Real uniform dispersion of barium titanate, BaTiO 3 , submicrometric particles within Poly(vinylidene fluoride), PVDF, was achieved to understand induced structure, morphology, and crystallization process of the polymer. Composites with uniform dispersions of BaTiO 3 particles within PVDF were accomplished for the first time, blending the polymer with particles by high energy ball milling, HEBM. Different compositions in PVDF/BaTiO 3 composite were considered (0, 1, 5, and 10 weight percent of particles). Morphology and structure were studied by scanning electron microscopy, SEM, and X-ray diffraction, XRD, respectively. From dynamic experiments by differential scanning calorimetry, DSC, thermal transitions were determined and melting and crystallization processes were studied. To understand the main mechanism by which specific morphologies can be obtained a deep kinetic analysis of the PVDF crystallization process was carried out. Cooling rate and BaTiO 3 content did not provide important variations in the PVDF crystalline structure and morphology; however, the presence of BaTiO 3 particles seemed to favor an athermal nucleation, leading to higher fraction of crystals in shorter times.

Summary: In this work infrared spectroscopy in the near infrared (NIR) range is used to study the dynamics of polymethylmethacrylate (PMMA) as a pure polymer and when it is modified with silica nanoparticles. Different ways of analyzing FT-NIR spectra were explored taking the temperature as the variable of the systems: i) bands shifts in terms of the first moment of the wavenumber; ii) bands shifts in terms of an absorbance ratio method and iii) absorbance variations in terms of the integrated absorbance. The spectroscopic analysis allowed to study thermal transitions in PMMA and PMMA based nanocomposites. In particular the method based on the use of an absorbance ratio is the most sensible to analyze the thermal transitions. All bands considered could be used to detect thermal transitions reflecting how the vibrations of the groups CH 2 ; CH 3 and C¼O are affected by changes in the free volume of the PMMA. It seems that the PMMA dynamics is more driven by the lateral groups than the backbone of the polymer. The presence of silica nanoparticles, at least when 1% by weight is used, restrains the PMMA motion increasing the relaxation temperatures that can be associated with the glass transitions.