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LCST Phase Separation in Biodegradable Polymer Blends: Poly(D,L-lactide) and Poly(ε -caprolactone)



J C. Meredith, Eric J. Amis


A lower critical solution temperature (LCST) phase transition is reported for blends of the biodegradable polymers poly(D,L-lactide) (PDLA) and poly(ε-caprolactone) (PCL). From light scattering measurements the cloud point curve is determined to have a critical temperature of 86 C and a critical concentration of mass fraction 36% PCL. Optical microscopy of phase-separated films indicates a spinodal morphology at the critical concentration, and droplet phases at off-critical concentrations. After quenching phase separated blends below the melting temperature of PCL (60 C), the crystallization of PCL is used to positively identify PCL-rich and PDLA-rich phases. When crystallization of PCL follows LCST phase separation, the size, shape, and distribution of crystalline regions can be adjusted by the degree of PCL/PDLA phase separation. Thus, the LCST phase separation offers a novel method to control microphase structure in biodegradable materials. Applications to control of mechanical and physical properties in tissue engineering scaffolds are discussed in light of the results.
Macromolecular Chemistry and Physics
No. 6


biodegradable polymer, caprolactone, lactide, LCST, tissue engineering


Meredith, J. and Amis, E. (2000), LCST Phase Separation in Biodegradable Polymer Blends: Poly(D,L-lactide) and Poly(ε -caprolactone), Macromolecular Chemistry and Physics, [online], (Accessed May 20, 2024)


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Created December 31, 1999, Updated October 12, 2021