Search

Wood-plastic composites (WPC) can be regarded as environmentally-friendly materials which are mainly manufactured with recycled wood and thermoplastics. However, it is difficult to decorate WPCs with wood veneer using the types of polar adhesives which are commonly used in the woodworking industry due to the nonpolar and nonporous surfaces of WPCs. In the present study, four kinds of abrasive material, including sanding paper, industrial scouring pad, nylon and steel wire wheels were evaluated as a means of promoting adhesion between a wood fiber/high-density polyethylene (WF/HDPE) board and wood veneer using an isocyanate-crosslinking polyvinyl acetate adhesive. Based on the test results of bonding strength and water resistance, it was found that neither the sanding paper commonly used in the woodworking industry, nor steel wire commonly used in the WPC industry were particularly effective, with the scouring pad approach (nylon substrate entangled with silicon carbide) being the best choice. Scanning electron microscopy, Fourier-transform infrared spectroscopy, contact angle measurements, and roughness tests were used to analyze the surface properties of abraded surfaces. Although all four abrasion materials scraped the surface plastic layer off and exposed the wood fibers, they formed significantly different morphologies and affected surface wettability. A combination of suitable surface roughness and enough fiber exposure was found to be necessary for a WF/HDPE composite to build a good glue line. Abrasion with an industrial scouring pad might be a simple and effective method for removing a surface layer and aiding the application of a decorative layer. [ABSTRACT FROM AUTHOR]

Gelatin can act as wood adhesive for fabrication of numerous structures. Polyvinyl acetate (PVAc) is also used as wood adhesive because it provides excellent adhesion. Unfortunately, its bonds are sensitive to humid atmospheres especially at elevated temperatures. The current work explores hybridization of PVAc emulsion with finite amounts of gelatin and the resulting latex was fully characterized using different techniques, where it was found that gelatin insertion caused densification of the latex structure without affecting its stability while the viscosity increased without visual phase separation, indicating strong interactions emerged between both. Dynamic light scattering (DLS) and transmission electron microscope (TEM) confirmed a mean size of the latex particles increasing from 265 nm to 290 nm in presence of elevated doses of gelatin, with the surface charge decreasing from −42 mV to −33 mV. Turbidity measurements revealed the latex particles became more likely to coagulate in presence of increasing amounts of gelatin and formation of a more compact film that provides higher resistance to water permeation and stronger adhesion as supported by shear strength evaluations. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) proved strong interactions between PVAc with gelatin, causing higher thermal stability and possibility of use at relatively higher temperatures. X-ray diffraction (XRD) showed broadening of the peak at 2θ = 21° indicating partial destruction of the triple helical structure of gelatin, which can be correlated with the spectra of Fourier transform infrared (FTIR) that showed obvious shifts of the main peaks of PVAc due to effective insertion of gelatin. [Display omitted] [ABSTRACT FROM AUTHOR]

The determination of the efficiency of adhesives applied in glued joints, through the analysis of the percentage of wood failure, is one of the main validation parameters for the quality of gluing techniques and adhesive. However, the subjectivity of the interpretation, performance, and visual acuity of the evaluators makes the methodology subjective. This research aimed to establish a method for evaluating the behavior of the glue line in glued joints, using freely available software and digital camera images. Shear samples of glued joints with polyvinyl acetate - PVAc, resorcinol formaldehyde - RF, and melamine formaldehyde - MF were evaluated using digital images obtained by a 16.1-megapixel camera. The images were pre-processed to enable vectorization in Inkscape software, version 1.1.2. Each image was vectorized and subjected to the measurement of the areas of the generated vector layers (glue line and wood). The validation process was performed by evaluating the accuracy of vectorization. Thus, the photograph of each sample and the vectorized image were imported into ImageJ software, version 1.53. To ensure the reliability of the proposed methodology, statistical analyses of the Kappa coefficient, global accuracy, user, and producer were applied. To evaluate the efficiency of the proposed method in relation to the conventional method provided in ASTM D5266-13 , five evaluators analyzed the proportion of bond line and wood failure of the 10 samples submitted to the proposed methodology. Subsequently, a descriptive analysis of the data was carried out to evaluate the variability and subjectivity of the conventional analyses among the evaluators. It is noted that the proposed methodology achieved high efficiency in the analysis of the proportion of glue line and wood, and it can be assured by the accuracy tests performed. The research also showed that there was no agreement among the five evaluators using the conventional method. It is concluded that the proposed methodology meets the research objective, with high levels of accuracy, and confirms the subjectivity of the analyses performed with the conventional methodology. The results underscore the need for objective methodologies, employing computational techniques to reduce subjectivity in adhesive bond failure assessments, enhancing critical decisions in the selection of adhesives for industrial structural applications. • A new methodology for forest planning was proposed. • We consider the main forest genetic materials used in Brazil. • The methodology showed 81% assertiveness. • The proposed methodology had high precision and zero execution cost. • The proposed methodology is feasible and can be adapted to any other area. [ABSTRACT FROM AUTHOR]

