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Full-Text Articles in Physical Sciences and Mathematics
Electrical And Mechanical Properties Of Polymer Nanocomposites, Nuwansiri N.K. Getangama
Electrical And Mechanical Properties Of Polymer Nanocomposites, Nuwansiri N.K. Getangama
Electronic Thesis and Dissertation Repository
This thesis consists of three projects concerning the electrical and mechanical properties of polymer nanocomposites. We study the effect of nanoscale filler particles on the polymer dynamics at different length and time scales. In the first study, poly(ethylene oxide) (PEO)-multiwalled carbon nanotubes (MWCNT) nanocomposites with a MWCNT concentration ranging from 0 to 5 wt\% were prepared by both melt-mixing and twin-screw extrusion. Their electrical properties were studied over a wide range of frequency and temperature using a dielectric spectrometer. A percolation transition is observed at which the electrical conductivity of the nanocomposites increases by several orders of magnitude. The percolation …
Dielectric Spectroscopy Of Polyvinyl Alcohol Hydrogels And Nanocomposites, Nuwansiri N.K. Getangama
Dielectric Spectroscopy Of Polyvinyl Alcohol Hydrogels And Nanocomposites, Nuwansiri N.K. Getangama
Electronic Thesis and Dissertation Repository
Gels based on polyvinyl alcohol (PVA) can be formed by repeated freezing and thawing of a solution of the polymer. PVA cryogels have applications as biomaterials, including artificial tissue and drug delivery systems. The mechanical and electrical properties of polymeric materials can be changed significantly by adding a small amount of nanometer-sized particles. In this work, the dielectric properties of PVA solutions and gels were studied in the frequency range from 10 micro Hz to 1 MHz as a function of temperature, using a dielectric spectrometer. Comparison of the dielectric constant of a PVA solution to that of water indicates …
Rheology Of Solutions Of Polyisophrene And Polyisoprene-Carbon Nanotube Composites, Ruiping Ge
Rheology Of Solutions Of Polyisophrene And Polyisoprene-Carbon Nanotube Composites, Ruiping Ge
Electronic Thesis and Dissertation Repository
The addition of a small amount of carbon nanotubes to a polymer matrix can result in large changes in its mechanical properties. In this work, we study the rheological behavior of solutions of polyisoprene (PI) in chloroform and suspensions of multi-walled carbon nanotubes (MWCNT) and single-walled carbon nanotubes (SWCNT) in these PI solutions using shear rheometry.
We perform rheological measurements to study the viscoelastic properties of solutions of trans-PI in chloroform for polymer concentrations ranging from 1.0 wt% to 10.0 wt%. Oscillatory strain sweep tests show a concentration-and-frequency independent critical strain of that defines the limit of the linear viscoelastic …