Microstructure, morphology and strength of cotton yarns sized by collagen solution

For sizing cotton yarn before weaving, a new composition based on a biodegradable polymer—collagen, has been proposed. The detected changes in the FT-IR spectra of the yarn coated with a collagen solution indicate the obvious formation of new intermolecular hydrogen bonds between the primary and secondary amino groups of the collagen and the cellulose hydroxyl groups. The formation of such bonds contributed to the strengthening of the collagen film on the surface of cotton threads. SEM studies have shown a significant improvement in the microstructure of threads and the morphology of fibers compared with threads not sized and sized with starch. When sizing with a collagen solution, the diameter of the threads decreases by 14%, when sizing with a starch solution—by 18%. In cases of collagen sizing, along with bonding, compaction, a longitudinal orientation of the fibers is observed. The diameter of the cellulose fibers sized with collagen is in the range of 12–15 microns. Unlike starch, which fills the interfiber spaces and even penetrates into individual tubular fibers, collagen is evenly located only on the surface of the fibers. Improving the microstructure and morphology of cellulose fibers and threads when sizing with a collagen-based composition leads to a reduction in the consumption of sizing agent, an increase in the linear density of threads by 15–20%, an increase in breaking load by 25–35%, and a decrease in elongation at break by 15–20%.