Torre del Greco, Italy
Torre del Greco, Italy

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Lacoste C.,University of Lorraine | Cop M.,University of Ljubljana | Kemppainen K.,VTT Technical Research Center of Finland | Giovando S.,Ledoga Silvateam | And 5 more authors.
Industrial Crops and Products | Year: 2015

Different kinds of tannin-based foams were developed in the recent past with fisetinidin/robetinidin-type tannins extracted from mimosa (Acacia mearnsii) or quebracho (Schinopsis lorentzi) bark; or procyanidin-type tannins from pine (Pinus pinaster and Pinus radiata). These biobased porous products revealed excellent properties similar to their synthetic counterparts in many applications. Norway spruce (Picea abies) bark is another large potential source of procyanidin-type tannins. In this study rigid and homogeneous foams were produced from purified tannins containing at least 80% of polyflavonoid condensed tannins. This paper deals with the study of spruce tannins reactivity for rigid foam formulations. Characterization results have point out their very good mechanical resistance (σ > 0.08. MPa), and low thermal conductivities (λ < 0.045 W/m/K) at low densities (d< 50kg/m3). © 2015 Elsevier B.V.

Cop M.,University of Ljubljana | Gospodaric B.,University of Ljubljana | Kemppainen K.,VTT Technical Research Center of Finland | Giovando S.,LEDOGA Silvateam | And 4 more authors.
European Polymer Journal | Year: 2015

Dielectric analysis, rheometry and differential scanning calorimetry were used in this study to analyse the curing process of tannin-based foams using mixture of maritime pine and Norway spruce tannins. The amounts of blowing agent (pentane) and catalyst (para-toluene sulphonic acid) were varied with the aim of monitoring the changes in the curing processes of foams. A thermal analysis carried out by differential scanning calorimetry revealed an almost finished reaction at the time of the peak temperature, occurring from the reaction of foaming, whereas conversion results derived from dielectric analysis and rheological tests indicated that curing process began after the occurrence of maximum temperature. With increased catalyst concentration, the start of curing process was accelerated, while a raised amount of pentane delayed the curing process. The curing process of the tannin-based foams was divided into three characteristic phases: the induction phase, the expansion phase, and the structure-strengthening phase. © 2015 Elsevier Ltd. All rights reserved.

Kemppainen K.,VTT Technical Research Center of Finland | Siika-aho M.,VTT Technical Research Center of Finland | Pattathil S.,University of Georgia | Giovando S.,Ledoga Silvateam | Kruus K.,VTT Technical Research Center of Finland
Industrial Crops and Products | Year: 2014

Norway spruce (Picea abies) is an important raw material for the forest industry in Nordic countries. The chemical composition and hot water extraction of spruce bark was studied to find out its potential as an industrial source of condensed tannins. Industrial bark was found to contain a high amount of wood (up to 21%), a sufficient amount of tannin for industrial extraction (10.7% of wood-free bark), and a high amount of non-cellulosic glucose, varying according to the felling season (7.7-11.5% of wood-free bark). Temperature had a major effect on the overall extraction yield. Selective extraction of only tannins or water-extractable carbohydrates was not possible. The extraction was scaled up to pilot-scale and an extract was produced having a promising 50% tannin content. Glycome profiling performed on bark and hot water extracts showed the presence of xyloglucan, pectic polysaccharides and arabinogalactan in bark. In addition the extracts were characterized using size exclusion chromatography and 31P nuclear magnetic resonance spectroscopy. Spruce bark appears to be a promising new source of tannins, however the high content of free, glycosidic, and polymeric sugars in the raw extract may need to be tackled prior to use in applications. © 2013 Elsevier B.V.

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