SURFACE AND BULK STRUCTURE OF SEGMENTED POLY(ETHER URETHANES) WITH PERFLURO CHAIN EXTENDERS .5. INCORPORATION OF POLY(DIMETHYLSILOXANE) ANDPOLYISOBUTYLENE MACROGLYCOLS

Nonpolar hydrophobic soft segments were synthetically incorporated int o polyurethanes based on 4,4'-methylenebis(phenyl isocyanate) (MDI)/he xafluoro-1,5-pentanediol (FP)/poly(tetramethylene glycol) (PTMO). The soft segments incorporated were dihydroxy-terminated poly(dimethylsilo xane) (PDMS) and polyisobutylene (PIB). All soft segments have similar molecular weights (M(n) almost-equal-to approximately 2000). All poly mers prepared also have similar levels of hard segment (approximately 55 wt %), and they are soluble in common organic solvents. The solvent -cast polymers were studied by Fourier transform infrared (FTIR) spect roscopy, differential scanning calorimetry, electron spectroscopy for chemical analysis (ESCA), and static secondary-ion mass spectrometry ( SSIMS). The FTIR analysis showed that the absorption band at 3295 cm-1 is important for the interpretation of soft-segment mixing behavior i n segmented poly(ether urethanes). The surface analysis data revealed that the incorporation of 20 wt % or less of PIB or PDMS in the soft s egment may be sufficient to completely cover the polymer surface with each corresponding soft segment. The PDMS polyurethanes exhibited a pr onounced casting solvent dependence on the surface and bulk structure, while the PIB polyurethanes showed less dependence on casting solvent .