Sepperer Thomas, Šket Primož, Petutschnigg Alexander, Hüsing Nicola
Forest Products Technology and Timber Construction Department, Salzburg University of Applied Sciences, Markt 136a, 5431 Kuchl, Austria.
Salzburg Center for Smart Materials, Jakob-Haringer Straße 2a, 5020 Salzburg, Austria.
Polymers (Basel). 2021 Sep 10;13(18):3058. doi: 10.3390/polym13183058.
With increasing demand of alternatives to oil-based lightweight materials, the development of tannin-based foams is getting more and more attention. In this paper, an alternative to traditionally used solvent-evaporation in the production of tannin-foams is presented. Mixing the tannin-furanic resin with different amounts of ionic and non-ionic surfactants at high agitational speed allows for the formation of highly porous, mechanically stable tannin-foams. Investigations on the influence of surfactant type and ingredient ratios on the foaming behavior and properties of the final foams were conducted. Materials obtained via this route do present extraordinary compression resistance (about 0.8 MPa), good thermal insulation (40 mW/m·K) and are suitable as a wastewater treatment agent at the end-of-life. It was shown that during mechanical blowing, homogeneous cross-sections and almost perfectly round pores form, leading to the high compression resistance. Investigations by means of Fourier transform infrared and C nuclear magnetic resonance spectroscopy show that the milder reaction environment leads to more linear poly(furfuryl alcohol)-tannin chains. This new type of tannin foam allows for use in various different fields of application ranging from durable building insulation to wastewater treatment.
随着对油基轻质材料替代品需求的增加，基于单宁的泡沫材料的开发越来越受到关注。本文介绍了一种在单宁泡沫生产中替代传统使用的溶剂蒸发法的方法。在高搅拌速度下将单宁-呋喃树脂与不同量的离子和非离子表面活性剂混合，可以形成高度多孔、机械稳定的单宁泡沫。研究了表面活性剂类型和成分比例对最终泡沫发泡行为和性能的影响。通过这种方法获得的材料具有出色的抗压强度（约0.8兆帕）、良好的隔热性能（40毫瓦/米·开尔文），并且在使用寿命结束时适合用作废水处理剂。结果表明，在机械发泡过程中，形成了均匀的横截面和几乎完美的圆形孔隙，从而导致了高抗压强度。通过傅里叶变换红外光谱和碳核磁共振光谱进行的研究表明，较温和的反应环境会导致更多线性的聚（糠醇）-单宁链。这种新型的单宁泡沫可用于从耐用建筑隔热到废水处理等各种不同的应用领域。
