Abstract:

In order to enhance the application property of starch used as sizing agent, starch-grafted 3-acrylamidopropyl trimethylammonium chloride (S-g-PATC) samples with different grafting ratios were synthesized by changing the mass ratio of weight ratio of 3-acrylamidopropyl trimethylammonium chloride (ATC) to acid-thinned starch (ATS). The molecular structures of ATS and S-g-PATC were characterized by Fourier transformation infrared spectrometry. The swelling power of S-g-PATC and the mechanical properties, the degree of crystallinity, the moisture regain of its film and the time required for breaking its film in water were studied. The results show that graft modification of starch by quaternary ammonium cation increases the swelling power of starch, reduces the degree of crystallinity of film, and enhance the moisture regain of film and the time required for breaking film in water. The graft modification of starch by quaternary ammonium cation enhancse the toughness of film, and improve the rigid and brittle properties of starch film and the desizing property of starch used as sizing agent. When the grafting ratio is increased from 2.8% to 10.6%, the breaking elongation of S-g-PATC film is increased from 2.56% to 3.92%, while the tensile strength is decreased from 28.04 MPa to 24.27 MPa.

Key words: puaternary ammonium cation, grafted starch, sizing agent, film property, grafting ratio