The effect of diethylene glycol dimethacrylate graft treatment on the structural changes of the silk fibers was examined in relation to the graft yield on the basis of the results of scanning electron micrograph photographs (SEM)

infrared spectroscopy(IR)

birefringence(Δn)

X-ray diffraction and amino acid analysis．The diethylene glycol dimethacrylate grafted silk fibers with different amounts of graft yield showed a substantial decrease of the amino acid composition of Tyr．

His．

Ser．

Arg．The other amino acid residues remained essentially unchanged or showed only slight changes

so

the diethylene glycol dimethacrylate exhibited reactivity toward Tyr．

His．

Ser．

and Arg．of silk fibers．X-ray diffraction patterns of silk fibers suggested that the diethylene glycol dimethacrylate grafting does not affect directly the crystalline regions

but causes a decrease of molecular orientation in the amorphous regions．Birefringence(Δn) of silk fibers decreased by grafting with the diethylene glycol dimethacrylate．When the graft yields ale more than 35％

the surface of silk fibers showed the presence of several granules

consisting of the diethylene glycol dimethacrylate polymers

and the cross-sectional area of silk fibers showed the appearance of separating fiber．The IR of the grafted silk fibers showed absorption bands at 1651 cm-1 (amide Ⅰ) and 1520 cm-1 (amide Ⅱ) assigned to the β structure of the silk fibroin and additional bands at 1732

1134 and 1041 cm-1

characteristic of the spectra of the diethylene glycol dimethacrylate polymer. Additionally

the IR of the grafted silk fibers showed overlapped absorption bands due to the molecular conformation of this fiber and the diethylene glycol dimethacrylate polymer

giving evidence that the the diethylene glycol dimethacrylate graft occurred inside the fiber matrix. Thus the theoretical basis is provided for the silk chemical finishes or modification.