Liu Pin, Liu Xiongmin, Saburi Tei, Kubota Shiro, Huang Pinxian, Wada Yuji
Department of Science and Technology, Guangxi University for Nationalities, Nanning 530006, China.
College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China.
ACS Omega. 2020 Nov 3;5(45):29102-29109. doi: 10.1021/acsomega.0c03736. eCollection 2020 Nov 17.
Rosin is a sustainable resource, which is mainly composed of resin acid. Rosin-modified resin is widely used in adhesives, inks, coatings, and other fields, and its stability is very important for the production, storage, and use of products. Thermal stability and reactivity of three resin acids (levopimaric acid, neoabietic acid, and dehydroabietic acid) and four rosin-modified resins were studied using an accelerating rate calorimeter (ARC). They are stable, and exothermic reactions do not occur even when they were heated to 200 °C under a nitrogen atmosphere, but they are unstable under an oxygen atmosphere. The mechanism of the oxidation reaction process was found: first, resin acids absorb oxygen, and then an exothermic oxidation occurs. The initial exothermic temperature ( ) of levopimaric acid, neoabietic acid, and dehydroabietic acid are 354.01, 353.83, and 398.20 K, the initial oxidation kinetics shows a second-order reaction, and the activation energies ( ) are 42.90, 58.05, and 46.60 kJ/mol, respectively. Peroxide concentration of three resin acids were determined by iodometry. The values of hydrogenated rosin, disproportionated rosin, hydrogenated rosin glyceride, and hydrogenated rosin pentaerythritol ester, the four rosin-modified resin, are 353.71, 348.32, 412.85, and 412.44 K. Levopimaric acid and neoabietic acid have higher oxidative reactivity and easily undergoes an oxidation reaction at lower temperature. Rosin-modified resins are stable and find it difficult to undergo oxidation reactions.
松香是一种可持续资源，主要由树脂酸组成。松香改性树脂广泛应用于胶粘剂、油墨、涂料等领域，其稳定性对产品的生产、储存和使用非常重要。使用加速量热仪（ARC）研究了三种树脂酸（左旋海松酸、新枞酸和脱氢枞酸）和四种松香改性树脂的热稳定性和反应活性。它们是稳定的，即使在氮气气氛下加热到200℃也不会发生放热反应，但在氧气气氛下不稳定。发现了氧化反应过程的机理：首先，树脂酸吸收氧气，然后发生放热氧化。左旋海松酸、新枞酸和脱氢枞酸的初始放热温度分别为354.01、353.83和398.20K，初始氧化动力学显示为二级反应，活化能分别为42.90、58.05和46.60kJ/mol。通过碘量法测定了三种树脂酸的过氧化物浓度。四种松香改性树脂氢化松香、歧化松香、氢化松香甘油酯和氢化松香季戊四醇酯的 值分别为353.71、348.32、412.85和412.44K。左旋海松酸和新枞酸具有较高的氧化反应活性，容易在较低温度下发生氧化反应。松香改性树脂是稳定的，难以发生氧化反应。
