| This thesis reports on the preparation and property determination of solvent-cast polyurethane films derived from AlcellRTM lignin. The films were made using a three component system, AlcellRTM lignin, 4,4'-diphenylmethane diisocyanate (MIDI) and PEG or plasticizers. An important goal was to incorporate as much lignin as possible. Two methods of synthesis, namely, using a polymerization catalyst versus a non-catalyst route, were investigated to produce films with measurable properties. A main focus was on PU films made from the catalyst route, using dibutyltin dilaureate as the catalyst of choice. The effects of varying the isocyanate to hydroxyl (NCO/OH) molar ratio and lignin content on crosslink density, mechanical properties and thermal properties as well as photo- and bio-degradation behavior of the films were studied.;With the assistant of the catalyst, PU films with a wide range of lignin content and NCO/OH molar ratio, 0∼50 wt% and 0.8∼3, respectively, could be prepared. (Abstract shortened by UMI.). |
