BIOMASS EXTRACTION FROM Cocos nucifera HUSK- AN AGRO-ORGANIC WASTE FOR COLORATION OF SILK FABRIC
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Date
2023
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Abstract
In present years, natural dyes have gained popularity as a safer alternative to
dangerous synthetic colors. Eco-friendly, environment-safe natural dyeing techniques and
products are today’s entail for textiles. Natural coloring substances are now growing trends
for their use all over the world because of health hazards and toxicity problems created by
synthetic dyes.
Considering the growing importance of natural dyes all over the world, the present
investigation entitled “Biomass extraction from Cocos nucifera husk- An agro-organic waste
for coloration of silk fabric” was undertaken to assess the following objectives:
1. Extraction and optimization of dyeing conditions of coconut husk dye on mulberry
silk fabric.
2. Surface enhancement of dyed fabric using eco-printing method.
3. Evaluation of properties of dyed and printed fabrics.
To carry out the study, coconut (Cocos nucifera) husks dye was used as a natural dye
to develop variety of natural colors on mulberry silk fabric using alum and gallnut as
mordants. For extraction of dye, an aqueous medium was employed with an optimum
wavelength of 570 nm which showed the highest (1.62%) absorbency value.
Pre-treatment method such as degumming was carried out for the mulberry silk
fabric to enhance the lustre, color and texture of the dyed silk fabric. Based on the objectives
different dyeing parameters were optimized such as extraction medium, extraction time, dye
concentration, dyeing time, mordant concentration, mordanting time and mordanting
methods. The optimum dye extraction time was 60 min. Dyeing process was carried out
keeping the material to liquor ratio 1:30 at a constant temperature of 70ºC for 45 min. The
optical density values of the dye solution before and after dyeing were carried out to find out
absorption percentage (%). The mordant concentration, mordanting time and mordanting
methods were also optimized to get better shades. Brown, light brown and medium to deep
brown colors were obtained from dyed, alum mordanted and gallnut mordanted silk fabric,
respectively. The physical and colorfastness properties of the fabrics were evaluated.
As regards physical properties, the dyed with and without mordant and mordanted
eco-printed silk fabrics were found to be increased in terms of fabric count (Ne), thickness
(mm), weight (g/m2), crease recovery (angle), stiffness (cm), elongation (%) compared to
control fabric. However, the decreased in tensile strength (N), moisture regain (%) and
wicking height (cm) were found in dyed with and without mordant as well as mordanted
eco-printed silk fabrics. From the test results, it can be concluded that all the samples of silk
fabrics showed satisfactory results and wide scope of development of textile materials. The
colorfastness to sunlight, washing, crocking, pressing and perspiration were assessed for
dyed and eco-printed silk fabrics in terms of color alteration and all the samples found to be
good to very good fastness and there was slightly to negligible staining of the color.
The morphological and structural characteristics of control and dyed fabrics were
assessed using SEM, FTIR and XRD analysis. SEM images of control and dyed silk fabrics
revealed that slightly rough surface with irregularities, cylindrical shapes, presence of fibrils,
nodes. The control and alum mordanted dyed sample showed smoother and more uniform
surface than the without mordanted and gallnut mordanted samples. FTIR spectrum of the
control and dyed silk fabric samples showed the presence of various components such as
alkenes, aliphatic amines, alcohols, carboxylic acids, esters, ethers, phenol ring, 1º amines,
alcohols, phenols. The crystallinity region of the fabrics was identified by XRD analysis and
alterations in the crystallinity structures of dyed silk fabrics compared to control were
discovered.
The Ultraviolet protection properties of control, dyed with and without mordanted
silk fabrics were evaluated and found that the Ultraviolet protection properties of dyed
fabrics were more as compared to control fabric. Both alum and gallnut mordanted fabrics
showed good UV protection. However, control and without mordanted dyed fabric showed
very poor UV protection.