Fumed silica as a filler for MUPF resin in the process of manufacturing water-resistant plywood

Abstract

This work examines the effect of applying fumed silica with nanoscopic-size particles as a filling material for melamine-urea-phenol-formaldehyde (MUPF) resin in the process of manufacturing water-resistant plywood. Moreover, this paper investigates the possibility of reducing the amount of MUPF resin mixture used in the process of gluing veneer sheets. Based on the investigations into the reactivity, viscosity and durability of MUPF resin mixture containing various amounts of nanofiller, it was found that the optimum amount of silica that can make the resin suitable for gluing sheets of veneer amounts to 2 PBW per 100 PBW of MUPF resin. The gluing properties for thus mixed resin were determined by measuring the contact angle and determining the parameters of its derivatives, which are an additional criterion for evaluating the gluing properties. The thermal stability was tested with simultaneous use of TG-DSC analysis. The experimental plywood manufactured using optimal nano-SiO 2 was tested in terms of bond quality and mechanical properties according to appropriate standards. The investigations prove that it is possible to apply fumed silica as a filling material for the resin in the process of manufacturing water-resistant plywood. Introducing the above-mentioned amount of fumed silica into the resin makes it possible to increase the activation energy of the cross-linking process of MUPF resin and to optimize the process of gluing the sheets of veneer. Moreover, it is also possible to produce plywood of the required water-resistance with the amount of adhesive mixture reduced by 30 %.

Bonding strength of benuang and duabanga glulams using their barks as phenol formaldehyde-filler

“…Figure 4 showed hydroxyl groups and moisture in technical and bark filler react with PF during curing process, and this process occurs at lower temperature [21]. Furthermore, Dukarska and Czarnecki [10] stated lower endothermic of glue mixtures was also caused by volatile substances in fillers. The DSC analysis also showed that glue mixture with additional BN bark cured in lower temperature than glue mixture with additional DB bark (Fig.…”

“…Filler can be organic or inorganic materials. Inorganic fillers that have been tried to be used for adhesive were calcium carbonate [8], glass particles [9], fumed silica [10], waste marble powder [11], and diatomite powder [12]. Organic fillers generally are biomass waste, such as walnut shell, pinenut shell, ginkgonut shell, coconut shell, periwinkle shell, palm kernel, wood flour, waste rubber, corncob residue, and wood waste ash [5,6,9,[13][14][15][16][17].…”

The effect of organofunctional nanosilica on the cross-linking process and thermal resistance of UF resin

“…Dukarska and Czarnecki prove that introducing fumed silica into MUPF resin, in the amount of 2 PBW/100 PBW of the adhesive reduces the value of activation energy of the cross-linking process [1]. Table 3 shows the effect of non-modified nano-SiO 2 on the reactivity of urea resin determined on the basis of activation energy measured with use of Kissinger and Ozawa methods.…”

“…So far, in the investigations on the use of nanosilica as an additive to urea-formaldehyde resin applied in production of plywood, particleboards and OSB, researchers used mainly non-modified silicas [1,5,22]. Roumeli et al show that silica non-modified with proadhesive agents, when introduced into UF resin, tends to create aggregates of various size and their number increases along with the silica content [5].…”

“…The most universal nanoscopic additive is synthetic silica commonly used in the pharmacy, cosmetics, construction chemicals, lacquers and others. The paper by Dukarska and Czarnecki shows that small addition of nano-SiO 2 to MUPF resin makes it possible to optimize the process of plywood production by reducing the amount of resin mixture in the process of gluing the sheets of veneer [1]. According to Leonovich et al, Lin et al, Shi et al, Roumeli et al the introduction of nanosilica into urea-formaldehyde resin contributes to the growth of physico-mechanical properties of particleboards, MDF and wood [2][3][4][5].…”