Amphiphilic elastomeric polyurethane networks: thermal and swelling behavior

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

La Habana, Cuba

Congreso; V Congreso Internacional de Biomateriales BIOMAT; 2010

Cátedra UNESCO de Biomateriales

<!-- /* Font Definitions */ @font-face {font-family:Batang; panose-1:2 3 6 0 0 1 1 1 1 1; mso-font-alt:¢®E¡ËcE¡Ë¢çEcE¡Ë¢çE¢®EcEcE¡Ë¢çE; mso-font-charset:129; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1342176593 1775729915 48 0 524447 0;} @font-face {font-family:"@Batang"; panose-1:2 3 6 0 0 1 1 1 1 1; mso-font-charset:129; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1342176593 1775729915 48 0 524447 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:Batang;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> 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(e-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. The reaction was carried out in dimethylacetamide solution following a two-step procedure. First, a polyester triol solution was mixed with a predetermined excess of diisocyanate at 90ºC for 15 min. Then, a PEG solution was added and mixed by vortexing. Thin polyurethane films were prepared by casting the reaction mixture in a Petri dish, and allowed to cure in situ at 60ºC for 24 h. The solvent was removed by evaporation during curing stage and then exhaustively dried under vacuum. 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.