Infrared studies of chain folding in polymers. IX. amylopectin and amylose

Abstract

Infrared studies of amylopectin complexes show the presence of the 1295-cm⁻¹ band which has been assigned to the regular fold conformation in amylose. Although no crystallinity was found on the basis of X-ray diffraction, regular folding does occur in amylopectin. These results indicate that the structure of the regular fold in amylopectin complexes is the same as in amylose. Aging studies showed an increase in the fold band intensity with time in both amylose and amylopectin complexes. Swelling of amylopectin films demonstrates that initial attack of the swelling agent occurs at the folded portions of the polymer.