Water-Contact-Angle Studies of Fabrics Radiation-Grafted with Methylhydrogensiloxane

The water-contact angles of the polymethylhydrogensiloxane (silicone)-grafted fabrics (wool, cotton, Vinylon, rayon, acetate, Tetoron, nylon, and silk) prepared by irradiation were measured and the results support the following conclusions: 1. For the same degree of grafting, the relation between the water-contact angles and the roughness factors (defined as the number of yarn crossover points per-unit-area) of various fabrics is linear. It is concluded that the surfaces of grafted fabrics are in the same state regardless of kinds of fabrics. 2. On fabrics of the same roughness the water-contact angles of grafted samples are greater by about 10° than those of the silicone-coated samples, which are padded with silicone, not irradiated, and heated. This fact can be explained by the hypothesis that the upheavals on the surface of a fabric are increased by radiation grafting. 3. By repeated washing with petroleum solvent, the water-contact angles of grafted fabrics decrease a few degrees after one washing and then do not change further even after repeated washing. This result suggests that the grafted silicone is “set” into a conformation which is not appreciably altered in spite of repeated solvent washing.