Supercritical CO2 (scCO2) foaming of poly(l-lactic acid)
composite films with liquid polyhedral oligomeric
silsesquioxanes (PlLA-POSS) was carried out to obtain polymer
matrices for drug delivery applications. Highly crystalline (>45%)
PlLA generally requires high supercritical processing (saturation)
temperatures close to its melting temperature (∼450 K) and
pressures about or over 20 MPa for foaming with scCO2.
To decrease the saturation temperature and obtain ductile PlLA films with uniform and homogeneous porosity, we used two different,
novel CO2-philic organic–inorganic hybrid liquid
POSS as cell nucleators. The solvent-casting of the polymer with these
additives resulted in porous thin films. ScCO2 processing
at 313 K and 21 MPa increased the pore density and enhanced the mechanical
and thermal properties such as elastic modulus and T
g of the highly crystalline PlLA porous films.
ScCO2 processing led to the extraction of the cell nucleators,
allowing the recovery of these additives from the porous films. Drug
release studies with a model antibiotic (Ceftriaxone Sodium) showed
that the porous films exhibit burst release characteristics, which
is suitable for local antibiotic applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.