Authors S Wazed Ali, Roli Purwar*, M Joshi, S Rajendran
Increased global competition in developing advanced textile based medical products has created many challenges for textile researchers and industrialists. The rapid growth in medical and wellness textiles has evolved many opportunities for the application of innovative functional finishes. Antimicrobial 29 finished textiles with improved functionality find a variety of applications such as infection control, other health and hygiene applications In the last few decades, research has been carried out in developing novel technologies to produce enhanced antimicrobial activity on textiles by using different synthetic antimicrobial agents such as triclosan, metal and their salts, organometallics, phenols and quaternary ammonium compounds (Windler et al. 2013). Although the synthetic antimicrobial agents are very effective against a range of microbes and provide a durable effect on textiles, they are a cause of concern due to the associated side effects and ecological problems such as water pollution. Hence, there is a need and demand for antimicrobial textiles based on eco-friendly agents which not only help to reduce the ill effects associated due to microbial growth on textile materials but also comply with the statutory requirements imposed by the regulating agencies. There is a vast resource of natural products with active antimicrobial ingredients amongst which the plant-based products cover a major range. Healing power of some of the plant materials has been well-known and used since ancient times worldwide. Although there are many natural products rich in antimicrobial agents, only chitosan and natural dyes have been widely used as potential antimicrobial agents for textile application. A systematic study on integrating neem seed and bark extracts to cotton and cotton/polyester blend has been reported. The major challenges in the application of natural products for textile application are most of these plant materials are complex mixtures of several compounds and also the composition varies in different species of the same plant. The durability, shelf life and antimicrobial efficiency of natural products are other issues of concern. To address these issues further research should be carried out in bioactive textiles made from natural products, to make it a viable alternative to synthetic product based antimicrobial textiles. Aloe barbadensis Miller is mostly used because of its excellent medicinal properties. In a study it was found that the Aloe leaf contains over 75 nutrients and 200 active compounds, including 20 minerals, 18 amino acids and 12 vitamins. The main components of these constituents are glycoprotein, barbaloin, aloe-emodin, emodin, mannose-6-phosphate, polysaccharides, acemannan, aloesin, etc. The active ingredients of Aloe vera gel have wide range of activities such as moisturizing, anti-inflammatory, antibacterial, antifungal, antiviral agent, antiodor, etc. They also possess UV protective, antiprotozoal and wound healing properties. Wound healing property of Aloe vera has been extensively studied. Glycoprotein and mannose-6-phosphate present in Aloe vera have good wound healing property. Polysaccharides and barbaloin in Aloe gel are mainly responsible for their antimicrobial activity. The antifungal and antibacterial properties of Aloe vera can be exploited for medical textile applications, such as wound dressing, suture and other bioactive textiles. The combined activities of Aloe vera, chitosan and curcumin on cotton, wool and rabbit hair with their different concentrations by exhaust method have been studied In the present work an attempt has been made 79 to finish the cotton textiles with Aloe vera gel along with BTCA cross-linking agent. The finished fabric was characterized by Fourier transform infrared spectroscopy (FTIR) to understand the mechanism of attachment of Aloe vera gel with cotton substrate in presence of BTCA cross-linking agent. The antibacterial property of Aloe vera gel finished fabric was evaluated against both Gram-positive and Gram-negative bacteria. The mechanism of destruction of both Gram-positive and Gram negative bacteria by Aloe vera gel has also been established. Finishing treatment, Pad-dry-cure method, Wash fastness, Antibacterial activity of Aloe vera treated fabric, Aloe vera treated fabrics was quantitatively evaluated by shake flask method, Performance Properties of Finished Fabrics, tensile, testing of fabric, carboxylic acid (BTCA) chemically reacts with the functional group of cotton and formed an ester linkage, treated cotton fabric with BTCA in presence of sodium dihydrogen phosphate(I) monohydrate as catalyst. FTIR spectra of treated fabric showed band at the wavelength 1725 cm1 which represents the ester carbonyl group confirms the covalent bond between the cellulose and BTCA. The intensity of this band is a measure of total quantity of ester group created in the finished cotton fabrics, Aloe vera treated fabric showed a little shift of ester peak from 1731.54 177 cm-1 to 1724.35 cm-1 and also the intensity of this peak is lowered as compared to that of only BTCA treated fabric . This indicates a decrease in the average number of ester groups formed in presence of Aloe vera. The lower intensity peak of Aloe vera with cross linking agent treated cotton is due to the interaction of Aloe vera active compounds with some of the hydroxyl (-OH) groups of the cotton and also interaction with the free COOH groups of carboxylic acid molecules which are supposed to form ester linkage with cotton in absence of Aloe vera compounds. Hence, the extent of degree of direct chemical cross linking between cotton and carboxylic acids via ester linkage is effectively less in Aloe vera treated samples as some of the OH groups of cotton are actively occupied by some of the OH groups of Aloe vera ingredients. Thus active ingredients of Aloe vera containing OH groups in their chemical structure can easily form H-bonding with the either OH groups of cellulose backbone or chemically react with the carboxylic acid during curing process. In some cases the carboxylic acid may act as a bridge between the active ingredients of Aloe vera and cotton molecules. Similar results obtained when cotton fabric was finished with neem active ingredients along with glyoxa/glycol cross-linking agent, Aloe vera treated fabric showed tremendous reduction in bacterial adhesion. The active ingredients of Aloe vera gel act as an effective bactericidal agent on to the fabric and inhibits the growth of both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria. With increase in concentration of Aloe vera (up to 7%) the bacterial reduction increased up to 99%. This may be due to the enhanced weight addon% of the aloe active ingredients on the fabric with increasing Aloe vera concentration. It was also observed that only BTCA treated fabric showed bacteria retention of around 70%. The durability of the antibacterial activity of the Aloe vera treated cross-linked fabric was evaluated after repeated washing. It was found that the antibacterial activity retains more than 70% up to 5 machine washes and more than 50% even after 8 machine washes although there is a sharp reduction in antibacterial activity. As active ingredients of Aloe vera gel also contain OH groups like cellulosic molecules, and also forms same types of bonds among BTCA and cotton structure, they are going to lose during washing. Thus antibacterial activity is going down due to removal of active ingredients along with the removal of BTCA. This also confirms that the active ingredients of Aloe vera gel are chemically / physically linked with the BTCA.
