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A normal temperature cured starch-based wood adhesive was prepared using dry method esterification and polyisocyanate prepolymer crosslinking. The effects of esterification and crosslinking on the properties of corn starch adhesive were investigated. The esterified starch and adhesive were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), dielectric analysis (DEA), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results showed that maleic anhydride (MAH) esterified starch was obtained using dry method esterification. After esterification, the crystal type of starch did not change, but the crystallinity of starch decreased. The distribution of adhesive at the bonding interface was improved after esterification. The prepolymer improved the thermal stability of the adhesive, and the optimal addition of prepolymer was 10%.

The aim of this work was to study silane-modified wood flour/poly(lactic acid) (PLA) blends and the effect of blending on the properties of the wood flour/PLA composites. The surface of the wood flour used as filler was successfully modified by silane, as demonstrated by Fourier transform infrared spectroscopy (FTIR) results. The influence of silane types and content on the morphology, mechanical properties, and water absorption were studied. Scanning electron microscopy (SEM) results demonstrated that the KH-550 silane was the most effective modifier for improving the compatibility, mechanical properties, and water absorption of the blend. The appropriate additive content was 1.5% (relative to wood flour content). As the KH-550 content increased, the mechanical strength and elongation at the break first increased and then slightly decreased. These properties reached a maximum at 1.5% KH-550. The water resistance of the blend also was improved at a KH-550 content of 1.5%.

Utilizing wood powder and corn starch as the main materials with polyurethane adhesive as a cross-linking agent, the starch/wood powder composite material was prepared via molding forming techniques. The effects of wood powder mesh and addition of wood powder on the properties of composite material were investigated. The compatibility of starch and wood powder and the thermal stability of composite were evaluated by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMA), respectively. The mechanical properties and water absorption of composite material were also tested. The results showed that the mechanical properties and water resistance of composite material first increased and then fell with increasing mesh, and the best performance was obtained when the mesh ranged from 80 to 100. The best compatibility, mechanical properties, water resistance, and thermal stability of composite material was obtained with 10% polyurethane crosslinking agent addition.

Starch adhesive was prepared utilizing corn starch, polyvinyl alcohol, and borax as raw materials. A certain amount of water-soluble carboxymethyl cellulose (CMC) was added in the preparation process, and a certain percentage of polymethylene polyphenylene isocyanate pre-polymer as cross-linking agent was used to improve its water resistance. To evaluate the water resistance, three-layer plywood was fabricated by hot pressing, and bonding strength was measured using a mechanical testing machine according to the National Standard of the People’s Republic of China GB/T 17657-2013. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to characterize curing of the adhesion. The results showed that the initial viscosity, solids content, and bonding strength of the starch adhesive, as well as the interface compatibility between starch adhesive and pre-polymer, were all improved. The curing temperature of the adhesive decreased, and the optimal addition of CMC was 0.375%.

The safety of wood-plastic planks based on predicted modulus of rupture (MOR) is presented in this paper. Three different nondestructive testing (NDT) methods were used as checking tools for dynamic modulus of elasticity (MOE) of wood-plastic planks. The MOR was determined by a three-point bending test. The regression relationship between various dynamic MOE and MOR was evaluated to predict MOR of other identical wood-plastic planks. Furthermore, improved first-order second-moment (FOSM) method was used to analyze reliabilities based on measured and predicted MOR, and evaluate safety of them in service. Results indicated that reliabilities of other identical wood-plastic planks based on predicted and measured MOR were almost the same. The greatest difference between them was 0.01%; therefore, their reliability could be analyzed by predicted MOR.

Environmentally friendly particleboard was prepared with wheat straw, an inexpensive material. The particleboard was produced by a mixing process, using a composite adhesive comprised of urea-formaldehyde (UF) adhesives and EPU. The performance of the board was evaluated by measuring internal bonding strength (IB), thickness swelling, modulus of rupture (MOR), modulus of elasticity (MOE), and formaldehyde emission. The experimental results showed that maximum of dry and wet internal bonding strength, modulus of rupture, modulus of elasticity were 0.45MPa, 0.18MPa, 31.80MPa, and 5043MPa, respectively. The thickness swelling (TS2h) and thickness swelling (TS24h) were 3.9% and 10.7%, respectively. The composite adhesives and particleboards were measured by differential scanning calorimentry (DSC), dynamic mechanical analyzer (DMA), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) measurements. The results indicated that the composite adhesive of UF/EPU could contribute to excellent mechanical, thermal, and water-resistant properties of the wheat straw particleboards.