Search Results (3)

Natural dyes offer a bio-based opportunity to support the attractive coloration of textile fabrics made from natural fibers like cotton, wool, hemp, and many other textile materials. They can be part of a strategy to realize fully bio-based textiles and clothing materials. In line with this statement, the following study investigates the use of wood extracts for dyeing cotton fabrics. Specifically, extract powders of logwood (Haematoxylon campechianum L.), brazilwood (Caesalpinia spp.), and quebracho wood (Schinopsis lorentzii) are used. The aim of the study is to evaluate which colorations can be obtained by the application of those wood extracts and what fastness properties are reached. For this, different modified process parameters and mordants are evaluated. The dyeing process is modified using different mordants based on iron and aluminum salts. These mordants are applied in pre-, meta-, or post-mordant procedures. The color and fastness properties of prepared textile samples are determined by spectroscopic measurements, color measurements, washing procedures, and a Xenotest for measuring the light fastness. Ultimately, it is shown that a broad range of colorations can be realized through different combinations of wood extracts and mordanting procedures. Notably, stronger color depths are reached with pre- and meta-mordanting compared to post-mordanting. Good wash fastness is obtained for some color shades. However, with post-mordanting, better wash fastness can be achieved. The light fastness of the realized samples is only moderate to low. In conclusion, it can be stated that dyes from wood extracts are excellent materials to dye natural fibers if they are combined with the right mordanting agent in pre- or meta-mordanting procedures. The present study is therefore a good proof-of-concept for the realization of fully bio-based colored textile materials. Full article

Neonatal calf diarrhoea (NCD) poses a significant health challenge in cattle herds, resulting in considerable economic losses and antimicrobial use. In response to the escalating threat of antimicrobial resistance, viable alternatives are imperative, aligning with European policies. This study evaluated the in-milk supplementation of the chestnut and quebracho tannin extract in preweaning calves on performance, diarrhoea occurrence, Cryptosporidium spp. shedding, protein digestibility, and intestinal health. Twenty newborn calves were divided, after colostrum administration, into two experimental groups for 30 days as follows: the control (CTRL) was fed with whole milk and solid feed, and tannins (TAN) were fed whole milk supplemented with 6/g day of tannin extract and solid feed. Faecal samples were collected on days 0, 3, 7, 14, and 30 for the evaluation of Cryptosporidium oocyst shedding and protein digestibility. Faecal consistency was evaluated during the sampling using the faecal score scale (0–3 scale, considering diarrhoea > 1). The results showed a significant reduction in diarrhoea frequency in the TAN compared to the CTRL group (p < 0.05) over 30 days of the trial. The prevalence of Cryptosporidium spp. was generally low (12%), considering all analysed samples. Protein digestibility revealed comparable values for the TAN and CTRL groups, suggesting that tannins did not negatively affect milk protein availability. In conclusion, the in-milk supplementation of 6/g day of the chestnut and quebracho tannin extract could be considered a valuable functional feed additive to decrease NCD occurrence, thus supporting animal health and decreasing antibiotic use in livestock. Full article

Tannin polyphenols are produced by plants to protect themselves against natural decay. It is expected that impregnating low-durable timber with tannin extracts of more durable species such as quebracho (Schinopsis balansae) will enhance the durability of the specimens. This biomimetic approach combined with the in situ polymerization of quebracho–hexamine formulations can be a valid alternative to synthetic wood preservatives. In this work, we aim to evaluate the impregnation mechanism as well as the impact of tannin and hardener concentration on the mechanical and leaching resistance properties of treated wood. Compression resistance, surface hardness and leaching resistance of four different common non-durable wood species: spruce (Picea abies), pine (Pinus spp.), poplar (Populus alba) and beech (Fagus sylvatica) impregnated with different concentrations of extract and hexamine are presented. The results show that the mechanical properties of tannin-impregnated timber are enhanced, especially for timber with lower densities. Tannin and hardener concentrations tendentially do not contribute significantly to further increase MOE (modulus of elasticity), MOR (modulus of rupture) and Brinell hardness. Similar results are also obtained when the specimens are tested against leaching: tannin is significantly more water-resistant when cured with hexamine, but higher amounts of hardener do not further improve its water resistance. These findings suggest that quebracho tannin–hexamine formulations are already effective at low concentrations (5 to 10% extract with 2.5 to 5% hexamine). Full article