13C n.m.r. and g.p.c.—low-angle laser light scattering measurements on polyacrylonitrile prepared by urea clathrate polymerization in the solid state for the optimization of tacticity

• Published in: Polymer (Guilford) Vol. 36; no. 12; pp. 2343 - 2346
• Main Authors: Minagawa, Masatomo, Takasu, Tōru, Shinozaki, Satoshi, Yoshii, Fumio, Morishita, Norio
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1995; Elsevier
• Subjects: Applied sciences; Exact sciences and technology; isotatic configuration; Organic polymers; Physicochemistry of polymers; polyacrylonitrile; Properties and characterization; Structure, morphology and analysis; urea clathrate polymerization; isotatic configuration; urea clathrate polymerization; polyacrylonitrile; Urea; Acrylonitrile polymer; Molecular weight distribution; Isotactic polymer; Clathrate; Stereospecificity; Solid polymerization; Experimental study; Stereospecific polymerization; Molecular weight
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/0032-3861(95)97331-9

The molecular weight and molecular weight distribution of isotactic polyacrylonitrile (PAN) prepared by urea clathrate polymerization in the solid state were studied by the g.p.c.—low-angle laser light scattering (l.a.l.l.s.) method. The experimental details of this method for PAN are described. Measurements were carried out on three different kinds of urea clathrate PAN, and the results were compared with those of free-radical PAN (i.e. prepared using the aqueous redox slurry system). The characteristics of the urea clathrate PAN were (1) an asymmetrical shape in the g.p.c.—L.a.l.l.s. curve and (2) a remarkable contribution of the lower-molecular-weight component to the high stereoregularity (>80%) of the sample. An experimental prediction for the solid-state synthesis of a perfectly stereoregular PAN sample (isotacticity of 100%) has been derived from a combination of the g.p.c.—l.a.l.l.s, and 13C n.m.r. results.