Synthesis, characterization and melt spinning of a block copolymer of L-lactide and epsilon-caprolactone for potential use as an absorbable monofilament surgical suture.
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.
Baimark
Y
Y
Biomedical Polymers Technology Unit, Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
Molloy
R
R
Molloy
N
N
Siripitayananon
J
J
Punyodom
W
W
Sriyai
M
M
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
D001672:Biocompatible Materials; D011091:Polyesters; C062968:lactide-caprolactone copolymer