IMAGING OF SEMICRYSTALLINE POLYMERS AND POLYMER BLENDS BY FT-IR MICROSPECTROSCOPY

It has been demonstrated that Fourier transform infrared (FT-IR) micro spectroscopy can be used to study different types of spherulites of po ly(vinylidene fluoride) formed by different crystal modifications, Bec ause of selective IR bands of the alpha and the gamma modification, re spectively, it is possible to map the crystalline morphology by FT-IR microspectroscopy. Thus the different types of spherulites can be assi gned unambiguously to different crystal modifications. It is also poss ible to map the morphology of phase-separated blends of isotactic poly propylene and syndiotactic polypropylene. There are selective IR bands in the crystalline state as well as in the melt, This characteristic allows for observation of the phase morphology of blends containing is otactic and syndiotactic polypropylene directly in the melt even thoug h the blends appear completely transparent in the light microscope. Th is capability demonstrates the advantage of FT-IR microspectroscopy co mpared to light microscopy, which is restricted to samples with differ ences in the refractive index, which is not given for blends of isotac tic and syndiotactic polypropylene above the melting point.