Yoshihiro Moteki

Strain-induced crystal modification in poly(tetramethylene succinate)

Abstract A new crystal modification induced by strain was found in uniaxially oriented fibres of poly(tetramethylene succinate). This new modification (β form) had a planar zigzag conformation of T10 (all trans) and a fibre identity period of 11.90 A, while the conventional α form had a T7GTḠ conformation and fibre identity period of 10.90 A. The solid-state crystal transition between α and β forms was reversible with respect to the successive application and release of strain.

Molecular weight distribution and branched structure of biodegradable aliphatic polyesters determined by s.e.c.-MALLS

Molecular weight distribution and mean square radius as a function of molecular weight for biodegradable aliphatic polyesters have been measured by multiangle laser light scattering (MALLS) detector for size exclusion chromatography (s.e.c.). The difference of their molecular structures is discussed in relation to the melt elasticity, which contributes to processability for extrusion coating and extrusion foaming. The evaluated values of branching ratio indicate the existence of long chain branched structures.