Novel and durable flame-retardant modification based on the Schiff base and Pudovik reaction for wool fabric

Durable and formaldehyde-free flame-retardant (FR) modification of wool fabric using phosphorous compounds is of great interest. In this study, Schiff base imine groups were firstly introduced onto wool fiber through aldehyde-amine condensation between p-hydroxybenzaldehyde and wool fiber. Then, an efficient and durable FR wool fabric was fabricated by incorporating diethyl phosphite (DEP) into a Schiff base intermediate via the Pudovik reaction. The potential reaction mechanism among p-hydroxybenzaldehyde, DEP and wool fiber was explored. The thermal stability, smoke generation ability, FR ability and washing durability of the modified wool fabric were studied. The FR modification significantly increased the thermal resistance of wool fabric and suppressed smoke generation by half. The wool fabric modified by 20 g/L DEP was able to self-extinguish during the burning test, suggesting the higher FR efficiency of the DEP-incorporated Schiff base system. The modified wool fabric still self-extinguished after 20 commercial launderings, which is attributed to the covalent grafting of DEP onto wool fiber. Char residue analyses revealed the condensed charring FR mechanism of the DEP-incorporated Schiff base system on wool. This work provides a novel approach to prepare efficient and durable FR functional wool fabric via the Schiff base reaction and Pudovik reaction among p-hydroxybenzaldehyde, DEP and wool fiber.

Waterless sterilization and cleaning of sheep wool fiber using supercritical carbon dioxide

There is increasing concern regarding the existing sheep wool processing technology in the textile industry owing to the enormous volume of toxic effluents generated. The application of supercritical carbon dioxide (scCO2) in sheep wool processing is cleaner and increases wool fiber production while avoiding toxic effluent generation. scCO2 is a novel clean technology that can be utilized in sheep processing for sterilization, cleaning, and drying sheep wool at the same time. In the present study, scCO2 was used to treat sheep wool with varying pressure, temperature, and treatment time. These parameters influence the scCO2 treatment of sheep wool fiber through the inactivation of microorganisms and improvement of the whiteness index. The identification of bacteria in sheep wool was carried out based on biochemical analysis by molecular means, using 16s rRNA sequencing. It was found that scCO2 completely inactivated the microorganisms present in sheep wool and potentially enhanced the percentage whiteness index at the highest pressure of 30 MPa, temperature of 80°C, and treatment time of 80 min. Several analytical methods were employed to assess the physicochemical, thermal, and morphological properties of untreated and scCO2 treated sheep wool fibers. The results show that scCO2 effectively removes the impurities and completely inactivates the microorganisms present in sheep wool. The findings of the present study reveal that scCO2 can be utilized as an alternative treatment technology for sheep wool processing in the textile industry.

Study on the Dry-Cleaning Process of Mink Fur Based on Subcritical Solvent

It is significant to apply environmentally benign technology to fur processing. In this paper, subcritical extraction with n-pentane was used to dry clean mink fur and the effect on the quality of mink fur was studied. The dispersion degree of the leather fibers and the morphology of the wool fiber were characterized with SEM, the mechanical properties, shrinkage temperature and oil content left in fur were determined and analyzed. The results showed that the fibers of mink fur were well separated and no excess lipids in the fibers or on the surface of mink fur and the hair of the mink fur is not damaged. The tensile strength and elongation of mink fur show slight increase respectively, and the shrinkage temperature of mink fur that was treated by subcritical solvent was significantly increased compared with that of the mink fur treated with tetrachloroethylene by conventional dry cleaning method.

Role of Sulfur Metabolism Gene and High-Sulfur Gene Expression in Wool Growth Regulation in the Cashmere Goat

Sulfur, an essential mineral element for animals, mainly exists in the form of organic sulfur-containing amino acids (SAAs), such as cystine, methionine, and cysteine, within the body. The content, form, and structure of sulfur play an important role in determining the wool fiber quality. In addition, keratin-associated proteins, one of the most crucial wool fiber components, are rich in SAAs. However, sulfur metabolism from the blood to the skin and hair follicles remains unclear. In this study, we analyzed high-sulfur protein gene and sulfur metabolism genes in the cashmere goat and explored the effects of melatonin on their expression. In total, 53 high-sulfur protein genes and 321 sulfur metabolism genes were identified. We found that high-sulfur protein genes were distributed in the 3–4 and 144M regions of chromosome 1 and the 40–41M region of chromosome 19 in goats. Moreover, all year round, allele-specific expression (ASE) is higher in the 40–41M region of chromosome 19 than in the other regions. Total of 47 high-sulfur protein genes showed interaction with transcription factors and cofactors with ASE. These transcription factors and cofactors were inhibited after melatonin implantation. The network analysis revealed that melatonin may activate the sulfur metabolism process via the regulation of the genes related to cell energy metabolism and cell cycle in the skin, which provided sufficient SAAs for wool and cashmere growth. In conclusion, our findings provide a new insight into wool growth regulation by sulfur metabolism genes and high-sulfur protein genes in cashmere goats.