Authors

Kai Yang

Type

Text

Type

Dissertation

Advisor

Rafailovich, Miriam H | Butcher, Thomas | Desikan, Anantha. | Gersappe, Dilip

Date

2015-08-01

Keywords

Plastics

Department

Department of Materials Science and Engineering.

Language

en_US

Source

This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.

Identifier

http://hdl.handle.net/11401/76364

Publisher

The Graduate School, Stony Brook University: Stony Brook, NY.

Format

application/pdf

Abstract

We have successfully fabricated the PP/GNPs nanocomposites that are thermally conductive, processable, and flame resistant. Thermal conductivity measurements indicated that the thermal coefficient scaled linearly with GNP loading, where a value of 2.0W/m*k was achieved at a loading of 40%. Tensile measurement indicated that the modulus increased, linearly with GNPs loading, while the IZOD impact and toughness after an initial decrease, remained constant for loading up to 50%. The torque required for extrusion increased only by 25% over this range indicating that the compound remained processable despite the high loading content. SAXS showed a large decrease in the amount of lamellar folding relative to the neat PP sample, while WAXS and DSC measurements, indicated a slight increase in the degree of crystallinity . These results are consistent with strong adsorption of the PP chains to the GNP, which, while maintaining crystallinity, disrupts the lamellar structure. Cone calorimetry showed that nanocomposites with 10% loading or higher exhibited a dramatic decrease in heat release and mass loss rates. The time to ignition initially decreased relative to the neat PP, then increased and surpassed it by a factor of 2 at 40%. These results paralleled those from conductivity/frequency measurements indicating that percolation occurred. Hence thermal phonon dissipation was effective for a slowly approaching heat front while contact was required for a rapidly approaching front. | 136 pages

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