The aim of the study was to investigate the effect of two different types of lignosulfonate (LS1 and LS2) added to urea–formaldehyde adhesive on the performance properties of five-layered plywood panels. The physical properties (density, thickness swelling, water absorption and moisture content), mechanical properties (modulus of rupture, modulus of elasticity and bonding quality) and free formaldehyde emission were evaluated in accordance with international standards. The results show that the lignosulfonate used in the production of plywood panels improves not only mechanical properties but also physical properties. Furthermore, the reinforcement caused by the use of proper lignosulfonate resulted in a decrease in free formaldehyde content. Using 3% LS1, eco-friendly plywood panels with improved physical (max. 22.40%) and mechanical properties (max. 42.40%) and drastically reduced free formaldehyde emissions (max. 16.27%) can be produced. It was concluded that lignosulfonates, as a byproduct of the pulping industry, can be used as a high-value additive in formaldehyde-based adhesives for engineered wood composites.

中文翻译：

---

木质素磺酸盐增强工程木质复合材料的性能

该研究的目的是研究脲醛胶粘剂中添加两种不同类型的木质素磺酸盐（LS1 和 LS2）对五层胶合板性能的影响。根据国际标准评价物理性能（密度、厚度膨胀、吸水率和含水率）、机械性能（断裂模量、弹性模量和粘合质量）和游离甲醛释放量。结果表明，用于生产胶合板的木质素磺酸盐不仅可以提高机械性能，还可以提高物理性能。此外，使用适当的木质素磺酸盐引起的增强导致游离甲醛含量降低。采用 3% LS1 环保胶合板，物理性能得到改善（最大 22. 40%）和机械性能（最大 42.40%）以及游离甲醛排放量（最大 16.27%）大幅降低。结论是，木质素磺酸盐作为制浆工业的副产品，可用作工程木质复合材料的甲醛基粘合剂的高价值添加剂。