the standard EN 205, ranged in the dry state from 9.5 MPa to 17.2 MPa, from 0.6 MPa to 2.6 MPa in the wet state, and from 8.5 MPa to 19.2 MPa in the reconditioned state. The adhesion strength in the dry state of the bonded hardwoods was not influenced by their cold water extracts, pH values, or roughness parallel with the grain. On the contrary, the adhesion strength was significantly with positive tendency influenced by their higher densities, lower roughness parameters perpendicular to the grain, and lower water contact angles.

Improved strength properties of LVL glued using PVAc adhesives with physical treatment-based Rubberwood (Hevea brasiliensis)

Abstract The properties of the laminated veneer lumber (LVL) composed of the boiled veneer of Rubberwood (Hevea brasiliensis) using polyvinyl acetate (PVAc) adhesives in various cold-pressing time and various conditioned time with loaded and unloaded were studied. Five-ply LVL was produced by boiling veneer at 100°C for 90 min as pretreatment and cold-pressing time at 12 kgf cm−2 for 1.5, 6, 18, and 24 h then conditioned at 20°C and 65% relative humidity (RH) with loaded (12 kgf cm−2) and unloaded for 7 days as physical treatment. Especially for the delamination test, the specimens were immersed at 70 ± 3°C for 2 h and dried in the oven at 60 ± 3°C for 24 h; then, the specimens were solidified at room temperature (20°C and 65% RH) with loaded (12 kgf cm−2) and unloaded for 7, 10, 12, and 14 days. To determine the performance of LVL, the density, moisture content (MC), delamination, modulus of elasticity (MOE), modulus of rupture (MOR), horizontal shear strength, and formaldehyde emission tests were conducted according to the Japanese Agricultural Standard (JAS 2008) for structural LVL. The MOE and MOR values were significantly influenced by the physical treatment, however, neither to horizontal shear strength nor to formaldehyde emission. The best performance of LVL has resulted from unloaded LVL with cold-pressed time for 18 h; the MOE and MOR values were 9,345.05 ± 141.61 N mm−2 and 80.67 ± 1.77 N mm−2, respectively. The best value of the horizontal shear strength was obtained from the LVL with 18 h cold-pressing time and conditioned with loaded (13.10 ± 1.47 N mm−2) and unloaded (12.23 ± 1.36 N mm−2). The percentage of delamination values decreased with an increase in the cold-pressing time and conditioning time. The lowest value of delamination (19.06%) was obtained from the LVL with 24 h cold-pressing time and conditioned with loaded for 14 days. Except the delamination test, all other properties fulfilled the JAS.

Micro- and Nanofibrillated Cellulose (MNFC) from Pineapple (Ananas comosus) Stems and Their Application on Polyvinyl Acetate (PVAc) and Urea-Formaldehyde (UF) Wood Adhesives

Micro- and nanofibrillated cellulose (MNFC) was extracted from pineapple stems by acid hydrolysis, then characterized and tested in two concentrations (0.5 and 1.0 wt%) in polyvinyl acetate (PVAc) and urea-formaldehyde (UF) adhesives. The modified adhesives were used to glue three tropical wood species (Vochysia ferruginea,Cordia alliodora, andGmelina arborea), and their corresponding bond strength resistance was determined. MNFC and the correspondent adhesives were characterized by TGA, FTIR, SEM, TEM, AFM, and viscosity determination. The TGA analysis of MNFC showed three decomposition reactions. The SEM, TEM, and AFM evaluations demonstrated the presence of micro- and nanosized dimensions of particles after the acid hydrolysis of pineapple stems. Adding 1 wt% MNFC to PVAc and UF adhesives increased their thermal stability in similar manner. Viscosity diminished in both modified adhesives with MNFC; however, this reduction did not affect the adhesion properties in the tropical wood tested. MNFC added to PVAc and UF adhesives improved shear strength (SS) of the glue line in the three tropical species tested. The highest SS increase was obtained when adding 0.5 wt% MNFC to PVAc inV. ferruginea, and 1 wt% MNFC concentration in the case ofC. alliodoraandG. arborea. In the case of UF adhesives, the application of 1 wt% MNFC produced significant differences in SS for the three tropical species studied.

