Defining the physical structure and properties in novel monofilaments with potential for use as absorbable surgical sutures based on a lactide containing block terpolymer

Monofilaments of a block terpolymer of l-lactide, ɛ-caprolactone and glycolide have been melt spun for potential use as absorbable surgical sutures. As-spun fibres of the terpolymers produced by melt spinning were elastic, amorphous and isotropic. A two-stage process involving hot drawing was employed to enhance their mechanical properties. WAXS and SAXS results coupled with DSC demonstrated that hot drawing leads to an orientated amorphous matrix containing small highly aligned crystals. Hot drawing was carried out at a range of temperatures using the highest possible draw rate commensurate with maintaining continuity of the fibre. A novel WAXS analysis based on a spherical harmonic analysis allowed a separation of the scattering into three components: oriented crystalline, oriented amorphous, and an isotropic amorphous. There is a steady increase in the fraction of oriented crystalline material with increasing hot draw temperature, although the level of crystallinity is ultimately limited by the statistical nature of the terpolymer. The material shows highly promising potential properties for use as a monofilament suture.