Abstract
Solid state NMR was successfully used to determine the proton spin-lattice relaxation time in the rotating frame (T1ρH) for systems based on polypropylene (PP) and PP with titanium dioxide (TiO2) organically modified or unmodified incorporated, in order to understand the molecular behavior of these systems. These techniques were employed in the samples organically modified and unmodified TiO2 to investigate the effect of organic modification on the dispersion and distribution of the particles in the PP matrix. The results were analyzed in terms of the effect of the particles organic modified or not according to the intermolecular interaction in the composites. According to the T1ρH values, all composites showed at least two domains: the short values were related to the rigid part, which included the crystalline and amorphous phase constricted in it, while the longer times were attributed to the amorphous region, which had higher molecular mobility compared to the rigid region of the materials. The increase in the relaxation time parameter in the composites compared to the pure PP was associated to the strong interaction between titanium dioxide particles and the polymer chains. This effect was more pronounced for the systems containing organically modified TiO2. According to the results, it could be inferred that intermolecular interaction occurred in the CH2 and CH groups, being more intense with CH2 groups. Finally, the solid state NMR techniques were able to evaluate the molecular dynamics of those systems.
Highlights
Solid-state nuclear magnetic resonance is a non-destructive spectroscopy and it comprises many techniques and permits us to analyze several nucleuses that contain different information on materials, especially polymer and their derivative materials [1]-[5]
The hydrogen MAS is an important technique to help the evaluation of chains molecular dynamics and together with the carbon-13 Nuclear Magnetic Resonance Spectroscopy (NMR) responses allow to understand the behavior of polymer systems [19] [20]
Analyzing the materials prepared with PP and TiO2 modified or not, the thermal parameters of the polymer matrix did not change, which is an indication that the particles did not influence processing stability and no degradation was detected
Summary
Solid-state nuclear magnetic resonance is a non-destructive spectroscopy and it comprises many techniques and permits us to analyze several nucleuses that contain different information on materials, especially polymer and their derivative materials [1]-[5]. Carbon-13 is an important nucleus that gives many responses on polymer chemical structure, arrangements, configurational and is specific to evaluate the molecular dynamics of polymers and materials based on it [6]-[11]. According to this statement, in this work, we have chosen to use the solid-state carbon-13 NMR spectroscopy as a tool to evaluate the systems formed by PP and titanium oxide modified or not, in order to obtain response on the molecular interaction between polymer and particles and the way that the particles are dispersed and distributed. The spin-lattice relaxation in the rotating frame can be determined through the decay of the resolved carbons during the variable contact time experiment under spin-lock conditions that generate a rotating magnetic field near the resonant frequency perpendicular to the static magnetic field [12]-[18].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
