Effects of Molecular Structure of Carboxyl-Containing Vinyl Monomers on Sizing Properties of Feather Keratin Graft Copolymer

In order to study the effects of molecular structure of carboxyl-containing vinyl monomers on application performance of feather keratin (FK) graft copolymer for warp sizing, three kinds of carboxyl acids, i.e. acrylic acid (AA), methacrylic acid (MAA), and itaconic acid (IA), were grafted onto molecular chains of FK through initiation of K 2 S 2 O 8 -NaHSO 3 redox system. FK- g -PAA, FK- g -PMAA, and FK- g -PIA with similar grafting ratios around 31 % were prepared as sizing agents. Major sizing properties of the three grafted keratins were studied in terms of water-solubility, apparent viscosity, contact angles of sizing paste on cotton fibers, mechanical properties of sizing film, and adhesion to fibers. It was found that sizing properties of the grafted FK strongly depended on molecular structure of the carboxyl-containing vinyl monomers. In view of overall performance of the grafted keratin sizes, the most appropriate carboxyl-containing vinyl monomer should be AA.