Shape-memory polymer networks from oligo[(epsilon-hydroxycaproate)-co-glycolate]dimethacrylates and butyl acrylate with adjustable hydrolytic degradation rate

Biomacromolecules. 2007 Mar;8(3):1018-27. doi: 10.1021/bm0610370. Epub 2007 Feb 17.

Abstract

Degradable shape-memory polymer networks intended for biomedical applications were synthesized from oligo[(epsilon-hydroxycaproate)-co-glycolate]dimethacrylates with glycolate contents between 0 and 30 mol % using a photopolymerization process. In addition AB copolymer networks were prepared by adding 60 wt % n-butyl acrylate as comonomer. All synthesized polymer networks are semicrystalline at room temperature. A melting transition T(m) between 18 and 53 degrees C which can be used as switching transition for the shape-memory effect can be attributed to the crystalline poly(epsilon-hydroxycaproate) phase. At temperatures below T(m) the elastic properties are dominated by these physical cross-links. At temperatures higher than T(m) the E modulus of the amorphous polymer networks is lowered by up to 2 orders of magnitude, depending on the chemical cross-link density. Copolymer networks based on macrodimethacrylates with a M(n) of up to 13,500 g x mol(-1) and a maximum glycolate content of 21 mol % show quantitative strain recovery rates in stress-controlled cyclic thermomechanical experiments. Hydrolytic degradation experiments of polymer networks performed in phosphate buffer solution at 37 degrees C show that the degradation rate can be accelerated by increasing the glycolate content and decelerated by the incorporation of n-butyl acrylate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylates / chemistry*
  • Biocompatible Materials / chemistry
  • Calorimetry, Differential Scanning
  • Cross-Linking Reagents / chemistry
  • Cross-Linking Reagents / pharmacology
  • Gels
  • Hydrogen-Ion Concentration
  • Hydrolysis
  • Macromolecular Substances / chemistry
  • Methacrylates / chemistry*
  • Models, Statistical
  • Polyesters / chemistry*
  • Polymers / chemistry*
  • Temperature
  • Water / chemistry

Substances

  • Acrylates
  • Biocompatible Materials
  • Cross-Linking Reagents
  • Gels
  • Macromolecular Substances
  • Methacrylates
  • Polyesters
  • Polymers
  • poly((epsilon-hydroxycaproate)-co-glycolate)dimethacrylate
  • Water
  • n-butyl acrylate