2.1.1. Materials Commercially scoured-bleached of 100% cotton knitted single jersey structure fabric having areal density of 175 grams per square meter was collected from “HI-FASHION COMPOSITE TEXTILES LTD”, Joydebpur, Gazipur, Bangladesh for this experiment. Depicts the color co-ordinates of the fabric used for this research work.
2.1.2. Dyes & Chemicals Banana floral Stem (Musa sapientum) was collected from Santosh area, Tangail-1902, Bangladesh. Potassium Alum [Al2K2(SO4)4], Iron (II) sulfate heptahydrate (FeSO4.7H2O), Copper (II) sulfate pentahydrate (CuSO4.5H2O) and Stannous chloride pentahydrate (SnCl2.5H2O) procured from merck, Germany. The ISO Standard soaping agent without optical brighter, James heal, England were used for removing unfixed dye. All chemicals were laboratory grade and employed without any purification.
2.2.2. Natural Dye Extraction Dye used in this study was extracted according to our pervious investigations. Briefly, Banana (Musa sapientum) floral stems were detached from banana tree and washed. Fresh floral stem of the banana was cut into one meter pieces using cutlass and then pieces were sliced. Sap was extracted from floral stem by roller squeezer machine. Sap was filtrated by a nylon strainer and stored in plastic container. The sap was kept in a cool place and was prevented from sun rays to avoid evaporation and possible reaction for photo-catalytic degradation.
2.2.3. Mordanting Cotton fabric samples were subjected to pre-mordanting with metallic mordants by 5 g/L at 100? for 60 minutes. After soaking overnight, the mordanted samples were squeezed and air dried in flat dryer machine (MESDAN, Italy). The material to liquor ration had kept 1:20 in pre-mordanting action.
2.2.4. Dyeing The dyeing action was ended according to our previous study. Briefly, dyeing had carried out according to exhaust method by Infra-red lab sample dyeing machine (XIAMEN RAPID, China) at 1000 for 60 minutes. Then the dye bath was cooled at 400. Samples were washed at room temperature and air dried in flat dryer machine (MESDAN, Italy). Then soaping was performed for removing unfixed dye from the fabric surface by 0.5 g/L ISO standard soap at 80 0 for 10 minutes. For both dyeing and soaping, the material to liquor ration had kept 1:20.
2.2.5. FTIR-ATR Spectra FTIR-ATR spectra of scoured bleached cotton and dyed specimens were determined using FTIR spectrophotometer (PerkinElmer Spectrum Two, UK). Specimens were directly fitted on the respective place of Universal ATR of the machine for dye-fiber bonding characteristics evaluation.
2.2.6. Determination of Color Coordinates Value The color coordinates of the dyed samples were determined based on the CIE Lab system via dual beam reflectance Data-color Spectroflash (SF 650X, USA) keeping the setting: Illuminant D65, Medium area view, Specular included and CIE 1964 supple-mental standard observer (10° observer). Each sample was folded twice to give an opaque view with four plies and the color coordinates value was measured automatically.