Incorporation of In Situ Synthesized Nano-Copper Modified Phenol-Formaldehyde Resin to Improve the Mechanical Properties of Chinese Fir: A Preliminary Study

Abstract

Phenol-formaldehyde (PF) resin, modified using nano-copper with varying contents (0 wt%, 1 wt%, 3 wt%), was manufactured to improve the mechanical properties of Chinese fir. The morphology, chemical, micromechanical and micromechanical properties of the samples were determined by transmission electron microscopy (TEM), atomic force microscopy (AFM), environmental scanning electron microscopy (ESEM), Fourier transform infrared spectroscopy (FTIR), nanoindentation (NI) and traditional mechanical testing. The TEM and AFM results indicated that the in situ synthesized nano-copper particles were well-dispersed, and spherical, with a diameter of about 70 nm in PF resin. From the FTIR chemical changes detected by FTIR inferred that the nano-copper modified PF resin penetrated into the Chinese fir cell walls and interacted with the acetyl groups of hemicellulose by forming a crosslinked structure. Accordingly, the micro-mechanical properties of the Chinese fir cell walls were enhanced after treatment with nano-copper modified PF resin. The filling of the PF-1-Cu resin (1 wt% nano-copper) in the wood resulted in 13.7% and 22.2% increases in the elastic modulus (MOE) and hardness, respectively, of the cell walls. Besides, the impact toughness and compressive strength of the Chinese fir impregnated with PF-1-Cu resin were 21.8% and 8.2% higher than that of the PF-0-Cu resin. Therefore, in situ synthesized nano-copper-modified PF resin is a powerful treatment method for Chinese fir due to improved diffusive properties and reinforcement of the mechanical properties.

Analyses of Impregnation Quality and Mechanical Properties of Radiata Pine Wood Treated with Copper Nanoparticle- and Micronized-Copper-Based Wood Preservatives

“…This has been reported for the hardness of the fiber cell walls impregnated with copper nanoparticles and modified resin. Researchers found that the copper nanoparticles diffused easily into the intercellular spaces and the cell wall and the formation of a complex cross-linking in the cell wall [41]. This contrasts with water-borne solutions that use metal oxides, which undergo a hydrolytic reaction when reacting with hemicelluloses; therefore, they end up oxidizing the cell wall components and consequently reduce the properties of wood [42].…”

Enhanced bamboo interfacial bonding performance on the basis of toughening phenol formaldehyde resin by flour

“…[10] Phenol formaldehyde (PF) resin, due to its excellent bonding strength, heat resistance, water resistance, and abrasion resistance, [11,12] currently is considered as one of the most commonly used adhesives in wood and bamboo bonding. [13][14][15] . However, due to the highly crosslinked degree of the PF resin network molecular structure after curing, brittle fracture is easy to occur.…”