НАТУРНОЕ ИССЛЕДОВАНИЕ ПРОЧНОСТИ СКЛЕИВАНИЯ МАССИВНОЙ ДРЕВЕСИНЫ СОВРЕМЕННЫМИ КЛЕЯМИ ПРИ ЭКСПЛУАТАЦИИ В РАЗЛИЧНЫХ УСЛОВИЯХ

Abstract
 Glues are widely used to connect various materials, especially since in some cases other options for combining materials are not suitable. The paper deals with the bonding of solid hardwood with modern adhesive materials. Currently, a large group of adhesives of various brands from Russian and foreign manufacturers is presented on the market. In the woodworking industry, adhesives are used in the carpentry and furniture, manufacturing, in wooden house-building, in the production of finishing materials, etc., which are operated outside and inside the premises in constant and variable humidity conditions. Therefore, the correct choice of adhesives plays an important role both for the manufacturer and subsequently for the consumer of the resulting product. In this work, we have studied the dependence of the tensile strength when chipping along the adhesive layer on the type of glue, wood species, and operating conditions. We have selected the following adhesives based on polychloroprene, polyvinyl acetate and rubber. The greatest strength of the adhesive bonding when gluing solid hardwood is given by polyvinyl acetate adhesives. When using the product in conditions of changing temperature and humidity, the bonding strength decreases, in some cases significantly. In fairness, it should be noted that not only the type of glue, but also the type of wood affects the bonding strength

Production of Joints Of Eucalyptus Sp. to Obtain Edge Glued Panels

ABSTRACT This research aimed at evaluating the quality of bonded joints of Eucalyptus wood by using different faces and adhesives to produce EGP (Edge Glued Panels). Glue line shear specimens were obtained from bonded joints glued with PVAc (Polyvinyl Acetate) and EPI (Emulsion Polymer Isocyanate) adhesives, using pieces oriented with tangential, radial and intermediary faces, as well as the combination between them. The specimens were submitted to two pretreatments in order to simulate the use of joints in dry and wet environments. For shear tests, 12 treatments were obtained. The results indicated that the use of tangential x tangential and tangential x intermediary bonding faces and EPI adhesive presented better glue line shear strength for EGP in dry and wet pretreatments, respectively. The joints bonded in the radial x radial direction presented statistically inferior values when compared to the other treatments.

Enhancement of Polyvinyl Acetate (PVAc) Adhesion Performance by SiO2 and TiO2 Nanoparticles

Post press processes include various types of bonding and adhesives, depending upon the nature of adherends, the end use performance requirements and the adhesive bonding processes. Polyvinyl acetate (PVAc) adhesive is a widely used adhesive in the graphic industry for paper, board, leather and cloth. In this study, the enhancement of PVAc adhesion performance by adding different concentrations (1%, 2% and 3%) of silica (SiO2) and titanium dioxide (TiO2) nanoparticles was investigated. The morphology of investigated paper-adhesive samples was analyzed by SEM microscopy and FTIR spectroscopy. In addition, the optimal adhesion at the interface of paper and adhesive was found according to calculated adhesion parameters by contact angle measurements (work of adhesion, surface free energy of interphase, wetting coefficient). According to obtained surface free energy (SFE) results, optimum nanoparticles concentration was 1%. The wettability of the paper-adhesive surface and low SFE of interphase turned out as a key for a good adhesion performance. The end use T-peel resistance test of adhesive joints confirmed enhancement of adhesion performance. The highest strength improvement was achieved with 1% of SiO2 nanoparticles in PVAc adhesive.

Protection of lead in an environment containing acetic acid vapour by using adsorbents and their characterization

Historical museums and depositories contain collections with a number of lead objects or historical documents with lead seals. Lead is a metal which has good corrosion resistance under atmospheric conditions. On the other hand, lead corrodes in an activity in an environment which contains volatile organic compounds (mainly acetic acid and formic acid). In a depository environment, sources of volatile compounds can be the historical documents themselves, wood, plastics (those made from cellulose acetate), polyvinyl acetate adhesives, varnishes, oil or emulsion paints, etc. The aim of this work was to compare the efficiency of commercial adsorbents (activated carbon, activated alumina, zeolite, and bentonite) in the acetic acid vapours. The lead corrosion rates were determined by using lead resistometric probes. Activated alumina and activated carbon were found to be the most effective adsorbents of acetic acid vapours. On the other hand, the available zeolite had the worst sorption ability compared with the other tested substances.