Abstract—The pretreatment processes prior to dyeing which were the scouring and bleaching, for the knitted fabric of PLA/cotton blend were studied comparing with the 100% cotton and PLA fabrics. These two pretreatment processes were studied in a sequence (scouring followed by H₂O₂ bleaching) and altogether in the one-bath process. The scouring process of the blended fabric was compared when the different scouring agents were employed (NaOH, Na₂CO₃ and pectinase enzyme). The two-bath and one-bath scouring/bleaching processes had a signified effect on the strength of the fabrics because the pretreatment processes typically used for cotton are in the alkaline condition which can deteriorate the PLA fiber. Therefore, the pretreatment conditions for the PLA/cotton blended fabric needed to be optimized to avoid fiber damage. From the research, it was observed that the pretreatments for the blended fabric, which was to enter the pale-shade dyeing, were scoured using 10%owf pectinase (60°C, 60 min) as it enhanced a satisfactory water absorbency to the fabric without causing any adverse effect on the fabric strength. For deep-shade dyeing, the blended fabric should undergo the one-bath scouring/bleaching with 7%owf H₂O₂ (100°C, 60 min) which yielded a water absorbency and whiteness on the fabric to a standard level and the resulting fabric strength was highest and this one-bath pretreament was the time-saving process.

Index Terms—Pretreatment, knitted fabric, scouring, bleaching, PLA/cotton blend

I. Na Phatthalung is with the Department of Textile Science, Faculty of Agro-Industry, Kasetsart University, Bangkok, 10900, Thailand (e-mail: Issara_5415@hotmail.co.th).
P. Sae-be is with the Department of Textile Science, Faculty of Agro-Industry, Kasetsart University, Bangkok, 10900, Thailand (corresponding author, phone: 66-2-5625065; fax: 66-2-9428663; e-mail: fagipts@ku.ac.th ).
J. Suesat is with the Department of Textile Science, Faculty of Agro-Industry, Kasetsart University, Bangkok, 10900, Thailand (e-mail: Jantip.s@ku.ac.th ).
P. Suwanruji is with the Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand (e-mail:fscipjs@ku.ac.th).
N. Soonsinpai is with the Department of Textile Science, Faculty of Agro-Industry, Kasetsart University, Bangkok, 10900, Thailand (e-mail: nookpete@hotmail.com).

Cite: Issara Na Phatthalung, Porntip Sae-be, Jantip Suesat, Potjanart Suwanruji, and Nantaporn Soonsinpai, "Investigation of the Optimum Pretreatment Conditions for the Knitted Fabric Derived from PLA/Cotton Blend," International Journal of Bioscience, Biochemistry and Bioinformatics vol. 2, no. 3, pp. 179-182, 2012.