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Bulk samples of pure polyvinyl chloride (PVC) and its composites with different content of methylene blue (MB) dye are prepared. The degree of crystallinity, dynamic elastic modulus E and shear modulus G (~1 MHz), photoluminescence (PL), temperature dependences of dielectric characteristics ε1, ε2, tgδ, electrical resistance R at different frequencies of alternating electric field are measured. As shown, the adding of a modifier (MB) with conjugated chromophores is accompanied by both the generation of linear conjugated systems (polyenes) in PVC and the destruction of monomer units. These processes are mechanisms for changing the mechanical, structural, optical, dielectric properties of PVC–MB composites caused by the peculiarities of the stack interaction between their conjugated components. [ABSTRACT FROM AUTHOR]

Composite samples based on microcrystalline cellulose matrix incorporated with micro/nanoparticles of La0.7Sm0.3VO4 complex oxide were made by cool pressing procedure. Morphology, crystallinity and characteristic luminescence and dielectric properties of the composites were studied. Their morphology can be described as "ceramics-like" type, as it consists of cellulose plates and embedded oxide particles. Luminescence spectra of the composites covers the range of the whole visible light, 350-750 nm, and comprises both wide band and narrow lines, related with host and oxide luminescence, respectively. Temperature dependences of the dielectric permittivity of composites showed the impact of the oxide particles on the characteristics of the microcrystalline cellulose. An assumption was made that this influence can be affected via water molecules, hydroxyl groups or molecules of the ambient gases. Studied composites can be perspective luminescent materials for transformation of ultraviolet and violet radiation into green-red light. [ABSTRACT FROM AUTHOR]