Structure and Mechanical Properties of Poly (D,L-lactic Acid)Poly(e-caprolatone)Blends
M E. Broz, David L. VanderHart, N Washburn
A series of blends of the miscible, biodegradable polymers poly(D,L-lactic acid) and poly(e-caprolactone) were prepared varying mass fraction across the range of compositions. Tensile testing was performed at room temperature using an extensometer and the elastic modulus was calculated for each blend. The blends were also tested to failure, and the strain-at-failure and ultimate tensile strength recorded. While the blend has been shown to be miscible in the melt state, the mechanical properties were insensitive to the annealing conditions. Scanning electron microscopy was used to characterize the blend microstructure and poor adhesion was observed at the interface between blend components.Differential scanning calorimetry was performed and the glass transition temperature and melting temperature were found to be essentially unchanged from those of the pure polymers, suggesting little mixing has occurred between the two polymers. Nuclear magnetic resonance data indicate the two components are phase separated, which we tentatively attribute to poly(e-caprolactone) crystallization. A percolation model is used to explain the observed mechanical data and the results are consistent with the predictions of the Kerner-Uemura-Takayangi model.
biodegradable polymers, mechanical testing, polymer blends, solid state nuclear magnetic resonance
, VanderHart, D.
and Washburn, N.
Structure and Mechanical Properties of Poly (D,L-lactic Acid)Poly(e-caprolatone)Blends, Biomaterials
(Accessed December 11, 2023)