Mariusz Mamiński

Improved Water Resistance and Adhesive Performance of a Commercial UF Resin Blended with Glutaraldehyde

The influence of glutaraldehyde blend on the properties of a commercially available resin in moist conditions was investigated. A UF resin with very low water resistance was blended with glutaraldehyde prior to the thermosetting step and the adhesive performance of the modified adhesive systems was studied. Experiments were performed on birch two-layer co-oriented plywood. It was shown that blending a commercial glue-mix as sold with glutaraldehyde can be an effective way to improve water resistance of the glue without introducing additional –NH2 moiety. It was also found that glutaraldehyde does not deteriorate properties of the glue in the dry state, while glue susceptibility to boiling water is markedly reduced.

Hyperbranched Polyether as a Modifying Agent for Urea-Formaldehyde Resins—Hardness and Strength Control Tool

A commercially available urea-formaldehyde (UF) resin was blended with a hyperbranched polyether (HBP) obtained from glycerol being a by-product in biodiesel production. The mechanical properties of the cured polymeric blends are described in this article. It was found that low addition (3 wt%) of the modifier significantly improves the hardness (16%) and the compressive shear strength (17%) of the polymer, whereas water absorption remains unaffected. It was also shown that blending UF resins with hyperbranched polyethers can be an effective tool for controlling mechanical properties and dimensional stability of the polymeric systems.

Gluability of thermally modified beech (Fagus silvatica L.) and birch (Betula pubescens Ehrh.) wood

Abstract One of the main disadvantages of wood is hygroscopicity resulting from its polar character. The sorption–desorption of water causes unwanted swelling and shrinkage in wood. Thermal modification substantially reduces this inconvenient feature. Unfortunately, the same chemical changes that reduce water sorption alter the polar character of the material and result in poorer wetting of thermally treated wood by waterborne adhesives. Gluability of thermally modified beech (Fagus silvatica L.) and birch (Betula pubescens Ehrh.) wood with two commercial amino resins, melamine–urea–formaldehyde (MUF) and melamine–formaldehyde (MF), and a two-component polyurethane (PUR) adhesive was investigated. Both wood species were modified according to two temperature regimes: 160°C and 190°C. Shear strengths of the joints were then determined according to EN 205:2003 standard. The results showed that thermally modified beech and birch wood can be effectively glued not only with commercially available PUR adhesives, but also with aqueous MF and MUF resins. The resultant shear strengths of the joints were limited by the strength of the thermally modified substrate.

Wood-mineral wool hybrid particleboards

The objective of this work was to compound mineral wool with wood particles in the production of particleboards of reduced flammability. Three series of boards with various contents of mineral wool (10, 20, 30 wt%) were successfully manufactured using urea-formaldehyde resin as binder. Thickness swelling, mechanical and thermal properties as well as ignitability of the boards were assessed. It occurred that reduced ignitability is accompanied by a decrease in mechanical performance.

Simple urea-glutaraldehyde mix used as a formaldehyde-free adhesive: effect of blending with nano-Al2O3

A formaldehyde-free adhesive based on urea (U) and glutaraldehyde (GA) was developed. High reactivity of the urea-glutaraldehyde mix at ambient temperature allows for its cold setting. The glues of GA/U molar ratio between 0.8 and 1.2 were examined. It was found that for the satisfactory performance of the system, blending with nano-Al2O3 was necessary.

Application of polystyrene as binder for veneers bonding—the effect of pressing parameters

The possibility of veneer bonding with recycled polystyrene was examined. Five pressing regimes were studied. It was shown that low-pressure pre-heating is a necessary step allowing for increasing final shear strength of the wood-thermoplastic joints and avoiding indentation of thermoplastic particles to wood.

Physical and mechanical properties of thin high density fiberboard bonded with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU)

ABSTRACT 1,3-dimethyl-4,5-dihydroxyethyleneurea (DDHEU) and 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) were used as the binders in 3-mm high density fiberboard (HDF) manufacturing. The studies focus on the physical and mechanical properties of boards bonded with DDHEU or DMDHEU as a potential substitute for typically used urea-formaldehyde (UF) resins. The adhesive loads were 8% or 12%. The UF-bonded boards of same resin load were used as the controls. Applied pressing time ranged between 4 and 5 minutes. The results indicate that the use of DDHEU or DMDHEU as binders enhanced physical and mechanical properties of the boards. It was found that properly set pressing scheme and resin type allowed produce DDHEU- and DMDHEU-bonded HDF that exhibited comparable or superior performance when compared to the UF-bonded reference series and complied with European Standards. The best performing boards exhibited internal bond 1.3 MPa, modulus of elasticity 9656 MPa, modulus of rupture 56.5 MPa, thickness swelling 14% and formaldehyde release below 3.0 mg/m2h. Due to low reactivity of DDHEU and DMDHEU at temperatures below 160°C, the approach is effective for thin boards only.

Properties of particleboard produced from post-industrial UF- and PF-bonded plywood

An approach based on the recycling of waste plywood as a recovered wood resource for the particleboard industry is described. It is demonstrated that post-industrial urea- (UF) and phenol-formaldehyde (PF) bonded plywood can be effectively shredded to the form of the recovered particles that can be a valuable material in particleboard manufacturing. The effects of shredding conditions and binder type on the recovered particles characteristics and the mechanical properties of the particleboards were analyzed. It is shown that the substitution of 20–100% of virgin particles with the recovered material is possible without affecting the performance of the particleboard.

A Critical Role for the Presence of Lignocellulosic Material in the Determination of Wood Buffering Capacity

The currently used determinations of wood buffering capacity, which are based on pH-metric titrations of aqueous wood extracts, neglect the effect of lignocellulosic material and the role of its insoluble constituents. This study examined the influence of the presence of wood in a system subjected to titration. A comparison of the results obtained from pine chip extracts and chip suspensions showed that the presence of wood and the wood-to-water ratio were critical factors that affected the measurement of the wood buffering capacity. The evidence showed that the resulting determination may vary by up to six times (0.28–1.99 ml/g), depending upon the conditions of the titration. In addition, it was found that the presence of wood had a neutralizing effect over the course of prolonged pH observations.

Empty Fruit Bunches in the Race for Energy, Biochemical, and Material Industry

At present, empty fruit bunch (EFB) is used particularly as a substitute for wood fiber in few industries. Nevertheless, the end products have been reported to be relatively inferior to those made from wood and performed below the par. This chapter provides a platform to delve into the unseen keys and real facts of EFB in renewable energy, derivatives, and material industries. EFB characteristics (cross-sectional observations, chemical compositions, and inorganic element analysis) and qualities (tensile stress test and fiber morphometric measurement) are presented, and a comparison is made with softwood and hardwood. The anatomical features of EFB fiber consist of 75 % fibers and 25 % vascular bundles in terms of volume/volume. In terms of mechanical properties, EFB fibers have relatively lower specific tensile stress value compared to most woods. The presence of round, spiky-shaped silica compounds in EFB may hinder the quality of the panelboard, solid biofuel, and biochemical derivatives industries. Major amounts of alkaline cations in EFB present a problem to the combustion issue for renewal energy. Relating the characteristics and quality of EFB to the respective industries proved that EFB is an encumbrance to them. Conclusively, developing a proper treatment system to manipulate the characteristics and quality of EFB is crucial so that EFB can be pushed toward commercialization.