Dispersion-driven interphase engineering and quantitative stress transfer in chemically inert PTFE/MWCNT...

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Interphase engineering in chemically inert polymer nanocomposites is challenging due to difficulty separating physical confinement from chemical functionalization.
• Non-functionalized polytetrafluoroethylene/multi-walled carbon nanotube (PTFE/MWCNT) nanocomposites serve as a model system to study these effects.

Purpose of the Study:

• To establish a quantitative framework for understanding dispersion-interphase-structure relationships in inert nanocomposites.
• To investigate the role of physical confinement and dispersion on stress transfer and crystallization behavior.

Main Methods:

• Systematic variation of MWCNT loading in PTFE.
• Raman spectroscopy to analyze interfacial strain and bonding.
• X-ray diffraction (XRD) with FWHM and Scherrer analysis for crystallite size.
• Differential Scanning Calorimetry (DSC) for crystallinity and melting temperature.

Main Results:

• Raman spectroscopy showed reduced ID/IG ratios and G-band upshifts, indicating interfacial strain (∼0.22%) due to physical confinement.
• XRD revealed crystallite enlargement at intermediate loadings, with maximum relative crystallinity at 10:2 PTFE:MWCNT.
• Higher loadings led to re-agglomeration and reduced crystalline ordering, despite increased melting temperatures (328-334 °C).

Conclusions:

• Nanotube dispersion significantly influences interphase evolution and acts as a thermodynamic regulator in fluoropolymer nanocomposites.
• Physical confinement, driven by dispersion, is key for stress transfer and crystallization behavior in inert CNT/polymer systems.
• This research provides a strategy for interphase engineering in chemically inert systems without requiring chemical modification.