Spectroscopic elucidation of structure-property relations in filaments melt-spun from amorphous polymers

Abstract

Melt spinning and drawing of amorphous cyclo-olefin and co-polyamide polymeric materials were performed to develop mono-component continuous filaments. Raman spectroscopy was employed to assess the effect of a static bending deformation on the microstructure of the filaments. Spectra stemming from the fiber regions under tensile and compressive loading do not show any appreciable shift of their vibrational bands as a function of applied strain. The bent filaments manage to redistribute strains without any stretching or buckling of polymer chains associated with peak shifting in the Raman spectrum. The influence of fiber draw ratio on the degree of molecular ordering was demonstrated by means of polarized Raman spectroscopy. An increase in draw ratio leads to a variation of the polarization ratio for spectroscopic bands located along the polymer backbone. We observed a correlation between the polarization ratio of these vibrational bands and the macroscopic tensile modulus of the material.

Fabrication and spectroscopic characterization of graphene transparent electrodes on flexible cyclo-olefin substrates for terahertz electro-optic applications

“…A rich variety of spectral features is observed, the strongest of which lies in the interval 2800-2950 cm −1 and stems from the characteristic C-H stretching vibrations (ν CH ), common in hydrocarbons but also observed in Raman spectra of the same type of Zeonor films [42]. More importantly, a series of closely spaced or overlapping features is evidenced below 1500 cm −1 , attributed to rocking, twisting, and bending vibrations, the most characteristic being the CH 2 bending (δ CH2 ) and rocking (2ρ CH2 ) modes [43], which in our measurements peaked at 1446 cm −1 .…”

Melt-Spun Fibers for Textile Applications

“…The morphology of solid-state polymers typically fluctuates continuously between ideal crystalline and fully amorphous states, where “amorphous” is widely used in polymer science to mean non-crystalline [ 62 , 63 ]. Polymers with irregular molecular structures cannot crystallize under any condition, so the only important morphological feature that can be changed through processing is molecular orientation [ 64 ].…”

Selective Swelling of Stretched Block Copolymer Hollow Fibers for Upgraded Membrane Performance

“…Unlike the crystallizable polymers described above, PSF- b -PEG represents a two-phase structure in which the majority PSF block is an amorphous polymer while the minority PEG block can crystallize. Thus, during the stretching process, the matrix formed from the amorphous but rigid PSF may have a significant impact on the crystallization of the flexible PEG block . Besides, the swelling behavior of the oriented molecular chains caused by stretching in selective solvents is also unclear.…”

“…Thus, during the stretching process, the matrix formed from the amorphous but rigid PSF may have a significant impact on the crystallization of the flexible PEG block. 28 Besides, the swelling behavior of the oriented molecular chains caused by stretching in selective solvents is also unclear. Thus, in this work, stretching is introduced to the melt-spun PSF-b-PEG hollow fibers followed by selective swelling in order to regulate the initial membrane dimensions as well as membrane thickness and consequently to improve the separation performance of the HFMs.…”