Recent research at the University of Queensland (UQ) has led to the development of a new type of structures called "Hybrid Fiber Reinforced Polymer (FRP)-Timber structures" ("HFT"). In HFT structures, FRP is combined with timber veneers to create high-performance, lightweight, easy-to-construct structural members. These HFT members take advantage (i) of the orthotropic properties of both, timber and FRP to orientate the fiber direction to produce optimal composite properties, and (ii) of the geometry of the cross sections to maximize the load bearing capacity for a given amount of material. While preliminary experimental work has revealed as such the effectiveness of HFT structural members, no work has been carried out so far to investigate the behavior of these HFT structures. Performance of these new HFT members relies significantly on the bond between FRP and timber. This paper presents the results of an experimental study aimed at selecting a suitable commercially available adhesive for glass fiber reinforced polymer (GFRP)-to-timber bonded joints. The experimental program included 393 single lap joint tests covering four different commercially available adhesives, two different curing temperatures, and two test methods (dry and moisture cycle tests). The test results revealed that both, polyurethane (PUR) and cross-linking polyvinyl acetate emulsion (PVAx) performed as the best under dry conditions, while PUR was shown to be superior to all other adhesives when subjected to moisture cycles. Epoxy and phenol resorcinol formaldehyde adhesive (PRF) commonly used in FRP structures and laminated timber structures, resp., were found to be less performing structural adhesives for HFT structures. [ABSTRACT FROM AUTHOR]

Low strength is one of the main disadvantages of nanofibrous structures in some applications such as suture yarns. To overcome this matter, in the present research, a novel method was applied to improve the tensile properties of nanofiber yarns. For this purpose, nanofibers and particles of polyvinyl acetate (PVAc) were added as a hot melt adhesive to nanofiber yarns in order to initiate adhesive bonding between nanofibers by two approaches. In the first one, Nylon 66/ PVAc hybrid nanofiber yarn was produced in opposite charged nozzles set up. In another approach, PVAc particles were electrosprayed through one of the nozzles while nylon 66 nanofibers were producing through another one. Afterward, thermal treatment was carried out for 78 seconds on samples in different temperatures. The results indicate that tensile strength was improved up to 1.97 and 1.7 times in comparison to nylon 66 nanofiberous yarn by adding PVAc nanofibers and particles, respectively. FTIR analysis was also carried out to assess the hybrid sample composition after heat treatment. [ABSTRACT FROM AUTHOR]

Poly(vinyl acetate) (PVAc) water-resistant glues used in the wood industry and belonging to the class of durability D3 show high resistance to both water and heat compared to the usual PVAc-based thermoplastic products. In conventionally synthesised adhesives this is attained by means of cross-linking (although limited) of the linear polymer chains and moreover by using inorganic salts, such as aluminium chloride. The paper illustrates the limits of these products and presents the prospects in the chemistry of industrial-grade D3-class PVAc adhesives. More in detail, it is shown how the individual roles of both cross-linking agent and aluminium chloride contribute to the occurrence of recurring inconveniences characterising conventional PVAc-D3 glues, which include formaldehyde release during time (mostly related to the curing agent), glueline colouring and indirect staining of wood (both are mostly evident in selected wood species, in the presence of either heat or UV irradiation), acidic pH, and equipment corrosion (related to the presence of aluminium chloride). Understanding those mechanisms has constituted the basis for the development of newly synthesised PVAc-D3 glues, whose characterisation is expressly reported in the present work. Such systems have shown good adhesion to wood surfaces and have exhibited neither corrosive nor chromatic alteration evidences, as well as absence of formaldehyde emissions. All these occurrences were verified by specific tests, such as corrosion on steel, measurements of the formaldehyde content of the dispersion, and emissions from panel boards, and glueline exposure to both temperature and UV irradiation after application in selected wood species. [ABSTRACT FROM AUTHOR]

