Percolation phenomena in the polymer composites with conducting polymer fillers

The electrical properties of polymer nanocomposites based on dielectric polymer matrices of different types and electrically conductive polymer fillers – polyortotoluidine, polyorthoanisidine and polyaniline have been studied. It is shown that the concentration dependence of the specific conductivity on the content of fillers has a percolation character with a low “percolation threshold”, which depends on the nature of the polymer matrix and polyaminoarene and is 1.7-10.0 vol.%. The calculated critical parameters of electroconductivity are characteristic of the formation of an infinite 3-dimensional cluster of conductivity and indicate a significant influence of the nature of the components and morphology of the material on the charge transfer processes in such systems.

Applications of Spectroscopic Techniques for Polymer Nanocomposite Characterization

During past decades, spectroscopic techniques find wide range of applications ranging from biological applications to the measurement of chemical composition and characterization of variety of substances i.e., polymers, nanocomposites etc. Nanocomposites are emerging and growing materials having wide variety of uses. To study the characteristic properties, characterize, and development of new materials using polymer nanocomposites, several molecular characterization techniques are available and are in use today. Principle objective of this review is to summarize the knowledge in current characterization techniques and to study the applications of fluorescence, solid-state nuclear magnetic resonance (NMR), infrared, besides Raman molecular characterization techniques for characterization of polymers, filler, and composites. Fluorescence technique did not provide detailed analysis of materials while solid-state NMR spectroscopy determine silanol hydroxyl groups at the silica exterior in addition to their interactions with polymer and polymer-filler interfacial interactions (via relaxation time). For characterization of various kinds of functional groups in polymer/ fillers, infrared spectroscopy employed. While Raman spectroscopy finds extensive applications for analysis of carbon-based materials. Novelty of this review is that till yet very few review papers have been published which briefly describe all these mentioned techniques along their applications in a very simple and an effective way.

Applications of Spectroscopic Techniques for Polymer Nanocomposite Characterization

During past decades, spectroscopic techniques find wide range of applications ranging from biological applications to the measurement of chemical composition and characterization of variety of substances i.e., polymers, nanocomposites etc. Nanocomposites are emerging and growing materials having wide variety of uses. To study the characteristic properties, characterize, and development of new materials using polymer nanocomposites, several molecular characterization techniques are available and are in use today. Principle objective of this review is to summarize the knowledge in current characterization techniques and to study the applications of fluorescence, solid-state nuclear magnetic resonance (NMR), infrared, besides Raman molecular characterization techniques for characterization of polymers, filler, and composites. Fluorescence technique did not provide detailed analysis of materials while solid-state NMR spectroscopy determine silanol hydroxyl groups at the silica exterior in addition to their interactions with polymer and polymer-filler interfacial interactions (via relaxation time). For characterization of various kinds of functional groups in polymer/ fillers, infrared spectroscopy employed. While Raman spectroscopy finds extensive applications for analysis of carbon-based materials. Novelty of this review is that till yet very few review papers have been published which briefly describe all these mentioned techniques along their applications in a very simple and an effective way.

Universality of mesoporous coal gasification slag for reinforcement and deodorization in four common polymers

Mesoporous adsorbents and polymer deodorants are difficult to implement on a large scale because of their complicated preparation methods. Herein, a mesoporous adsorbent (CGSA) with a specific surface area of 564 m2 g−1 and a pore volume of 0.807 cm3 g−1 was prepared from solid waste coal gasification slag (CGS) using a simple acid leaching process. The adsorption thermodynamics and adsorption kinetics results verified that the adsorption mechanism of propane on CGSA was mainly physisorption. Then the universality of CGSA in different polymers was investigated by introducing CGSA and its commercialized counterparts (CaCO3, and zeolite) into four common polymers. When the filler content was 30 wt%, the average reinforcement effect of CGSA on the tensile, flexural, and impact strengths of the four polymers was 46.68, 83.62, and 211.90% higher than that of CaCO3, respectively. Gas chromatography results also showed that CGSA significantly decreased total volatile organic compound (VOCs) emissions from the composites, and its optimal deodorization performance reached 69.58, 81.33, and 91.09% for different polymers, respectively, far exceeding that of zeolite. Therefore, this study showed that low-cost, high-performance, and multifunctional mesoporous polymer fillers with excellent universality can be manufactured from solid contaminants.

