Dispersion Curves and Frequency Distributions of Isotactic Polypropylene

Abstract

Dispersion curves and a frequency distribution were calculated for isotactic polypropylene on the basis of a single-chain model using a valence force field previously reported in the literature. The obtained results provide useful information for the interpretation of the inelastic neutron scattering spectrum published by other authors. It is shown that calculations on the single-chain model account for practically all peaks in the experimentally determined frequency distribution. Most of these peaks arise from phase values which do not correspond to spectroscopically active motions.

Molecular Vibrations of Polymers

“…These include polymers of (a) commercial interest [polyethylene , poly(a-olefins) (39)(40)(41)(42)(43)(44)(45)(46)(47), other vinyl polymers (48)(49)(50)(51)(52)(53)(54), polytetrafluoroethylene (55)(56)(57)(58)(59)(60), polyethers (61)(62)(63)(64)(65)(66)(67)(68)(69)(70), polyamides (71)(72)(73)(74), polyvinylidene fluoride (75), polychloroprene (76), poly butadiene (77,78), and cellulose (79)] and of (b) biological interest [polyglycine (80)(81)(82)(83)(84)(85)(86)(87)(88)(89)…”

Microstructure studies of isotactic polypropylene under natural weathering by positron annihilation lifetime spectroscopy

“…In all spectra we could observe the characteristic absorption bands pattern of crystalline PP. The band at 998 cm −1 is characteristic band of the crystalline PP [28,29], and shows a gradual absorbance increase when the spectra of exposed surfaces of the weathered PP are normalized at the 974 cm −1 band (Fig. 3a), which implies an increase of the crystallinity for the weathered PP samples.…”

Structural characterization of linear polyethylene by infrared spectroscopy

“…However, for simple polymers, such as polyethylene, intermolecular interactions in the crystalline lattice have been found to affect the infrared response (32,33). For example, intermolecular interactions in the polyethy1eije crystal unit in splitting both the ethylene-scissoring (146O cm ) and the methylene-rocking (725 cm ) bands (19,20,33).…”