The structure-properties relationships of sustainable materials derived from biomass-based monomers are investigated, focusing on hybrid styrene/terpene-based copolymers with blocky microstructures, such as β-myrcene- and β-ocimene-styrene copolymers. The samples show complex glass transition dynamics, as evidenced by the physical aging experienced by the amorphous phase in styrene-rich copolymers. The tendency of styrene- and terpene-rich sequences to give heterogeneous morphologies with correlation strength extending over 10-40 nm is outlined, through small-angle X-ray scattering analysis.
View Article and Find Full Text PDFThermofluorochromic materials exhibit tunable fluorescence emission on heating or cooling. They are highly desirable for applications ranging from temperature sensing to high-security anti-counterfeiting. Luminescent matrices based on liquid crystals are very promising, particularly those based on liquid crystals with intrinsic fluorescence.
View Article and Find Full Text PDFNanotechnology for biomedicine has recently attracted increasing interest from the scientific community. In particular, among the different nanodevices suitable for this application, multifunctionalizable hybrid nanoparticles are one of the most investigated research topics. Here we present a detailed physico-chemical characterization of hybrid magneto-plasmonic iron oxide-gold nanoparticles (NPs) with core-shell structure.
View Article and Find Full Text PDFThe deformation behavior of semicrystalline polymers associated with polymorphic transformations under tensile deformation is discussed in the case of syndiotactic polypropylene. We report a phase diagram of this polymer where the regions of stability of the different polymorphic forms are defined as a function of the degree of stereoregularity and deformation. The values of critical strain corresponding to the structural transformations depend on the stereoregularity that affects the relative stability of the involved polymorphic forms and the state of the entangled amorphous phase.
View Article and Find Full Text PDFHeterocycle-fused titanium indenyl silylamido dimethyl complexes produce very high molecular weight polypropylene having a prevailingly syndiotactic microstructure with syndiotactic pentad contents rrrr up to 40-55% (sam-PP). The samples are basically amorphous and may slowly develop a low level of crystallinity (16-20%) at room temperature. A structural characterization has shown that sam-PP samples crystallize in disordered modifications of the helical form I of syndiotactic polypropylene (s-PP).
View Article and Find Full Text PDFMelting enthalpies of several ethene-propene samples, obtained by different single-center catalytic systems and having widely different constitutions and compositions in the range of industrial interest, are compared. For the first time, a clear evidence of influence of the regio- and stereoregularity of propene insertion on crystallization behavior of ethene/propene copolymers is provided. This influence is in qualitative agreement with the results of simplified energy calculations relative to models of pseudo-hexagonal packing of ethene-propene copolymers.
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