Wyniki wyszukiwania - BazTech

1

Kompozyty żywicy epoksydowej z napełniaczami węglowymi : struktura i właściwości

Ciecierska E., Boczkowska A., Chabera P., Wiśniewski T., Kubiś M.

Przemysł Chemiczny

|

2015

|

T. 94, nr 11

2033-2037

PL

Wytworzono kompozyty o wysokim przewodnictwie elektrycznym oraz cieplnym i polepszonych właściwościach mechanicznych. Do badań wybrano 2 rodzaje napełniaczy węglowych: nanorurki węglowe oraz sadzę. Wykonano kompozyty o różnej zawartości napełniaczy. Przeprowadzono obserwacje mikroskopowe w celu oceny wpływu napełniaczy węglowych na strukturę materiału i określenia stopnia dyspersji. Wytworzone kompozyty poddano testom na udarność i wytrzymałość na zginanie. Zbadano także przewodnictwo elektryczne i dyfuzyjność cieplną oraz stabilność termiczną kompozytów. Wykazano, że dodatek nanorurek węglowych skuteczniej zwiększa przewodnictwo elektryczne i dyfuzyjność cieplną polimeru w porównaniu z sadzą. Lepsze właściwości mechaniczne uzyskano również dla polimerów z dodatkiem nanorurek węglowych.

EN

Epoxy resin matrix was reinforced with C nanotubes or C black to improve properties of the composites. The addn. of the C nanotubes resulted in an increase in the elec. cond., mech. strength and thermal diffusivity of the composites to a higher extent than the addn. of C black.

2

The effect of the surface modification of carbon nanotubes on their dispersion in the epoxy matrix

Wladyka-Przybylak M., Wesolek D., Gieparda W., Boczkowska A., Ciecierska E.

Polish Journal of Chemical Technology

|

2011

|

Vol. 13, nr 2

62-69

EN

Functionalization of multi-walled carbon nanotubes (MWCNTs) has an effect on the dispersion of MWCNT in the epoxy matrix. Samples based on two kinds of epoxy resin and different weight percentage of MWCNTs (functionalized and non-functionalized) were prepared. Epoxy/carbon nanotubes composites were prepared by different mixing methods (ultrasounds and a combination of ultrasounds and mechanical mixing). CNTs modified with different functional groups were investigated. Surfactants were used to lower the surface tension of the liquid, which enabled easier spreading and reducing the interfacial tension. Solvents were also used to reduce the liquid viscosity. Some of them facilitate homogeneous dispersion of nanotubes in the resin. The properties of epoxy/nanotubes composites strongly depend on a uniform distribution of carbon nanotubes in the epoxy matrix. The type of epoxy resin, solvent, surfactant and mixing method for homogeneous dispersion of CNTs in the epoxy matrix was evaluated. The effect of CNTs functionalization type on their dispersion in the epoxy resins was evaluated on the basis of viscosity and microstructure studies.

3

Urea-urethane nanocomposites obtained from modified methylalumoxane oligomers

Boczkowska A., Marczewski M., Ciecierska E., Sienkiewicz B., Pietrzykowski A.

Materials Science Poland

|

2008

|

Vol. 26, No. 2

301--308

EN

Urea-urethane elastomers were synthesized in a polyaddition reaction of ethylene oligoadipate (OAE) of an average molecular weight 2000 u with bis(4-isocyanatephenyl)methane (MDI). Dicyandiamide was used as a chain extender. In order to obtain hybrid nanocomposites, OAE was modified by the reaction with methylalumoxanes (MAO) prior to use. The excess of active methyl groups of MAO was deactivated by reactions with alcohols or alkylphosphates. This method allowed one to introduce nanosized aluminum-oxide based moieties into the polyurethane. The amount of nanoparticles was equal to 3 wt. %. The aim of the study was a homogeneous molecular dispersion of aluminum-oxide units in order to obtain urea-urethane nanocomposites with a higher fire resistance and improved mechanical properties. Microstructure of the nanocomposites was studied with the high resolution scanning electron microscopy (HRSEM). Mechanical properties were examined by standard testing procedures. Flammability tests were also performed using a cone calorimeter under heat flux equal to 50 kW/m2. The results of the microstructure studies show even distribution of the nano-sized aluminum-oxide units in the polyurethane bulk. We observed an increase of such properties as Young's modulus and hardness, accompanied by a significant decrease in the heat release rate.