Investigation of the Effects of Temperature and Strain on the Damping Properties of Polycarbonate/Multiwalled Carbon Nanotube Composites

Abstract

The effects of temperature and strain on the free volume and damping properties of polycarbonate/multiwalled carbon nanotube (PC/MWCNT) composites were investigated by positron annihilation lifetime spectroscopy and dynamic mechanical thermal analysis. The damping dependence on temperature indicated that the damping factors remain at a low constant value in the polymer glassy state and increase rapidly in the glass-transition area. During the glass-transition area, a direct linear relationship between the fractional free volume and the damping has been obtained using the WilliamsÀLandelÀFerry equation based on the free volume theory, which indicates that the free volume plays an important role in determining the damping property. The strainÀdamping experiments reveal that a high damping factor is still obtained. A "stickÀslip" model has been used to analyze the damping dependence on strain for PC/MWCNT composites, which reveals a damping mechanism of interfacial slip between the MWCNTs and the matrix.

Effects of carbon nanotubes on polymer physics

“…65 In the latter study, T g increased by $3 C at 1% nanotube content followed by a decrease while solvent extraction of the polycarbonate showed that the molecular weight was much lower for the samples processed with filler than without filler. Two other studies 66,67 showed an immediate decrease with added nanotubes followed by a plateau while another showed a decrease then an increase, 68 qualitative behaviors that are difficult to rationalize via a degradation mechanism.…”

Tough semiconductor polycarbonate/multiwalled carbon nanotubes nanocomposites by rubber modification

“…Both increases [18,46,47] and decreases [35,[48][49][50][51] have been observed in the T g of the PC based NCs upon MWCNT addition. In this study the T g of the NCs increased slightly.…”

Enhanced Solid Particle Erosion Properties of Thermoplastic Polyurethane‐Carbon Nanotube Nanocomposites

“…On one hand, the addition of CNTs changes the molecular chain configuration in the TPU matrix, and the originally tightly packed molecular chain packing pattern is disturbed, and a large amount of space for the molecular chain to move freely is formed around the CNTs, that is, the free volume increases. On the other hand, an increase in the free volume causes an increase in the mobility of a part of the molecular chain to lower the T g . In other words, the CNTs increased the distance between the soft segments of the TPU chains, resulting in an increase in free volume and easy movement of the segments, so the T g tends to decrease.…”