Light‐scattering study of polyacrylonitrile solution

Abstract

Light‐scattering measurements of polyacrylonitrile (PAN) prepared by aqueous suspension polymerization and solution polymerization were made in both dimethylformamide (DMF) and γ‐butyrolactone (γ‐BL). The following relations between the intrinsic viscosity [η] (in deciliters per gram) and the weight‐average molecular weight were obtained: [η] = 3.35 × 10−4 M̄w0.72 (in DMF at 30°C.) and [η] = 4.00 × 10−4 M̄w0.69 (in γ‐BL at 30°C.). The relation in DMF is in agreement with the results of many other researchers, but differs from the results of Bisschops et al. and Peebles. Analysis of the results by the recent viscosity theory reported by Inagaki et al. indicates that the steric factor σ is 2.17 on PAN in both DMF and γ‐BL. It is found that the root‐mean‐square radius of gyration of the chain measured by light scattering 〈S2〉w1/2 (LS) is in good agreement with the root‐mean‐square radius of gyration of the chain calculated by using the viscosity theory of Inagaki et al. 〈S2〉w1/2 (vis) in both DMF and γ‐BL. Relations between the root‐mean‐square radius of gyration of the chain (in Angstroms) in DMF and γ‐BL and the molecular weight were obtained: 〈S2〉w1/2 = 7.94 × 10−2 M̄w0.66 (in DMF) and 〈S2〉w1/2 = 2.19 × 10−1 M̄w0.57 (in γ‐BL). From the estimation of the second virial coefficient A2 and the value of B obtained from viscosity theory, it is found that DMF is a better solvent than γ‐BL.

Polymerization of acrylonitrile catalyzed by single yttrium tris(2,6‐di‐tert‐butyl‐4‐methyl phenolate)

“…The intrinsic viscosity of polymer was determined by Ubbelodhe‐type viscometer in DMF at 30 °C and the weight‐average molecular weights ( M w ) were calculated by the following equation:12 …”

Simultaneous DSC/TG analysis on the thermal behavior of PAN polymers prepared by aqueous free-radical polymerization

“…The viscosity average molecular weight (M η ) of the PAN polymers was calculated from [η] according to the following equation [24]. …”

Cobalt(III)‐mediated microemulsion polymerization of acrylonitrile: Kinetics and particle morphology

“…The viscosity average molecular weights of the purified polymers were determined by using a Ubbelohde viscometer in pure DMF at 30°C, with the equation 23 ͓͔ ϭ 3.335 ϫ 10 Ϫ4 M V 0.72 Particle size was investigated by TEM (Joel JEM 2000-Ex11). Samples were prepared by dropping highly diluted latex on a carbon-coated copper grid and dried in a desiccator at room temperature.…”