Polymer Fillers and Stiffening Agents

2020 ◽  
Author(s):  
Chris Defonseka
Keyword(s):  
2012 ◽  
Vol 1487 ◽  
Author(s):  
R. Cué ◽  
G. Del Bosque ◽  
A. Sanchez

ABSTRACTTo fully accomplish all promises and hopes on clinical applications of carbon nanotubes, it is crucial to understand their interactions with physiological environment. One of these applications is polymer fillers, and it is important to review the toxicology of carbon nanotubes themselves because some polymer matrices may be biodegradable. Therefore, the interactions with organic molecules such as water, electrolytes, and proteins are reviewed and results of multiple studies on cellular interaction, cytotoxicity, immune response, biodistribution, and biopersistence are further presented. Finally, a section describing the interaction of polymer matrices with carbon nanotube reinforcements and the physiological environment is presented.


2009 ◽  
Vol 3 (2) ◽  
Author(s):  
B. M. Burgess ◽  
G. E. Gierke ◽  
M. C. Frost

Biomedical devices that contact blood and tissue universally inspire a host response that often compromises the function of the device (i.e., intravascular sensors become coated with thrombi, artificial vascular grafts become coated with thrombi, artificial vascular grafts become occluded with thrombus formation and neointimal hyperplasia). Nitric oxide (NO) has been shown to be a potent inhibitor of platelet adhesion and activation and has been implicated in mediating the inflammatory response and promoting would healing. We are currently developing NO-releasing compounds based on S-nitrosothiols derived from substituted aromatic compounds that utilize light as an external on/off trigger capable of releasing precisely controlled surface fluxes of NO. The level of NO generated is dependent on the wavelength and intensity of light shown on the compounds. Data will be presented that show the synthesis and NO-release properties of three novel compounds, S-nitroso-2-methoxybenzene, S-nitroso-3-methoxybenzene and S-nitroso-2-chlorobenzene. Ultimately, these compounds will be tethered to the surface of polymer fillers that will then be blended into hydrophobic polymers and used as coatings on biomedical devices. A model system that will be used to demonstrate the utility of this approach will be a multi-element fiber optic sensors that will contain sensing elements capable of measuring blood gases and NO-releasing fibers that locally generate enough NO to inhibit clot formation on the sensor surface, thus allowing the sensor to function reliably in vivo.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mariia Galaburda ◽  
Evgeniya Kovalska ◽  
Benjamin T. Hogan ◽  
Anna Baldycheva ◽  
Andrii Nikolenko ◽  
...  

AbstractMetal-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.


2013 ◽  
Vol 6 (1) ◽  
pp. 585-592 ◽  
Author(s):  
Brian M. Mosby ◽  
Agustín Díaz ◽  
Vladimir Bakhmutov ◽  
Abraham Clearfield

ACS Nano ◽  
2016 ◽  
Vol 10 (8) ◽  
pp. 8012-8018 ◽  
Author(s):  
Alejandro López-Moreno ◽  
Belén Nieto-Ortega ◽  
Maria Moffa ◽  
Alberto de Juan ◽  
M. Mar Bernal ◽  
...  

2014 ◽  
Vol 50 (70) ◽  
pp. 10137-10139 ◽  
Author(s):  
Fabio Ziarelli ◽  
Mario Casciola ◽  
Monica Pica ◽  
Anna Donnadio ◽  
Fabien Aussenac ◽  
...  

1981 ◽  
Vol 54 (2) ◽  
pp. 197-210 ◽  
Author(s):  
N. D. Ghatge ◽  
S. P. Vernekar ◽  
S. V. Lonikar

Abstract Sealants based on polysulfide liquid polymers are widely used in a number of applications. These sealants are solvent and chemical resistant, having good flexibility and adherence to many substrates such as steel, aluminum, glass, concrete, wood, etc. These are used to line fuel tanks of aircraft and to seal fuel tanks and rivetted joints in aircraft. These sealants, being water resistant, are widely used in ship building to seal decks and planking. Since these sealants have good weather resistance and can withstand stress and strain, they are widely used in the building industry. They are found to be very satisfactory in modern curtain walls and in sealing windshields of motorcars. Their use in airfield and runway constructions is well known. These sealants generally have a two-pot system consisting of (i) a base caulk containing a liquid polysulfide polymer, fillers, plasticizers, adhesive promotors, thickening agents, accelerators or retarders and (ii) a curing agent. Sometimes accelerators and retarders are used as a third pot system to regulate the pot life of caulking compounds.


Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1249
Author(s):  
Volodymyr M. Gun’ko

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).


2021 ◽  
Vol 22 (4) ◽  
pp. 811-816
Author(s):  
G.V. Martyniuk ◽  
O.I. Aksimentyeva

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.


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