Preparation and characterization of porous poly(urethane-urea) microparticles from poly(vinyl alcohol) and isophorone diisocyanate

The porous poly(urethane-urea) (PUU) microparticles are synthesized from poly(vinyl alcohol) (PVA) and isophorone diisocyanate (IPDI) in the dimethyl sulfoxide/water (99/1 vol%) solution by a one-step method. Influences of the initial molar ratio of PVA and IPDI, the reaction time and temperature on the yield and the structure of PUU are studied. The highest yield of PUU microparticles is 70.1%. The PUU are thoroughly characterized by the chemical analytical methods, infrared spectrometry, thermal analysis, surface area and pore volume analysis. The largest surface area is 122 m(2) . g(-1) and the total pore volume is 0.62 cm(3) . g(-1). Mainly the mesopore structure of PUU microparticles with the presence of macropores is estimated. The size and morphology of the PUU microparticles are evaluated by the scanning electron microscopy. The size distribution of PUU microparticles, which are synthesized under different conditions, is in the range of 2-10 mu m. Thermal decomposition of the PUU occurs in two stages according to TGA results.