Preparation And Properties Of Functional Polyurethanes

In this thesis, we have prepared two types of functional graft polyurethane materials viaa combination of radical polymerization and condensation reaction. Our aim is to developfunctional polyurethane materials with high performance. The main results are as follows:1. Firstly, poly(2-(dimethylamino)ethyl methacrylate) oligomer (PDEM(OH)2) wassynthesized by radical polymerization using3-Mercapto-1,2-propanediol (TPG) as chaintransfer reagent to introduce a diol group at one end. Then the oligomer was polyadded withdiisocyanate to yield an amphiphilic polyurethane-g-poly(2-(dimethylamino)ethylmethacrylate)(PU-g-PDEM) copolymer, which can self-emulsify in water and formnanoparticles. Fourier transform infrared spectroscopy (FTIR), proton nuclear magneticresonance spectroscopy (1H-NMR) show that the PDEM side chains are incorporated into thePU. The effects of pH and temperature on particle stability have been examined by particleand zeta potential analyzer. It shows that the nanoparticles are stable in acidic medium (pH <7) even at70C. The nanoparticles were employed as the sole emulsifier for emulsionpolymerization of styrene (St) or methyl methacrylate (MMA). Our studies demonstrate thePU based nanoparticles can effectively stabilize St or MMA droplets and form PU/PS orPU/MMA composite emulsions in situ.2. We have also prepared polyurethane-g-poly(ethylene glycol)(PU-g-PEG) copolymers.FTIR and1H-NMR show that the PEG side chains are incorporated into the PU. Thermalanalysis indicates that the thermal stability of the graft copolymers are improved with theincreasing PEG content. By use of quartz crystal microbalance with dissipation (QCM-D), theabsorption of fibrinogen, human serum albumin and lysozyme on such a PU-g-PEG surfacewere investigated in real time. It shows that the incorporation of PEG into PU can effectivelyresist nonspecific protein adsorption when the content of PEG side chains is high enough. Wehave also studied the enzymatic degradation of PU-g-PEG copolymers in stiu. It showsPU-g-PEG can degrade obviously compared with the ungrafted PU.