Influence of Microwave Radiation on Dyeing of Bio-mordanted Silk Fabric using Neem Bark (Azadirachta indica)-Based Tannin Natural Dye

ABSTRACT

The utilization of bio-mordants to make natural coloring process more eco-friendly is gaining worldwide fame, whereas the addition of microwave treatment has added value to the extraction of colorant under mild conditions. The Current study has been undertaken to isolate tannin from neem (Azadirachta indica) bark under the impact of microwave radiation for the dyeing of mordanted (chemical and bio) silk fabric. For this purpose, the extraction of colorant (tannin) has been carried out in various media and dyeing variables have been optimized. For making the process more sustainable and clean, extracts ofbio-mordants such as turmeric (Curcuma longa), henna (Lawsonia inermis), pomegranate (Punica granatum) and acacia (Acacia nilotica) have been employed at given conditions. It is found that microwave radiation for 2 min. to acidified methanolic extract of 2 pH obtained from 6 g powder has given good color strength in irradiated silk when it is used to dye at 75°C for 65 min. by employing 3 g/100 mL of Glauber’s salt the as exhausting agent. It is concluded that microwave treatment has not only enhanced the extraction of tannin from neem bark but also improved the color characteristics under low conditions.

GRAPHICAL ABSTRACT

摘要

利用生物媒染剂使天然着色过程更加环保，在世界范围内得到了广泛的应用，而微波处理的加入对温和条件下的着色剂提取具有附加价值. 在微波辐射下，从印楝(Azadirachtaindica)树皮中分离出鞣质，用于化学和生物真丝织物的染色.为此，在各种介质中进行了着色剂（鞣质）的提取，并对染色参数进行了优化. 为了使该工艺更具可持续性和清洁性，在一定条件下，采用了姜黄（Curcuma longa）、指甲花（Lawsoniainermis）、石榴（Punicagranatum）和金合欢（Acacia nilotica）等生物媒染剂提取物。结果表明，用3g/100ml的Glauber盐作抽提剂，在75℃下进行65分钟的染色时，6g粉末经微波照射2分钟，得到2pH的酸化甲醇提取物，对辐照后的蚕丝具有良好的显色强度.结果表明，微波处理不仅提高了印楝皮单宁的提取率，而且在较低的条件下改善了印楝皮的颜色特性.

KEYWORDS:

• Bio-mordants
• chemical mordants
• microwave. neem bark
• silk
• tannin

关键词:

• 生物媒染剂
• 化学媒染剂
• 微波
• 印楝树皮
• 丝绸
• 单宁

Acknowledgments

We are thankful to the Society of Dyers and Colourists (SDC), UK, for providing the bursary to conduct a part of PhD studies. Authors are also thankful to Mr Zafar Iqbal, Manager Noor Fatima Fabrics Faisalabad, Pakistan, as well as Mr Muhammad, Abbas Chief Executive, Harris Dyes and Chemicals Faisalabad, Pakistan, for technical and scientific guidance at lab scale and for providing us the facilities of fastness testers to conduct a part of this PhD studies.

Additional information

Funding

This work was supported by the Society of Dyers and Colorist (SDC), Bradford UK.