TESAF Department, University of Padua, Viale dell'Università 16, 35020 Legnaro, Italy.
Department of Green Engineering and Circular Design, Salzburg University of Applied Sciences, Marktstraße 136a, 5431 Kuchl, Austria.
Molecules. 2023 Mar 20;28(6):2799. doi: 10.3390/molecules28062799.
This study examined the potential of hydrolysable tannin in comparison to condensed tannins for the production of furanic foams. The results indicate that chestnut tannin presents lower reactivity and requires a stronger acid for the polymerization. Additionally, foamability and density were found to be dependent on both surfactant concentration and tannin type, allowing lower densities for mimosa tannin and lower thermal conductivities for chestnut-based foams. Mimosa tannin was found to have the highest compression strength, followed by quebracho and chestnut, promising thermal conductivity of around 50 mW/m·K for 300 kg/m foams, which suggests that chestnut foams have the potential to performing highly when the density is reduced. Chemical analysis revealed that the methylene moieties of the furanics are non-specific and produces new covalent bonds with nucleophilic substrates: -OH groups and free-positions in the flavonoids. Overall, this study opens new perspectives for the application of hydrolysable tannins in polymer and material science.
本研究比较了可水解单宁和缩合单宁在呋喃泡沫制备方面的潜力。结果表明，栗木单宁的反应性较低，聚合需要更强的酸。此外，泡沫性能和密度取决于表面活性剂浓度和单宁类型，使得含羞草单宁的密度更低，而基于栗木的泡沫的热导率更低。研究发现，含羞草单宁的压缩强度最高，其次是奎拉乔和栗木，有望实现 300kg/m 泡沫的约 50mW/m·K 的热导率，这表明栗木泡沫在降低密度时具有优异的性能。化学分析表明，呋喃环的亚甲基部分是非特异性的，会与亲核底物（-OH 基团和类黄酮中的游离位置）生成新的共价键。总的来说，本研究为可水解单宁在聚合物和材料科学中的应用开辟了新的前景。
