Chang Liang, Wang Yuanwu, Chen Xueqi, Ren Yiping, Luo Xiaoxi
Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, China.
Polymers (Basel). 2023 Jul 5;15(13):2957. doi: 10.3390/polym15132957.
In order to elucidate the importance of grafting in the compatibilization process of silane coupling agents, poplar veneer was treated with silane coupling agents and grafted under different heating conditions. The treated veneers were used composited with PE film to prepare different plywood samples. XPS and WCA were used to analyze the effect of grafting conditions on the surface properties of the silane-treated veneer. The results showed that free silanols can physically be adsorbed onto all silane-treated veneer surfaces, forming hydrogen-Si-O-Si- bonds and therefore increasing the water contact angle. Only under heating conditions could the -Si-O-Si- be converted into covalent -Si-O-C- bonds, which helped to improve the bonding strength. When silane-treated veneer was grafted at 120 °C for 90 min, the tensile shear strength of plywood reached 1.03 MPa, meeting the requirements of GB/T 9846.3-2004 for outdoor materials. Enhanced interlock between silane-modified veneer and PE film was observed under the optimal grafting condition by SEM. The better interface structure allowed improvement of thermal stability. DMA results showed that the retention rate in storage modulus at 130 °C was 60% for the grafted sample, while the retention rate for the ungrafted sample was only 31%.
为了阐明接枝在硅烷偶联剂增容过程中的重要性，对杨木单板进行硅烷偶联剂处理，并在不同加热条件下进行接枝。将处理后的单板与PE膜复合制备不同的胶合板样品。采用XPS和WCA分析接枝条件对硅烷处理单板表面性能的影响。结果表明，游离硅醇可物理吸附在所有硅烷处理的单板表面，形成氢 -Si-O-Si- 键，从而增大水接触角。只有在加热条件下，-Si-O-Si- 才能转化为共价 -Si-O-C- 键，这有助于提高粘结强度。当硅烷处理的单板在120℃下接枝90分钟时，胶合板的拉伸剪切强度达到1.03MPa，符合GB/T 9846.3-2004对室外材料的要求。通过SEM观察到在最佳接枝条件下，硅烷改性单板与PE膜之间的互锁增强。更好的界面结构有助于提高热稳定性。DMA结果表明，接枝样品在130℃下储能模量的保留率为60%，而未接枝样品的保留率仅为31%。
