Poly (p-dioxanone) and copolymers of p-dioxanone and glycolide were prepared．In order to increasing the plasticity and elasticity of these polymers

nonpoisonous plasticizers(phthalate) were added when they were spun into monofilament absorbable sutures．The polymers were physically admixed with plasticizers under stirring．The structure and properties of poly(p-dioxanone) sutures (PDS) and poly(p-dioxanone-co-glycolide) sutures (PDG) were determined by using DSC

X-ray diffraction and analyzed through examining the changes of strength

flexibility

macromolecular orientation and the level of crystallinity of the sutures．The introduction of plasticizers may lower the strength of intermolecular forces and increase the flexibility of the polymeric structure．When the plasticizer content was about 1％～4％

the PDS and PDG sutures exhibited improvement both in tensile strength and more flexibility．