2002 年 71 巻 2 号 p. 85-89
A Poly (vinyl alcohol) (PVA)/sericin blended plastic with a high tenacity and biodegradability was prepared by melting molding, and the relationship between the structure and the physical properties of the plastic was studied. For a sericin content rate of 2wt%, the stress and strain increase. At 5wt% these values decrease, and at 10wt% or above they increase again. FT-IR spectra of the sericin shows an absorption peak at an amide I absorption band having a β sheet (1620cm-1). The blended plastic at a sericin content rate of below 20wt% shows an absorption peak at an amide I absorption band having a random coil (1652cm-1). On the other hand, at a sericin content rate of a 30wt%, sample shows both absorption bands. Further, in the dependence of tan δ on temperature, a new peak of the sample with over 10wt% sericin content rate was observed. For a sericin content rate of above approximately 10wt%, the excessive sericin phase separates from PVA. In this case, the strain of the sample increases from plastically deformed phase-separated sericin and consequently, the stress increases. At a sericin content rate of 2wt%, a good degree of the blended complex developed.
