ISSN:
0360-6376
Keywords:
Physics
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Monomer reactivity ratios, r1 and r2 were determined in the anionic copolymerizations of methyl methacrylate (MMA, M1) with ethyl (EtMA), isopropyl (i-PrMA), tert-butyl (t-BuMA), benzyl (BzMA), α-methylbenzyl (MBMA), diphenylmethyl (DPMMA), α,α-dimethylbenzyl (DMBMA), and trityl (TrMA) methacrylates (M2) by use of n-BuLi as an initiator in toluene and THF at -78°C. The order of the reactivity of the monomers towards MMA anion was DPMMA 〉 BzMA 〉 MMA 〉 EtMA 〉 MBMA 〉 i-PrMA 〉 t-BuMA 〉 TrMA 〉 DMBMA in toluene and TrMA 〉 BzMA 〉 MMA 〉 DPMMA 〉 EtMA 〉 MBMA 〉 i-PrMA 〉 DMBMA 〉 t-BuMA in THF. Except for the extremely low reactivity of TrMA and DPMMA in toluene due to steric hindrance, the order was explained in terms of the polar effect of the ester groups. A linear relationship was found between log (1/r1) and Taft's σ* values of the ester groups, where the ρ* value was 1.1. The plots of log (1/r1) vs. the 1Ha (cis to the carbonyl) and 13Cß chemical shifts of the monomers were also on straight lines. The polymer obtained in the copolymerization of MMA with TrMA in toluene by n-BuLi at -78°C was a mixture of poly-MMA and a copolymer, suggesting that there exist two kinds of growing centers.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1975.170130512
