title: Synthesis, characterization and melt spinning of a block copolymer of L-lactide and epsilon-caprolactone for potential use as an absorbable monofilament surgical suture.
abstract: This paper describes the synthesis and characterization of a block copolymer of L-lactide (LL) and epsilon -caprolactone (CL) and its subsequent melt spinning into a monofilament fiber. The synthesis reaction was a two-step process. In the first step, an approximately 50:50 mol% random copolymer, P(LL-co-CL), was synthesized via bulk copolymerization of LL and CL. This first-step prepolymer then became the macroinitiator in the second-step reaction in which more LL monomer was added to form a block copolymer, PLL-b-P(LL-co-CL)-b-PLL. Both the prepolymer and block copolymer were characterized by a combination of analytical techniques comprising dilute-solution viscometry, GPC, 1H and 13C NMR, DSC and TG. The block copolymer was then processed into a monofilament fiber using a small-scale melt spinning apparatus. The fiber was spun with a minimum amount of chain orientation and crystallinity so that its semi-crystalline morphology could be constructed under more controlled conditions in subsequent off-line hot-drawing and annealing steps. In this way, the fiber's tensile properties and dimensional stability were developed, as indicated by the changes in its stress-strain curve. The final drawn and annealed fiber had a tensile strength (>400 MPa) approaching that of a commercial PDS II suture of similar size. It is considered that this type of block copolymer has the potential to be developed further as a lower-cost alternative to the current commercial monofilament surgical sutures.
authors.affiliation: Biomedical Polymers Technology Unit, Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: Y
authors.initials: Y
authors.lastname: Baimark
authors.forename: R
authors.initials: R
authors.lastname: Molloy
authors.forename: N
authors.initials: N
authors.lastname: Molloy
authors.forename: J
authors.initials: J
authors.lastname: Siripitayananon
authors.forename: W
authors.initials: W
authors.lastname: Punyodom
authors.forename: M
authors.initials: M
authors.lastname: Sriyai
mesh_terms: D020341:Absorbable Implants; D001672:Biocompatible Materials / Q000032:analysis / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D004548:Elasticity; D008422:Materials Testing; D011091:Polyesters / Q000032:analysis / Q000737:chemistry*; D012399:Rotation; D013314:Stress, Mechanical; D013537:Sutures; D013696:Temperature; D013718:Tensile Strength; D013784:Textiles; D044366:Transition Temperature
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; C062968:lactide-caprolactone copolymer