Structure and polydispersity of some poly(methyl methacrylates) prepared by different methods

✍ Scribed by Moustafa, A. B. ;Badran, A. S. ;Ebdon, J. R. ;Hunt, B. J.

• Book ID: 105334043
• Publisher: John Wiley and Sons
• Year: 1982
• Weight: 245 KB
• Volume: 20
• Category: Article
• ISSN: 0360-6376
• DOI: 10.1002/pol.1982.170201016

✦ Synopsis

Abstract

Poly(methyl methacrylate) has been prepared under various conditions of monomer, initiator, reaction medium, and temperature. All the ^13^C‐NMR spectra for the polymers obtained were those to be expected for radically initiated poly(methyl methacrylates) of conventional, slightly syndiotactic‐rich microstructures prepared at normal temperature. The spectra were found to be very similar to that for a radical poly(methyl methacrylate) first analyzed by Inoue et al.,^8^ and to those of poly(methyl methacrylates) prepared in earlier experiments of this general type. The ratios of isotactic (mm) to heterotactic (mr and rm) to syndiotactic (rr) triads were found to be close to 5:34:61. It can be concluded from the ^13^C‐NMR spectra that the propagation steps in these polymerizations are of conventional radical type, and are uninfluenced from the steric point of view by nature of the polymerization medium by the presence of the various additives. The polydispersity for some poly(methyl methacrylate) samples determined by gel permeation chromatography was found here to vary rather widely and ranges between 1.9 and 7.9.