Polymer Adsorbents vs. Functionalized Oxides and Carbons: Particulate Morphology and Textural and SurfaceCharacteristics

Various methods for morphological, textural, and structural characterization of polymeric, carbon, and oxide adsorbents have been developed and well described. However, there are ways to improve the quantitative information extraction from experimental data for describing complex sorbents and polymer fillers. This could be based not only on probe adsorption and electron microscopies (TEM, SEM) but also on small-angle X-ray scattering (SAXS), cryoporometry, relaxometry, thermoporometry, quasi-elastic light scattering, Raman and infrared spectroscopies, and other methods. To effectively extract information on complex materials, it is important to use appropriate methods to treat the data with adequate physicomathematical models that accurately describe the dependences of these data on pressure, concentration, temperature, and other parameters, and effective computational programs. It is shown that maximum accurate characterization of complex materials is possible if several complemented methods are used in parallel, e.g., adsorption and SAXS with self-consistent regularization procedures (giving pore size (PSD), pore wall thickness (PWTD) or chord length (CLD), and particle size (PaSD) distribution functions, the specific surface area of open and closed pores, etc.), TEM/SEM images with quantitative treatments (giving the PaSD, PSD, and PWTD functions), as well as cryo- and thermoporometry, relaxometry, X-ray diffraction, infrared and Raman spectroscopies (giving information on the behavior of the materials under different conditions).

Physico-Chemical Properties of a Hybrid Biomaterial (Pva/Chitosan) Reinforced With Conductive Fillers

A novel hybrid material based on Polyvinyl alcohol-Chitosan (PVA-Cs) was made, reinforced with conductive polymer fillers such as polypyrrole (PPy), Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), carbon black (CB) and multi-wall carbon nanotubes (MW CNT). Our proposal is to use these fillers, which have not been studied in this context before, for obtaining composite materials, and to characterize them for the development of applications in microelectronics. FTIR analysis made evident the different func-tional groups present in the matrix and the fillers used. The use of quaternary mixtures (4 fillers) increased the contact angle, which increased the degree of hydrophobicity of the biocomposite. The Nyquist diagram of the analyzed samples showed a decrease in resistance and energy diffu-sion; the latter due to the transfer of electrons caused by the conductive polymers CB and the MWCNT. In the mechanical tension tests, Young's modulus values of 18.386 MPa were obtained, in contrast with the material matrix of PVA-Cs, which showed values of 11.628 MPa. Further-more, morphological analysis by SEM showed that the materials obtained were homogeneous, with no phase formation. The materials obtained showed higher electrical conductivity in the presence of the OH and NH2 groups, which could have possible applications in biopolymer elec-trodes.

Mechanochemical synthesis of carbon-stabilized Cu/C, Co/C and Ni/C nanocomposites with prolonged resistance to oxidation

Metal-carbon nanocomposites possess attractive physical-chemical properties compared to their macroscopic counterparts. They are important and unique nanosystems with applications including in the future development of nanomaterial enabled sensors, polymer fillers for electromagnetic radiation shields, and catalysts for various chemical reactions. However, synthesis of these nanocomposites typically employs toxic solvents and hazardous precursors, leading to environmental and health concerns. Together with the complexity of the synthetic processes involved, it is clear that a new synthesis route is required. Herein, Cu/C, Ni/C and Co/C nanocomposites were synthesized using a two-step method including mechanochemical treatment of polyethylene glycol and acetates of copper, nickel and cobalt, followed by pyrolysis of the mixtures in an argon flow at 700 °C. Morphological and structural analysis of the synthesized nanocomposites show their core-shell nature with average crystallite sizes of 50 (Cu/C), 18 (Co/C) and 20 nm (Ni/C) respectively. The carbon shell originates from disordered sp2 carbon (5.2–17.2 wt.%) with a low graphitization degree. The stability and prolonged resistance of composites to oxidation in air arise from the complete embedding of the metal core into the carbon shell together with the presence of surface oxide layer of metal nanoparticles. This approach demonstrates an environmentally friendly method of mechanochemistry for controllable synthesis of metal-carbon nanocomposites.

Enhanced optomechanical properties of mechanochemiluminescent poly(methyl acrylate) composites with granulated fluorescent conjugated microporous polymer fillers

With the combination of mechanochemiluminescence from 1,2-dioxetane coupled polymers and conjugated microporous polymer nanosheets, a new kind of filling-type mechanolumninescent polymer composite was developed.