Deepali Rastogi

Low-surface-energy materials based on polybenzoxazines for surface modification of textiles

The benzoxazine monomers, 3-tert-butyl-3,4-dihydro-8-allyl-2H-1,3-benzoxazine (Benz-m) and 2,2-bis(3-methyl-3,4-dihydro-2H-1,3-benzoxazinyl) propane (Benz-b) were synthesized successfully using Mannich reaction. The formation of the monomer was confirmed by 1H NMR and FTIR spectroscopy. Both the monomers were coated onto cotton fabric and the fabric samples were then dried at 60°C and cured at 120°C for varying time period. During the curing process, monomer was converted to polybenzoxazine by ring-opening polymerization of oxazine ring. In the Raman spectra, presence of the characteristic absorption bands due to benzoxazine structure at 952, at 1037 and at 1348 cm−1 even after curing at 120°C for 2 h, suggested incomplete ring opening of benzoxazine to form polybenzoxazine. Also, the lack of durability of the finish to washing appears be due to the mild conditions of curing. Therefore, the application of Benz-b monomer was investigated on polyester (PET) fabric, which could be subjected to higher temperature however for shorter duration. The water and oil (ethylene glycol) repellency was measured to determine the hydrophobicity and oleophobicity of the finish on PET fabric. It was found that there was a marked improvement in the durability to laundry when compared with the treated cotton samples. This study provides a unique and easy method to prepare a low-surface-energy material through a simple thermal treatment procedure without using fluoro polymers or silicones.

Uttarakhand: A State Rich in Plant Fibers

ABSTRACT A diverse range of natural fibers is produced in many countries providing an important source of income for farmers and local communities. With the UN declaring 2009 as the Year of Natural Fibres, for the state of Uttarakhand the development comes as a fillip to its efforts toward promoting the use of natural fibers. Some of the commercially important natural fibers found in Uttarakhand are obtained from Sisal, Agave, Bhimal, Hemp, Jute, and Nettle. This review article describes some of the fiber-yielding plants of North West Himalayas with special reference to Uttarakhand. Many of the natural fibers described have been traditionally used by the rural communities; some of the traditional processing techniques employed have been described along with other natural fiber plant species that have the potential to provide alternative employment opportunities. This review article aims to compile the record of fiber-yielding plants of Uttarakhand, which will lead to increase the contribution of fiber-yielding plants in the rural economy and ecosystem of the state for achieving sustainable socioeconomic development.

Comparative Analysis of Selected Fluorocarbon-Based Oil and Water-Repellent Finishes on Textiles

Efficacy of selected commercially available fluorocarbon-based finish agents, such as Oleophobol (Huntsman) Fluoroguard SX and Fluoroguard VOX (Britacel Silicones) Nuva HPU (Clariant) TG-581 (Resil) Aquaphobe-SNT (Akkshata), on cotton and polyester fabrics was studied with respect to water and oil repellency. All the finish agents exhibited excellent water- and oil-repellent properties on both kinds of fabrics. The contact angle of water on the finished cotton and polyester fabrics was found to be ≥ 140° Nuva HPU and Oleophobol gave cotton very good protection against rain. Except Aquaphobe SNT, all other finishes imparted excellent oil-repellent property to cotton. In the case of polyester, maximum oil repellency was achieved with Aquaphobe SNT and Fluorogard SX. The finished polyester fabric showed minimal absorption and better resistance to penetration of water as compared to cotton when subject to the Bundesmann water repellency test. There was a slight yellowing of the cotton fabric after the application of Oleophobol finish. There was no effect on the strength of the fabrics. The effect of these finishes on the crease recovery angle and the bending length of cotton was not significant, However, the polyester fabric became slightly stiffer after the application of the finishes. The crease recovery angle of polyester also increased after the application of these finishes. The finished fabrics showed good water repellency up to 15 washes. Oil repellency showed deterioration after only 5 washes and was partially retained up to 15 washes. Both water and oil repellency became negligible after 30 washes.

Optimisation of Extraction and Dyeing Processes of Parmilia Usnea - Approach to Sustainable Craft Practise in Garhwal Himalayas

This paper examines the commercial viability of Parmelia usnea in small-scale dyeing units of Garhwal Himalayas and the traditional craft of the region. Physicochemical analysis of the plant was carried out in order to standardise the extraction method. The parameters studied were colour, physical appearance, pH, moisture, ash, acid-insoluble ash and water-soluble extractive value. Extraction and application of the dye were carried out and its conditions on wool were standardised by studying the effects of time, pH and temperature on extraction and also the effects of shades on exhaustion of the dye by a substrate.