This paper presents an application of artificial neural network (ANN) to predict the bonding strength of the wood joints pressed under different conditions. An experimental investigation firstly was carried out and then an ANN model was developed based on the experimental data. In the experimental investigation, Oriental beech ( Fagus orientalis L.) and Oriental spruce ( Picea orientalis (L.) Link.) samples bonded with polyvinyl acetate (PVAc) adhesive were pressed at four different temperatures (20, 40, 60 and 80 °C) for four different durations (2, 8, 14 and 20 min). The experimental results showed that higher values of bonding strength were obtained when high temperatures were combined with short pressing duration. Similar findings could be also obtained with longer pressing time for lower temperatures. The first case may be recommended to increase the efficiency of the production process, allowing a greater quantity of production per unit time. The ANN results showed a good agreement with the experimental results. It was shown that prediction error was within acceptable limits. The results revealed that the developed ANN model is capable of giving adequate prediction for bonding strength with an acceptable accuracy level. The desired outputs of bonding strength can be thus obtained by conducting less number of time-consuming and costly experimental investigations using the proposed model. [ABSTRACT FROM AUTHOR]

Depending on the expected use of timber structures and wood-based panels jointed with adhesives, Eurocode/European standard defines various service classes for the design of buildings, where different moisture ranges might be expected. As a result, it can be assumed that the amount of moisture in the adherend has a significant impact on wood-adhesive bond lines. In-situ nanoindentation was used to investigate the influence of moisture on mechanical properties in service conditions for commonly used structural and non-structural wood adhesive systems (polyvinyl acetate adhesive PVAc, a flexible two-component melamine-urea-formaldehyde adhesive MUF, urea-formaldehyde adhesive intended for form pressing applications UF A, and particle board urea-formaldehyde adhesive UF B, and a phenol-resorcinol-formaldehyde adhesive PRF). The urea-formaldehyde adhesive intended for form pressing applications and PRF adhesives displayed better stability in elastic behaviour and very little change in creep behaviour at elevated relative humidities. The thermoplastic adhesive PVAc, particleboard urea-formaldehyde (UF A), and MUF adhesive systems with flexible thermoplastic components showed lower stability with increasing relative humidity levels above 66%. The two-component MUF adhesives showed increasing creep with increasing flexible second component at elevated relative humidities. The pre-polymerized adhesive PVAc turned out to be the most sensitive one to moisture. [ABSTRACT FROM AUTHOR]

Polyvinyl acetate (PVAc) as a thermoplastic polymer is one of the most common wood adhesive types for interior applications. For the processing of water-based PVAc wood adhesives, certain manufacturer-related parameters such as open and closed assembly time must be considered in order to avoid loss in strength properties of the adhesive joint. As for some applications, the maximum open assembly time is too short, this production-related property can be engineered by adding additives to the PVAc wood adhesive. The aim of this study was to prolong the open assembly time by post-adding different additives to the adhesive. The additives used were water, calcium carbonate, D-sorbitol, fumed silica, glycerine, methylcellulose, poly dextrose, urea, wheat flour and wheat starch. Using a simple in-situ determination method, open assembly time was measured. Additionally, the solid content and the rheological behaviour as well as the mechanical properties and the moisture absorption behaviour from dried adhesive films were determined for characterisation of the additive-PVAc adhesive mixture. A preferred additive would only prolong the open assembly time and would have little to no influence on the remaining parameters investigated. This study showed, that with the post-addition of certain additives to the PVAc adhesive, the desired production-related requirements can be adjusted. [ABSTRACT FROM AUTHOR]

Micro X-ray computed tomography (XCT) was used to analyze the 3D adhesive penetration behavior of different wood–adhesive bondlines. Three adhesives, a phenol formaldehyde (PF), a polymeric diphenylmethane diisocyanate (pMDI), and a hybrid polyvinyl acetate (PVA), all tagged with iodine for enhanced X-ray attenuation, were used to prepare single-bondline laminates in two softwoods, Douglas-fir and loblolly pine, and one hardwood, a hybrid polar. Adhesive penetration depth was measured with two separate calculations, and results were compared with 2D fluorescent micrographs. A total of 54 XCT scans were collected, representing six replicates of each treatment type; each replicate, however, consisted of approximately 1500 individual, cross-section slices stacked along the specimen length. As these adhesives were highly modified, the presented results do not indicate typical behavior for their broader adhesive classes. Still, clear penetration differences were observed between each adhesive type, and between wood species bonded with both the PF and pMDI adhesives. Furthermore, penetration results depended on the calculation method used. Two adhesive types with noticeably different resin distributions in the cured bondline, showed relatively similar penetration depths when calculated with a traditional effective penetration equation. However, when the same data was calculated with a weighted penetration calculation, which accounts for both adhesive area and depth, the results appeared to better represent the different distributions depicted in the photomicrographs and tomograms. Additionally, individual replicate comparisons showed variation due to specimen anatomy, not easily observed or interpreted from 2D images. Finally, 3D views of segmented 3D adhesive phases offered unique, in-situ views of the cured adhesive structures. In particular, voids formed by CO 2 bubbles generated during pMDI cure were clearly visible in penetrated columns of the solidified adhesive. [ABSTRACT FROM AUTHOR]

