Grape skins and seeds rich in polyphenolic compounds are low-value byproducts from the wine-making. The valorization of such byproducts is of great significance. This work presented a novel application of grape seed proanthocyanidins (GSPs) in the dyeing and flame-retardant and antibacterial treatment of silk. The study on adsorption isotherms revealed that multiple interactions occurred between GSPs and silk, including electrovalent bonding, hydrogen bonding, and van der Waals forces. The color depth of silk mainly depended on temperature and GSP concentration. Dyed silk had acceptable color fastness to washing, rubbing, and perspiration. Postmordanting could improve light fastness. Changes in the tensile strength and flexural rigidity of dyed silk were in an acceptable range. A low concentration of GSPs imparted a durable antibacterial function to silk. The biggest highlight of this study was the improved flame retardancy of silk caused by GSP dyeing. GSPs increased the thermal stability and charring ability of silk at high temperatures, and their flame-retardant action worked in the solid phase. Mordanting had no substantial impact on the flame-retardant and antibacterial functions of dyed silk. The present research reveals that the valorization of GSPs for silk processing is feasible.

中文翻译：

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葡萄籽原花青素：用于丝绸的新型着色剂，阻燃剂和抗菌剂

富含多酚化合物的葡萄皮和种子是酿酒中的低价值副产品。这种副产物的增值具有重要意义。这项工作提出了葡萄籽原花色素（GSPs）在丝绸的染色，阻燃和抗菌处理中的新应用。吸附等温线的研究表明，GSP与丝绸之间发生了多种相互作用，包括电价键，氢键和范德华力。蚕丝的色深主要取决于温度和GSP浓度。染色后的丝绸具有耐洗，耐擦和耐汗的​​色牢度。晒后可以提高耐光性。染色丝的拉伸强度和抗弯刚度的变化在可接受的范围内。低浓度的GSP赋予丝绸持久的抗菌功能。这项研究的最大亮点是由于GSP染色而提高了丝绸的阻燃性。GSP在高温下提高了丝绸的热稳定性和炭化能力，其阻燃作用在固相中起作用。Mordanting对染色丝的阻燃和抗菌功能没有实质性影响。目前的研究表明，用于丝绸加工的GSPs的增值是可行的。Mordanting对染色丝的阻燃和抗菌功能没有实质性影响。目前的研究表明，用于丝绸加工的GSP的增值是可行的。Mordanting对染丝的阻燃和抗菌功能没有实质性影响。目前的研究表明，用于丝绸加工的GSPs的增值是可行的。