A comparative study on structure-property elucidation of P3/4HB and PEG-based block polyurethanes

A series of alternating block polyurethanes (abbreviated as PU3/4HB-alt-PEG) and random block polyurethanes (abbreviated as PU3/4HB-ran-PEG) based on biodegradable polyester poly(3-hydroxybutyrate-co-4-hydroxybutrate) (P3/4HB-diol) and poly(ethylene glycol) (PEG) with similar chemical compositions were synthesized using 1, 6-hexamethylene diisocyanate (HDI) as coupling agent. The chemical structure, molecular weight and distribution were characterized by FTIR, 1H NMR, and GPC. The thermal differences were investigated by DSC. The hydrophilicity was studied by static contact angle and the results revealed that PU3/4HB-alt-PEG is more hydrophilic with a higher surface energy than PU3/4HB-ran-PEG. With SEM observation, PU3/4HB-alt-PEG exhibited a regular characterized microstructure with flower-type patterns on the surface, while PU3/4HB-ran-PEG displayed no regular pattern. A platelet adhesion study illustrated that PU3/4HB-alt-PEG possesses better hemocompatibility due to its more hydrophilic surface and evident surface microstructure. The cell culture assay demonstrated that fibroblasts and rat glial cells were more favorable for attachment on PU3/4HB-alt-PEG films. By comparison, alternating block polyurethanes provides a way to control the exact structure of the biomaterials and tailor better properties to biomedical requirements. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A: 23192329, 2012.