The aim of this study was to improve the bond strength resistance of polyvinyl acetate (PVAc) and urea-formaldehyde (UF) adhesives modified with nano-clay (montmorillonite) with a tropical species of wood known to exhibit adhesion related problems. These adhesives were evaluated with 1.0 and 1.5 wt% nano-clay concentrations with lap shear strength (SS), and the percentage of wood failure (PWF) in dry and wet conditions being evaluated. An additional aim of this study was to observe the presence of nano-clay within both adhesive types using Atomic Force Microscopy (AFM) and the Transmission Electron Microscopy (TEM). Color, viscosity and the thermostability of these adhesives with nano-clay were also evaluated. First, AFM and TEM studies showed adequate dispersion and impregnation of nano-clay. The viscosity of PVAc adhesive was not affected by the incorporation of nano-clay, whereas the UF adhesive was. With both PVAc and UF adhesives, the presence of nano-clay increased the L ⁎ and b ⁎ color parameters, especially when 1.5 wt% nano-clay was used. The incorporation of the nano-clay improved thermostability, as determined by thermogravimetric analysis (TGA). Finally, it was shown that the nano-clay incorporation improved SS and PWF. The highest values of SS were obtained when nano-clay was added at 1.5 wt% concentration in the PVAc adhesive under dry conditions. SS was not affected by nano-clay addition in the UF adhesive under dry conditions. However, under wet conditions, both 1.0 and 1.5 wt% loadings of nano-clay increased SS with both adhesive types. The addition of nano-clay in both proportions increased PWF by approximately 15% and between 20–30% in dry and wet conditions, respectively, for the PVAc adhesive. For the UF adhesive, PWF increased by approximately 10% under dry conditions and 25–50% in wet conditions. [ABSTRACT FROM AUTHOR]

Abstract: Nanoclay/polyvinyl acetate waterborne adhesives were prepared by using a two-step polymerization process. First, seed polymer particles containing the clay were obtained by batch miniemulsion polymerization. Then, the clay was buried within the particles by the addition of a neat monomer in the second step. The final stable dispersions could have up to 50wt% of solids content. TEM images clearly showed the presence of clay inside the polymer colloids, although not totally exfoliated. The addition of nanoclay produced adhesives with higher water and heat resistance judged by the water swelling behavior and thermal degradation properties, which was reflected also in their better adhesive performance under wet conditions (D3 tests according to EN204) and high temperatures (WATT91) of the samples containing clay with respect to the pristine dispersions. [Copyright &y& Elsevier]

Graphene gel and powder were added to polyvinyl acetate (PVA) resin to investigate its potential improving effects on shear strength of the resin. Graphene flakes were synthesized based on a simultaneous electrochemical exfoliation/deposition procedure. Flakes were decorated in face with magnetic nanocrystals in hetero-structure. They were mixed with PVA resin at 3% content, based on the wet weight of the resin. Beech wood specimens (Fagus orientalis L.) were prepared according to ASTM D143-14. Separate sets of specimens were prepared to be first heated at 165 °C and 185 °C for 4 h. Results demonstrated significant improving effect of graphene powder on shear strength of PVA resin. Graphene gel did not improve shear strength due to dilution of resin. Density functional theory simulations indicated very low adsorption energy of either pure graphene (−0.45 eV) or Ni-doped graphene (−0.91 eV) flakes on cellulose. Therefore, the improving effect was not attributed to formation of new bonds between graphene flakes and cell-wall polymers. It was concluded that graphene powder acted as a reinforcing filler in the PVA resin matrix, significantly improving its shear strength in the un-heated beech specimens. However, as a result of thermal degradation of cell-wall polymers and the consequent decrease in mechanical properties of the wood, as well as a considerable decrease in wood wettability, failures occurred within the wood structure of the heat-treated specimens rather than within the bond line. Therefore, graphene powder could not improve the overall shear strength in the heat-treated specimens at 185 °C. [ABSTRACT FROM AUTHOR]

