Processing and characterization of extruded PET and its r-PET and MWCNT nanocomposite thin films by spin coating

摘要

The objective of the present study was basic understanding of the formation of thin film morphology by spin coating using reorganized polyethylene terephthalate (r-PET) and multiwalled carbon nanotubes (MWCNTs) as fillers in PET. A study of the correlation between physical properties of the PET films and its surface morphology was carried out using atomic force microscopy-based power spectral density (PSD) analysis. No significant work of surface analysis, using PSD of thin films of PET has been reported till date. Dilute solution of PET, PET with 3 wt% (r-PET) and PET with 3 wt% (2 wt% r-PET + 1 wt% MWCNT) filler were prepared using trifluoroacetic acid (TFA) as a solvent and thin films were fabricated on glass substrate by the optimized spin coating technique. Preparation of r-PET and r-PET + MWCNT fillers was obtained by the precipitation method using TFA as a solvent and acetone as an antisolvent. The samples before spin coating were extruded and for comparison, a film of non-extruded PET was also prepared. Structural studies by Fourier transform infrared and X-ray diffraction show higher degree of crystallinity in r-PET and decrease in chain entanglements. Owing to the crystallizing behaviour of r-PET, it allows better dispersion of MWCNT in the polymer matrix as compared with PET. The samples with fillers of MWCNT show more compact and unique mesh-like globular structure, indicating application for electromagnetic shielding foams and fibres.