Molecular Vibrations of Polymers

Fanconi, Bruno

doi:10.1146/annurev.pc.31.100180.001405

Cited by 16 publications

(2 citation statements)

References 78 publications

(107 reference statements)

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“…These peak assignments are listed in table 1. These peaks are attributed to different molecular vibrations, which are in agreement with similar assignments made by other researchers [33][34][35][36].…”

Section: Lo Phonon Vibrons (Vibrations)supporting

confidence: 92%

Spectroscopic analysis of CdCl₂ doped PVA–PVP blend films

Baraker

Lobo

2017

Can. J. Phys.

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Abstract:The changes in molecular chemical structure of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), caused by doping PVA-PVP blend with cadmium chloride (CdCl 2 ), have been studied using UV-Visible (UV-Vis) spectroscopy, Fourier Transform Raman spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy. The formation of cadmium nano-structures and microstructures in CdCl 2 doped PVA-PVP blend has been visualized using Scanning Electron Microscopy (SEM), in the range of doping levels varying from 0.5 wt% up to 10.2 wt% (doping level in weight percentage). The incorporation of dopant in PVA-PVP blend is confirmed using Energy Dispersive x-ray Spectroscopy (EDS). The optical absorbance (UV-Vis) spectra of PVA-PVP blend films doped with CdCl 2 from 0.5 wt% up to 2.2 wt%, showed a prominent absorption hump with peak at the wavelength 370 nm, in addition to other intermediate energy bands caused by the interactions of CdCl 2 with molecules of PVA and PVP. The photo-luminescence (emission/ fluorescence) spectra show significant quenching of fluorescence in CdCl 2 doped PVA-PVP blend films. Analysis of FTIR and Raman spectra suggest the possible modes of interaction of cadmium ions (Cd 2+ ) and chlorine ions (Cl -) with reactive functional groups (C-N, hydroxyl and carbonyl groups) of polymeric molecules in the blend. A reaction scheme for interaction of CdCl 2 with PVA-PVP blend is proposed, on the basis of spectroscopic studies on these films.

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Section: Lo Phonon Vibrons (Vibrations)supporting

confidence: 92%

Spectroscopic analysis of CdCl₂ doped PVA–PVP blend films

Baraker

Lobo

2017

Can. J. Phys.

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“…After 30 days hydrolysis of PBS, a remarkable decrease of COC and CO absorption intensity was observed. These reductions in absorption intensity were due to lowering of the molecular weight and deterioration of the chemical structure by hydrolysis after being exposed to moisture and heat …”

Section: Resultsmentioning

confidence: 99%

Hydrolytic degradation of biodegradable polyesters under simulated environmental conditions

Muthuraj

Misra

Mohanty

2015

J of Applied Polymer Sci

117

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In this study, the durability of poly(butylene succinate) (PBS), poly(butylene adipate-co-terephthalate) (PBAT), and PBS/ PBAT blend was assessed by exposure to 50 C and 90% relative humidity for a duration of up to 30 days. Due to the easy hydrolysis of esters, the mechanical properties of PBS and PBAT were significantly affected with increasing conditioning time. The PBS, PBAT, and PBS/PBAT showed an increase in modulus as well as a decrease in tensile strength and elongation at break with increased exposure time. Furthermore, the impact strength of PBAT remains unaffected up to 30 days of exposure. However, it was clearly observed that the fracture mode of PBS/PBAT changed from ductile to brittle after being exposed to high heat and humid conditions. This may be attributed to the hydrolysis products of PBS accelerating the degradation of PBAT in the PBS/PBAT blend. The differential scanning calorimetry results suggested that the crystallinity of the samples increased after being exposed to elevated temperature and humidity. This phenomenon was attributed to the induced crystallization from low molecular weight polymer chains that occurred during hydrolysis. Therefore, low molecular weight polymer chains are often favored to the crystallinity enhancement. The increase in crystallinity eventually increased the modulus of the conditioned samples. The enhanced crystallinity was further confirmed by polarizing optical microscopy analysis. Moreover, the hydrolysis of the polyesters was evaluated by scanning electron microscopy, rheology, and Fourier transform infrared spectroscopy analysis.

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