Abstract: Cross-correlation of optical coherence tomography (OCT) images has been applied to internal imaging of PVA and two-part epoxy adhesives during cure, providing information on relative viscosity at different positions within the sample volume. Spatial resolution of a few micrometres is obtained in the original OCT images, and a few tens of micrometres in the correlation images, enabling the progress of cure to be mapped in fine detail within a small cure volume. Evidence of phase separation is seen in the OCT and correlation images of a partially-cured PVA emulsion. Mixing structure and regions of poor cure can be observed in a poorly-mixed two-part epoxy. [Copyright &y& Elsevier]

Abstract: It is hoped to develop new additives substituting for wheat flour used in UF-glue, which needs to investigate the interaction of flour with UF-glue as reference. This paper tested and contrasted the effects of wheat flour, maize powder, wheat starch and its mixture with gluten on the properties of UF-glue through measuring glue viscosity and slab pre-press strength. The viscosity-increasing in UF-glue and slab pre-press strengthening efficiency ordered from great to small as: wheat gluten, wheat flour, simulated flour, wheat starch, maize powder. SEM images, IR and XRD spectra do not show clear evidence of chemical reaction between flour and UF-glue around room temperature. The starch separated from mixture of flour with UF-glue keeps its crystallitic properties such as polarizing and gelatinizes when heated enough. For same compositions the viscosity of the mixture of suspension with UF-glue is bigger than that of the mixture of dry powder with UF-glue. Wheat flour and other powders containing wheat proteins have stronger influence on UF-glue than on poly(vinyl acetate) latex; the reason for this fact needs further in-depth study. [Copyright &y& Elsevier]

Abstract: In this study blending PVA with MUF and MF was evaluated as an approach to enhance the performance of PVA towards water and elevated temperatures. MF and MUF were added to PVA at different proportions: 15%, 30%, 50%, 70% and 100%. Blends of PVA with MF and MUF were used as adhesives to bond wood joints. The shear strength of wood joints was measured at dry and wet states, and elevated temperatures. Thermogravimetric analysis was used to study thermal stability of PVA and its blends with MF and MUF. The structural changes caused by the inclusions were characterized by Fourier transforms infrared spectroscopy (FT-IR). The results showed that shear strength of wood joints were improved by the addition of MF and MUF to PVA in all conditions. Adding small amounts of MUF or MF (as low as 15%) enhanced the performance of wood joints towards water and elevated temperatures. The extent of improvement was sometimes so high that the strength of glue line surpassed strength of wood in wet conditions leading to wood failure rather than glue failure. MF had more effectiveness in improving shear strength of wood joints than MUF in all conditions. Thermal stability of PVA was increased by MF but the effect of MUF on thermal stability of PVA was dependent on MUF proportions and temperatures. FT-IR analyses showed that there are some chemical bonds between PVA and MF. Considering costs, effectiveness and formaldehyde emission, adding 15% MF to PVA seems the optimal proportion of MF in the PVA blends. [Copyright &y& Elsevier]

The mechanical bonding properties and the failure behaviour of adhesively bonded SMC substrates were investigated under the aspect of the influence of low-profile additives on the durability of joints. For this purpose, three SMC materials with different amounts of polyvinyl acetate (PVAc) and saturated polyester were bonded with a structural and semi-structural adhesive and tested under cleavage peel test in reference condition and after thermal and hygrothermal ageing. In addition characterisations of the individual materials and their ageing effects were made. In principle, destructive testing of bonded SMC substrates showed a dependence on the used adhesive and the appearance of a type of fibre bridging. Depending on the PVAc content, different fibre tearing rates occurred. Thermal ageing led to post-crosslinking of the materials and increasing stiffness. Moreover, strong fibre tear-out appeared. Hygrothermal ageing in the SMC results in physical reversible plasticizing effects and chemical ageing by hydrolysis of the low-profile additives, presumed by performed DMTA tests. A weakened interface and disbonding failure phenomena occurred with increased PVAc content of semi-structural bonded specimens. Thus, in terms of adhesive bonding of SMC structures, a focus should be put on the type and quantity of low-profile additives used. The reduction of PVAc content led to the required quality of the joint with regard to the durability. [ABSTRACT FROM AUTHOR]

