Isocyanate-terminated urethane prepolymer as bioadhesive base material: synthesis and characterization

The synthesis and characterization of NCO-terminated urethane prepolymer, a s a base material for the process of gluing in medicine have been studied. A polyol system consisting of a polyether/polyester mixture, together with toluene diisocyanate was employed to synthesis the desired urethane-based p repolymer. The molecular structure of this prepolymer was investigated by i nfrared spectroscopy (FTIR), gel permeation chromatography (GPC), gas chrom atography (GC) and thin layer chromatography (TLC). The obtained infrared s pectrum confirmed the presence of free NCO groups bonded to the prepolymer backbone. The spreading or wetting behavior df the synthesized prepolymer w as also studied by viscosity and surface tension measurement. The prepared prepolymer was found to behave as a bingham plastic from the rheological po int of view. The setting and curing rate of the prepolymer was studied at a mbient condition from the variation in NCO infrared peak intensity. It was found that the process of solidification of the liquid prepolymer occurs ra ther faster than its complete curing. Water and special catalysts were foun d to enhance the setting rate. The surface behavior and physico-mechanical properties of the cured thin films of the prepolymer were characterized usi ng contact angle measurements, dynamic-mechanical and tensile tests. The cy totoxicity of the him was evaluated by in vitro cell culture experiment. Re sults showed a compatible cell response with no signs of toxicity. (C) 2000 Elsevier Science Ltd. All rights reserved.