ABSTRACT

The reinforcement of pristine nanoclay (PNC) and modified nanoclay (MNC) in urea-formaldehyde (UF) resins at the alkaline stage of synthesis was investigated in this work. The modification of PNC using copper (II) chloride (CuCl₂) as transition metal ions was carried by three different modification methods that were coded as Cu-MNC (25, 36), Cu-MNC (60, 6), and Cu-MNC (80, 3), respectively. The modification of PNC was characterized by X-ray diffraction, showing the increased d-spacing after the modification. The reinforcement of 5 wt% of PNC and Cu-MNC at the alkaline reaction of UF resins that were coded as UF/PNC, UF/MNC (25, 36), UF/MNC (60, 6), and UF/MNC (80, 3). The X-ray diffraction study showed that the addition of PNC and Cu-MNC into the UF resins decreased the crystallinity of resins from 48.1% to 45% for UF/PNC and 25% for all UF/MNC. The curing behavior exhibited that the activation energy of UF resins decreased with addition of PNC and Cu-MNC. The loading of PNC and Cu-MNC into UF resins improved the adhesion and reduced the formaldehyde emission of UF resins in plywood. Statistical analysis suggested that UF/MNC (80, 3) produced plywood with greater adhesion strength and lower formaldehyde emission over other modified resins.

摘要

这项工作研究了在合成的碱性阶段，原始纳米粘土 (PNC) 和改性纳米粘土 (MNC) 在脲醛 (UF) 树脂中的增强作用。使用氯化铜 (II) (CuCl ₂ ) 作为过渡金属离子对 PNC 的修饰通过三种不同的修饰方法进行，编码为 Cu-MNC (25, 36)、Cu-MNC (60, 6) 和 Cu-跨国公司 (80, 3)，分别。PNC 的修改通过 X 射线衍射表征，显示增加的d-修改后的间距。在编码为 UF/PNC、UF/MNC (25, 36)、UF/MNC (60, 6) 和 UF/MNC 的 UF 树脂的碱性反应中，5 wt% 的 PNC 和 Cu-MNC 得到增强（ 80, 3). X 射线衍射研究表明，在 UF 树脂中添加 PNC 和 Cu-MNC 后，UF/PNC 树脂的结晶度从 48.1% 降低到 45%，所有 UF/MNC 树脂的结晶度降低 25%。固化行为表明，随着 PNC 和 Cu-MNC 的加入，UF 树脂的活化能降低。将 PNC 和 Cu-MNC 负载到 UF 树脂中可提高胶合板中 UF 树脂的粘合力并降低甲醛释放量。统计分析表明，与其他改性树脂相比，UF/MNC (80, 3) 生产的胶合板具有更高的粘合强度和更低的甲醛释放量。