A detailed analysis of the Raman spectrum of syndiotactic polystyrene, sPS, in the region 600−850 cm-1 has been undertaken. As sPS exhibits considerable polymorphism, spectra of various preparations including melt-crystallized sPS (α/β form), solvent-crystallized sPS (γ/δ forms), and quenched glassy material were studied. The ν1 vibration of the phenyl ring (ring breathing mode) has been shown to manifest itself through the presence of two peaks resulting from local conformational changes in the alkyl backbone. The peak centred around 773 cm-1 has been assigned to an all-trans backbone sequence whereas the higher frequency feature at ∼798 cm-1 is attributed to mixed trans/gauche conformations. For comparison the spectrum of atactic polystyrene was also studied, and the presence of a weak shoulder is assigned to a syndiotactic all-trans component within the polymer. Further study of a cross section of molded material exhibiting a skin/core structure reveals the continuous way in which the relative size, po...

Raman Vibrational Studies of Syndiotactic Polystyrene. 1. Assignments in a Conformational/Crystallinity Sensitive Spectral Region

Luminescent probe studies of the microstructure and mobility of solid polymers

Confinement, composition, and spin-coating effects on the glass transition and stress relaxation of thin films of polystyrene and styrene-containing random copolymers: Sensing by intrinsic fluorescence

The influence of surface properties on sliding contact temperature and friction for polyetheretherketone (PEEK)

New Stereochemical Assignments of 13C NMR Signals for Predominantly Syndiotactic Polystyrene

Intramolecular excimer formation in polystyrene model molecules

Fourier transform infra-red and birefringence studies of orientation in uniaxially-stretched poly(2,6-dimethyl 1,4-phenylene oxide) — atactic polystyrene blends

The study of 2,4-diphenylpentane (1), 2,4,6-triphenylheptane (2) and 2,4,6,8-tetraphenylnonane (3) by 13C NMR allows to compare the various chemical sequences of these compounds in terms of their chemical shifts.



Methyl, methylene and aromatic C1 carbons are particularly sensitive to tacticity. Moreover, from the aromatic C1 chemical shifts it is possible to propose an assignment of the corresponding pentads of polystyrene.

Analysis of carbon‐13 nuclear magnetic resonance spectrum of polystyrene by means of model molecules

Molecular dynamics of polystyrene model molecules: Solvent effects on intramolecular excimer formation in 2,4-diphenylpentanes

Conformational energies have been calculated for isotactic, syndiotactic and heterotactic 2,4,6-triphenylheptane, giving the most likely states and the conformational paths between them. The ultrasonic attenuation of these compounds has been investigated as a function of temperature and frequency. A single relaxation is observed for isotactic and syndiotactic isomers and has been assigned to isomerism between the helix tg+tg+(or g–tg–t) and the transition form g–ttg+ for the isotactic, and between tttt and ttg+g+(or g–g–tt) conformations for the syndiotactic isomer. Two relaxation processes were needed for the heterotactic isomer, each involving one part of the molecule; the rotational isomerism of the meso diad is between g–ttt (or tg+tt) and tttt conformations, while the racemic diad involves a relaxation between g–ttt and g–tg+g+ conformations.

Bruno Jasse

Papers

Intramolecular excimer formation in polystyrene model molecules

Fourier transform infra-red and birefringence studies of orientation in uniaxially-stretched poly(2,6-dimethyl 1,4-phenylene oxide) — atactic polystyrene blends

Analysis of carbon‐13 nuclear magnetic resonance spectrum of polystyrene by means of model molecules

Molecular dynamics of polystyrene model molecules: Solvent effects on intramolecular excimer formation in 2,4-diphenylpentanes

Molecular dynamics of polystyrene model molecules. Conformational energy and ultrasonic relaxation of 2,4,6-triphenylheptane