Adda 2

The molecular weight distribution and the average molecular weights were determined by size exclusion chromatography (SEC) using a LKB-2249 instrument at 25 °C. A series of four μ-Styragel columns, ranging in pore size 10 5 , 10 4 , 10 3 , 100 Å, was used with chloroform as an eluent. The sample concentration was 4-5 mg mL -1 and the flow rate was 0.5 mL min -1 . The polymer was detected by the carbonylic absorption of the ester group (5.75 μm), using an infrared detector (Miram 1A Infrared Analyzer) and the calibration was done with poly(methyl methacrylate) standard supplied by Polymer Laboratories and Polysciences.
The fractured sections of the scaffolds were obtained in liquid nitrogen using a razor blade, immediately afterward they were sputter with gold and their morphology was examined using scanning electron microscopy (SEM; Phillips 505, The Netherlands), with an accelerating voltage of 20 kV. The images were analyzed using Soft Imaging System ADDAII. The scaffolds surface was also examined by SEM.
Glass transition temperatures (T g ) were measured using a differential scanning calorimeter (Shimadzu-TA60). Samples (≈5 mg) were weighed and scanned at 10 °C min -1 from -30 to 150 °C under dry nitrogen (30 mL min -1 ). Three consecutive scans were performed for each sample: heating/cooling/heating.

Freeze-dried microspheres were prepared for SEM observation by sputtering the surface with gold using Balzers SCD 030 metalizer and obtaining layer thickness between 15 and 20 nm. Surface and morphology of microspheres were observed using Philips SEM 505 model (Rochester, USA), and processed by an image digitalizer program (Soft Imaging System ADDA II (SIS)).