Toughened polylactic acid polymers and copolymers

Abstract

Toughened compositions of PLA and PLA copolymers are disclosed, which also have low tensile modulus values and greater elongation to break. These toughened compositions are prepared by blending PLA and PLA copolymers with poly-4-hydroxybutyrate, and copolymers thereof. Blending of poly-4-hydroxybutyrate with PLA and its copolymers has been found to impart advantageous properties to the resulting blend. These compositions, and objects formed from these compositions, have improved toughness and lower stiffness than polylactic acid polymers or copolymers alone.

We claim: 
     
         1 . A toughened polymer composition comprising poly-4-hydroxybutyrate homopolymer or copolymer thereof. 
     
     
         2 . The composition of  claim 1  wherein the stiffness of the composition decreases as the amount of poly-4-hydroxybutyrate homopolymer or copolymer in the composition is increased. 
     
     
         3 . The composition of  claim 1  wherein the elongation to break of the composition increases as the amount of poly-4-hydroxybutyrate homopolymer or copolymer in the composition is increased. 
     
     
         4 . The composition of  claim 1  further comprising plasticizers, nucleants, compatibilizers, therapeutic, prophylactic or diagnostic agents, radiolabelled substances, imaging agents, radiopaque markers, contrast agents, anti-oxidants, dyes, viscosity modifiers, and odor control agents. 
     
     
         5 . The composition of  claim 1  wherein the composition is used to make a textile, fiber, film or molded object. 
     
     
         6 . The composition of  claim 5  wherein the composition is oriented. 
     
     
         7 . The use of poly-4-hydroxybutyrate homopolymer or copolymer thereof to toughen a polymer composition. 
     
     
         8 . A medical device comprising the polymer composition of  claim 1 . 
     
     
         9 . The medical device of  claim 8  wherein the device is a suture, suture fastener, meniscus repair device, rivet, tack, staple, screw, bone plate, bone plating system, biocompatible coating, rotator cuff repair device, surgical mesh, medical textile, repair patch, sling, cardiovascular patch, tissue engineering scaffold, vascular graft, vascular closure device, catheter balloon, anti-adhesion device, drug delivery device, embolization particle, orthopedic pin, adhesion barrier, stent (including coronary stents, peripheral stents, carotid stents, biliary stents, gastroenterology stents, urology stents, and neurology stents), embolization coil, guided tissue repair/regeneration device, articular cartilage repair device, nerve guide, tendon repair device, intracardiac septal defect repair device (including, but not limited to, atrial septal defect repair devices and PFO closure devices and left atrial appendage (LAA) closure devices), pericardial patch, bulking and filling agent, vein valves, bone marrow scaffold, meniscus regeneration device, ligament graft, tendon graft, ocular cell implant, spinal fusion cage, imaging device, skin substitute, dural substitute, bone graft substitute, bone dowel, would dressing, or a hemostat.