Enhanced Mechanical Performance of Poly(l‐Lactide)‐Based Degradable Materials by Solid‐State Drawing Process

A convenient solid‐state drawing process is developed for the first time to simultaneously improve the mechanical properties of poly( l ‐lactide) (PLLA) and poly( l ‐lactide‐glycolide‐trimethylene carbonate) terpolymer (PLGT) via crystallization and molecular chain orientation. PLLA demonstrates a breaking strength of 164 MPa and a strain of 36%; while the drawn PLGT exhibits a higher breaking strength of 263 MPa and a strain of 55%. Such remarkable enhancement in mechanical properties was attributed to the transition of the crystal structure of PLLA segments from densely packed α phase to loosely arranged α ′ phase, the transition of spherulites to interlocking shish‐kebab crystals, and the orientation of amorphous molecular chains. Therefore, tailoring phase structure in totally degradable PLLA‐based copolymers provides a novel strategy to enhance their mechanical performance for uses as biomaterials.