This work aimed to determine the contact angle of adhesives in eucalyptus and pine wood and the influence on bonding, besides evaluating the wood-adhesive interface of glued joints with different adhesives and weights. Wood samples of two different species (Eucalyptus spp. and Pinus spp.) and five types of adhesives (polyvinyl acetate - PVA; sodium silicate - SS; resorcinol-formaldehyde - RF; bio-content polyurethane based on castor oil - BP; and modified silicate - MS) were used. For the contact angle determination, approximately 35 μL of each adhesive was inserted on the surface of the wood and the drops were photographed at five intervals after contact with the substrate. For the glue line determination, wood sheets with dimensions of 40 cm long x 10 cm wide x 0.6 cm thick were glued using three weights. Then slides were made and the images were captured using the Axio-Vision software. For the evaluation of the wood-adhesive interface, a scanning electron microscope was used. The mean values of contact angles ranged from 28.2 to 87.9° for eucalyptus wood and from 26.0 to 86.9° for pine wood. The smallest contact angles were obtained with the BP adhesive and the largest with the PVA adhesive. For eucalyptus wood, the lowest thickness of the glue line was 25.9 μm (SS adhesive) and the largest was equal to 149 μm (MS adhesive). For pine wood, the smallest thickness was 3.0 μm (BP) and the largest was 128 μm (PVA). Regardless of the wood used, the contact angle of the adhesives decreased with increasing time. The viscosities of the adhesives influenced the contact angle and the wettability of the wood. BP, PVA, and RF adhesives penetrated the wood, filling cell cavities adjacent to the main glue line. [ABSTRACT FROM AUTHOR]

One of the most commonly used adhesive types in nonstructural applications of wood, with many advantageous characteristics, is polyvinyl acetate (PVAc), which is produced in four different classes (D1-D4), according to its durability to humidity and climatic conditions. In this study, six of the most commonly used and worldwide commercially available brands of PVAc wood adhesives of D3 durability class, of different cost and origin (locally produced or imported), were obtained from the market, aiming to study and compare the "wood to wood" adhesion ability of beech wood, which is one of the most important species used in furniture production in Europe, and assess the quality of the produced gluelines, according to standards [EN 204, EN 205]. Three different conditioning treatment processes were applied to these 6 D3-PVAc adhesives lap joint specimens the "tensile shear strength" of the specimens was determined, while after their destruction, the "wood failure" percentage was visually assessed on the bonding surfaces. According to the results, the tensile shear strength values of the joints ranged between 11.48 and 13.18 N/mm2, revealing satisfying adhesion strength for all the different cases of adhesive brand and process applied after adhesion, meeting the requirements of the standard for D3 durability class categorization. The factor of "adhesive brand type" affected significantly the shear strength values, whereas neither the "conditioning treatment" applied to the specimens, nor the interaction between the two factors of "adhesive brand type" and "treatment", revealed a significant effect on the shear strength values of the specimens, indicating a good bonding performance, either under ambient conditions or under conditions of high humidity environments. The differences in the adhesives prices (euro/100 g), origin and other technical characteristics (viscosity, solids content), did not affect the shear strength of the joints. The satisfying bonding quality of the studied adhesives was verified by the high "wood failure" percentages recorded on almost all the specimens, as well as the stereoscopically observed bonding lines, suggesting the high potential of resistance to humidity and aging effect, which could extend even more the applications range of such environmentally friendly adhesives. [ABSTRACT FROM AUTHOR]

Wood-fiber-reinforced thermoplastic plastic composite is a type of environmentally friendly material. However, its application in furniture and interior decoration is limited due to its lack of wood texture. In this work, wood-veneer-facing decoration was explored to beautify the composite's appearance. Surface planning and slight sanding were applied to wood-fiber–high-density-polyethylene (WF-HDPE) composite. Polyvinyl acetate emulsion was used as adhesive, and the veneer-faced WF-HDPE composite floor was prepared by the hot-pressing method. The bonding line was analyzed with Fourier-transform infrared spectroscopy and scanning electron microscopy. Planning plus sanding treatment removed the HDPE film on the composite surface and exposed the wood fibers to react with the adhesive. The rough surface provided all decorative samples bonding strengths higher than 0.9 MPa. The bond line could stand 63 °C water soaking for 3 h without delamination. The hot-pressing temperature exhibited a significant effect on surface bonding strength. The optimized hot-pressing technique included a hot-pressing temperature of 80 °C, a hot-pressing time of 10–20 min, and a hot-pressing pressure of 0.2 MPa. With this combination, the surface-decorative veneer retained the beauty of its original color. [ABSTRACT FROM AUTHOR]