硅藻土对单宁酸/淀粉/聚乙烯醇木材用复合胶黏剂的性能影响

Effect of Diatomite on Properties of Tannic Acid/Starch/Polyvinyl Alcohol Composite Adhesives for Wood

制备了硅藻土(Diatomite)增强单宁酸(Tannic acid)/淀粉(Starch)/聚乙烯醇(PVA)胶黏剂(DTSP),探究了硅藻土添加量对DTSP胶黏剂性能的影响。采用傅里叶变换红外光谱(FT-IR)对DTSP胶黏剂的化学结构进行了表征。结果表明,硅藻土通过硅羟基与淀粉基胶黏剂中的羟基形成氢键从而发生交联。采用扫描电子显微镜(SEM)对固化后胶层的断面进行分析,可以观察到添加了硅藻土的DTSP胶黏剂与未添加硅藻土的TSP胶黏剂相比较为粗糙,这表明DTSP胶黏剂形成了稳定而坚韧的交联网络。通过对胶黏剂的固化性能和黏结性能测试,当硅藻土的添加量为3%时,DTSP胶黏剂的综合性能最优,其木材-木材拉伸剪切强度为3.16 MPa,经过24 h去离子水浸泡后的拉伸剪切强度为1.37 MPa。与TSP胶黏剂相比,固化时间缩短了20 min,固含量由26.15%提升至36.25%。吸湿率和饱和吸湿率都有下降,接触角也由70.2°提升至85.7°。

Diatomite enhanced tannic acid/starch/polyvinyl alcohol(PVA)adhesives(DTSP)were prepared,and the effect of diatomite addition on the performance of DTSP adhesives was investigated.The chemical structure of the DTSP adhesive was characterized by Fourier transform infrared spectroscopy(FT-IR).The results showed that diatomite crosslinks by forming hydrogen bonds with hydroxyl groups in starch-based adhesives through silica hydroxyl groups.The cross-section of the cured adhesive layer was analyzed by scanning electron microscopy(SEM),and it was observed that the DTSP adhesive had a rougher surface than the TSP adhesive without added diatomite,indicating the DTSP adhesive layer formed the stable and toughness cross-linking network.By testing the curing and bonding properties of the adhesives,when the diatomite was added at a level of 3%,the DTSP adhesive had the best overall performance,with a wood-wood tensile shear strength of 3.16 MPa,and a tensile shear strength of 1.37 MPa after soaking in water for 24 hours,the curing time was shortened by 20 minutes and the solid content was increased from 26.15%to 36.25%,compared with the TSP adhesive.The moisture absorption rate and saturated moisture absorption rate were decreased,and the contact angle was also improved from 70.2°to 85.7°.