Synthesis, characterization and melt spinning of a block copolymer of L-lactide and ε -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.

Electrospun Polyhydroxybutyrate and Poly(L-lactide-co-ε-caprolactone) Composites as Nanofibrous Scaffolds

“…A statistical copolymer of poly(L-lactide-co- ε -caprolactone), PLCL 67 : 33 (mole %), was synthesized by ring-opening bulk polymerization (ROP) at 120°C for 72 hours using SnOct 2 as the initiating system [27, 28]. Polyhydroxybutyrate (PHB) of natural origin and trypsin was purchased from Sigma Aldrich (Sydney, Australia).…”

Crystallization Study and Comparative in Vitro–in Vivo Hydrolysis of PLA Reinforcement Ligament

“…The other biomedical applications of PLA include the development of scaffolds [15], biocomposite material [16], sutures [17], prosthetics, etc. Moreover, low molecular weight PLA is used in tissue engineering [18,19]. …”

Lamellar stack formation and degradative behaviors of hydrolytically degraded poly(ε‐caprolactone) and poly(glycolide‐ε‐caprolactone) blended fibers

“…18, 19 This degradation is further exacerbated by autocatalytic mechanisms generated by the rapid pH drop occurring in the glycolide backbone interchain once water molecules surround the polymer backbone. Blends of PCL and PGA can decrease the brittleness of PGA alone, but to achieve large % elongation, we explore the blending PCL with segmented PGA‐PCL‐PGA triblocks (PGA y ‐(PCL m ‐PGA n ) x ‐PGA y ) that contains 25 mol % ε‐caprolactone and 75 mol % glycolide 20–22. In this blend, soft caprolactone/glycolide (PCL m ‐PGA n ) segments are inserted in between hard glycolide (PGA y ) segments to improve its mechanical properties.…”