| Abstract: | Monomer reactivity ratios and copolymerization parameters were determined for n-octadecyl acrylate and N-n-octadecylacrylamide with several monomers not previously reported. Values of Q and e for the long-chain acrylate now agreed more closely than before with the average of values for the lower acrylate homologs. The average polarity parameter for N-n-octadecylacrylamide still showed more electron withdrawal from the double bond (e = 0.42) than was expressed by the average literature value (e = ?0.10) for N-n-octylacrylamide. Because penultimate effects were absent in this work, the reason for the discrepancy seems to reside in the copolymer analysis. Reactivity ratios for oleyl and octadecyl acrylate with methyl methacrylate were similar. Coefficients for the relation between overall rates of copolymerization and composition were obtained on some systems by curve fitting with a computer. They generally showed a slight minimum. |
