Reaction, chain, copolymer molar mass fraction

The compositions and absolute molecular weights reported in Table 1 were determined by NMR and GPC-MALS, respectively. Poly(apidic acid-co-octanediol-co-sorbitol) (PAOS) containing (1, 5, 12 and 18) % (mol fraction) sorbitol units have relative molar mass values that are similar (43,000 to 60,000). However, the 27 % (mol fraction) copolymer has a relative molar mass value of 117,000. We believe that the high molecular weight reported for 27 % PAOS is due to branching and an increased propensity for interchain coupling reactions that occur between non-chain end repeat units. 

FIGURE 13.4 Using data from Figure 13.3, the fractional conversion of Am and VB are shown. A two-phase reaction occurs in which copolymer of Am and VB is produced up until 5500 s, after which homopolymers of Am form. Hence, a blend of copolyelectrolyte and Am homopolymer results. Also shown are the cumulative M and M. according to Equation 11.7. The mass of the polymer chains jumps up once the final Am homopolymerization period begins. Reprinted (adapted) with permission from Alb AM, Paril A, Catalgil-Giz H, Giz A, Reed WF. Evolution of composition, molar mass, and conductivity during the free radical copolymerization of polyelectrolytes. J Phys Chem B 2007 111 8560-8566. 2007 American Chemical Society. 

---