Amphiphilic elastomeric polyurethane networks: thermal and swelling behavior

C. SANZ PITA; P.C. CARACCIOLO; F. BUFFA; G.A. ABRAHAM

La Habana

Congreso; V Congreso Internacional de Biomateriales (BIOMAT 2010); 2010

Universidad de La Habana y Red Iberoamericana CYTED

Polyurethanes continue playing a key role in the development of many different biomedical devices due to their exceptional biocompatibility, mechanical properties and versatility. Although linear segmented polyurethanes are the more extensively studied, investigation on crosslinked polyurethanes is still limited. In this work, a series of crosslinked polyurethanes were synthesized by reaction of poly(ethylene glycol) (PEG400), hexamethylene diisocianate (HDI) and poly(-caprolactone) triols with molecular weights of 1280 and 3130 Da. PEG was used as hydrophilic macrodiol, PCL triol as hydrophobic macrocrosslinker, and dibutyltin dilaurate as catalyst. The hydrophilic/hydrophobic ratio was varied by selecting appropriate amounts of monomers. A predetermined amount of PCL triol (PCL900, PCL1060 or PCL3130) was dissolved in N,N?-dimethylacetamide in a glass tube. Then, PEG and catalyst were added and mixed by vortexing. After the addition of HDI, the reactive mixture was vigorously mixed by vortexing, and then degassed under reduced pressure. Before curing, films were prepared by casting from the degassed colourless mixture in a Teflon dish, and allowed to cure at 60ºC for 24 h. Thermal properties of the monomers and the resulting elastomeric films were determined by differential scanning calorimetry (DSC). Swelling behavior was investigated in phosphate-buffered solution at 37ºC. The effect of the composition, in terms of content of hydrophilic monomer and crosskinker chain length, on the measured properties was analysed. These materials hold promise as controlled implantable drug delivery devices and antimicrobial coatings. Studies concerning the release of model drugs are in progress.