Materials Technology Research Group (MaTReC), School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
Materials Technology Research Group (MaTReC), School of Chemical Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
Int J Biol Macromol. 2019 Feb 1;122:713-722. doi: 10.1016/j.ijbiomac.2018.11.009. Epub 2018 Nov 3.
The recent study focused on lignin-phenol-glyoxal (LPG) as an alternative way to replace toxic formaldehyde used in commercially available wood adhesives. The concern of the uses of carcinogenic formaldehyde in wood adhesive industry has become major problem over human health, environmental and economy issues. In this study, lignin isolated from Kenaf (Hibiscus cannabinus) via soda and Kraft pulping were modified into SLPG (soda lignin-phenol-glyoxal) and KLPG (Kraft lignin-phenol-glyoxal) adhesives and were compared to phenol-formaldehyde (PF). Complementary analyses such as Fourier Transform Infrared (FTIR) spectroscopy, H and C Nuclear Magnetic Resonance (NMR) spectroscopy, thermal stability; Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were utilized to characterize all isolated lignin samples. The physical properties of the resins were further characterized in term of viscosity, gel time and total solid content. It was found that soda lignin comprised higher phenolic OH content and greater molecular weight compared to Kraft lignin. Various molar ratio of adhesives were applied on plywood and were mechanically tested. The 30% (w/w) SLPG has shown to have higher tensile strength and internal bonding stress at 72.08 MPa and 53.83 N mm respectively to that of PF.
本研究专注于利用木质素-酚-乙二醛（LPG）替代市售木材胶粘剂中使用的有毒甲醛。木材胶粘剂行业使用致癌甲醛引起了人们对人类健康、环境和经济问题的关注。在这项研究中，通过苏打法和 kraft 法制取的麻疯树（Hibiscus cannabinus）木质素被改性为 SLPG（苏打木质素-酚-乙二醛）和 KLPG（ kraft 木质素-酚-乙二醛）胶粘剂，并与苯酚-甲醛（PF）进行了比较。利用傅里叶变换红外（FTIR）光谱、H 和 C 核磁共振（NMR）光谱、热稳定性、热重分析（TGA）和差示扫描量热法（DSC）等补充分析方法对所有分离的木质素样品进行了表征。树脂的物理性能进一步通过粘度、凝胶时间和总固体含量进行了表征。结果表明，与 kraft 木质素相比，苏打木质素具有更高的酚羟基含量和更大的分子量。将不同摩尔比的胶粘剂应用于胶合板，并进行力学测试。30%（w/w）的 SLPG 表现出更高的拉伸强度和内结合强度，分别为 72.08 MPa 和 53.83 N/mm，高于 PF。
