Amphipathic Starch with Phosphate and Octenylsuccinate Substituents for Strong Adhesion to Cotton in Warp Sizing

The objectives of this work were to survey the effect of amphipathic modification of starch on the adhesion to cotton fibers for improving the adhesion of starch to cotton in warp sizing. The amphipathic starch (AS) with oleophilic octenylsuccinate and hydrophilic phosphate substituents was prepared by the phosphorylation with sodium tripolyphosphate (STP) followed by the octenylsuccinylation with 2-octenylsuccinic anhydride (OSA). Two series of AS samples with differential total degrees of substitution (DSt) and substituent ratios of phosphates to octenylsuccinates were evaluated by fourier transform infrared (FTIR) analysis, degree of substitution, adhesion to cotton and surface tension. The adhesion of the starch to fibers was investigated using a legal method (FZ/T 15001-2008). The FTIR spectra revealed that octenylsuccinates and phosphates have been attached to the backbones of the starch. The amphipathic modification of starch with STP and OSA was an effective method to enhance the adhesion of corn starch to cotton. The strong adhesion of the AS to cotton was attributed to the reduced surface tension arisen from oleophilic octenylsuccinate and hydrophilic phosphate substituents and increased steric hindrance of the substituents introduced onto starch. The investigation showed that the improvement in the adhesion of the starch after amphipathic modification could be buttressed by the tensile strength of cotton yarns sized with AS. It was found that the AS was desizable and showed satisfactory desizing efficiency in oxidant desizing. Based on the adhesion, reaction efficiencies, and desizability, the AS with a total DSt of 0.033 and a substituent ratio of DS(p)0.014/DS(o)0.032 showed potential for use in warp sizing.