Li Fan, Ye Cuiyin, Huang Yanhui, Liu Xianmiao, Fei Benhua
College of Materials Science and Technology, Beijing Forestry University, Beijing 100083, China.
International Center for Bamboo and Rattan, Beijing 100102, China.
Polymers (Basel). 2021 Mar 12;13(6):876. doi: 10.3390/polym13060876.
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.
采用不同含量（0 wt%、1 wt%、3 wt%）的纳米铜对酚醛（PF）树脂进行改性，以提高杉木的力学性能。通过透射电子显微镜（TEM）、原子力显微镜（AFM）、环境扫描电子显微镜（ESEM）、傅里叶变换红外光谱（FTIR）、纳米压痕（NI）和传统力学测试来测定样品的形态、化学、微观力学和微观力学性能。TEM和AFM结果表明，原位合成的纳米铜颗粒在PF树脂中分散良好，呈球形，直径约为70 nm。从FTIR检测到的化学变化推断，纳米铜改性PF树脂渗透到杉木细胞壁中，并通过形成交联结构与半纤维素的乙酰基相互作用。因此，用纳米铜改性PF树脂处理后，杉木细胞壁的微观力学性能得到增强。PF-1-Cu树脂（1 wt%纳米铜）在木材中的填充使细胞壁的弹性模量（MOE）和硬度分别提高了13.7%和22.2%。此外，浸渍PF-1-Cu树脂的杉木的冲击韧性和抗压强度比PF-0-Cu树脂分别高21.8%和8.2%。因此，原位合成的纳米铜改性PF树脂由于改善了扩散性能并增强了力学性能，是一种对杉木有效的处理方法。
