WOOD RESEARCH Volume 62, Number 5, 2017
Kaimeng Xu, Kunyong Kang, Can Liu, Yuanbo Huang, Gang Zhu, Zhifeng Zheng, and Wenlun Li

The effects of expoxidized soybean oil on the mechanical, water absorption thermal stability and melting processing properties of wood plastic composites

To promote the environmentally friendly properties of wood plastic composites (WPC) fabricated via a polyvinyl chloride resin matrix, the effects of different amounts (0, 5, 15, 25, and 35 phr) of expoxidized soybean oil (ESO) on mechanical strengths, thermal stability, melting processing properties, and water absorption of the composite samples were studied. The results show that the tensile strength of WPC decreased. However, the elongation at break, water absorption and thickness swelling rates increased, especially for ESO addition amounts beyond 15 phr. The flexural strength and modulus of WPC followed an upward trend initially (at 5 phr ESO), then switching to a downward trend. The initial thermal stability at the first thermal decomposition stage and the melting processing temperature of the composites ewere effectively improved with the increase of ESO level. Compared to the samples without added ESO, the maximum thermal decomposition temperature (Tmax1 and Tmax2) values of the composites increased by 31°C and 8°C, respectively, while the melting processing temperature of the composites significantly decreased by 24°C corresponding to an added level of 35 phr. In summary, the WPC samples with 5-15 phr ESO addition not only effectively retained their the mechanical strengths and water absorption stability, but also improved their the thermal stability and melting processing properties.

WOOD RESEARCH Volume 65, Number 5, 2020
Zhongxi Zhou, Chungui Du, Huilong Yu, Xiaoling Yao, and Qiuli Huang

Promotion effect of nano-SiO2 on hygroscopicity, leaching resistance and thermal stability of bamboo strips treated by nitrogen-phosphorus-boron fire retardants

Whereas hygroscopicity an leaching resistance often have a bad influence on performance of fire-retardants, in this work, nano-SiO2 sol was added to different nitrogen-phosphorus-boron fire retardants to make four new compounds to impregnate bamboo strips, named: (1) ammonium dihydrogen phosphate + disodium octaborate tetrahydrate (AD), (2) ammonium dihydrogen phosphate + disodium octaborate tetrahydrate + nano-SiO2 sol (ADS), (3) ammonium dihydrogen phosphate + boric acid (AB), and (4) ammonium dihydrogen phosphate + boric acid + nano-SiO2 sol (ABS). After that, the hygroscopicity, leaching resistance and thermal stability were studied by scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDX), thermogravimetric (TG) and fourier-transform infrared spectrometer (FTIR), and the optimal compound fire retardant is ABS. The results show that the addition of nano-SiO2 sol can not only reduce the hygroscopicity of fire-retardant bamboo strips effectively, but also improve its leaching resistance. The results also indicate that compared with non-fire-retardant bamboo strips, the thermal stability of bamboo strips treated with AB and ABS was improved significantly, and there was no significant difference between AB and ABS.

WOOD RESEARCH Volume 66, Number 1, 2021
Günay Özbay, Erkan Sami Kokten, and Ayhan Ozcifci

Synthesis and characterization of resol type phenol-formaldehyde resin improved by SiO2-Np

In this work, resol type phenol–formaldehyde (RPF) resin was modified with silicon dioxide nanoparticles (SiO2-Np). SiO2-Np was added at varying ratios from 1 to 4 wt.% to improve the bonding performance of the RPF resins. The physical characteristics of the nano-modified RPF (nano-RPF) resins were examined. The effects of modification were studied by Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The results of FT-IR revealed that the nano-RPF resins were successfully produced by phenol, formaldehyde, and SiO2-Np. The nano-RPF resins demonstrated high thermal stability at temperatures above 500°C. The adhesive performance of the nano-RPF resins was investigated under dry and wet conditions. The nano-RPF resins indicated better adhesive performance than unmodified RPF resin. The RPF resin could be improved by SiO2-Np.