The ¹H and ¹³C NMR spectra of an alternating ethene/maleic anhydride copolymer and the corresponding acid and sodium salt

Abstract

The 'H and '3C NMR spectra of an alternating ethene/maleic anhydride copolymer and the corresponding acid and sodium salt were reinvestigated with regard to the signals depending on the configuration of the succinyl unit. From these assignments a 85/15 ratio of threo-and erythrosuccinyl configurations was determined. Threo-and erythro-units are statistically distributed. Furthermore, signal splittings were observed due to microtacticity. Explanations are given for the signal fine structure. The polymer chain is atactic but a small degree of stereoregularity can be proved. T , values and nuclear Overhauser effect (NOE) factors were determined; they correspond to investigations on other polymers.

Thermotropic behavior of side-chain liquid-crystalline copolymers from maleic anhydride and mesogen-containing methacrylates

“…Copolymerizations of methacrylates and MA have been studied before and it has been found that the reactivity ratios of methyl methacrylate and MA were 3.10 -3.85 and 0.01 -0.02, respectively 24) . In agreement with these reactivity ratios, other studies have shown that MA does not homopolymerize under radical polymerization conditions 20,21) . Therefore, it is expected that the copolymerization of MA and methacrylates has a tendency towards alternation, which has already been observed before for the radical initiated copolymerization of MA and stearyl methacrylate 25) .…”

“…The same strategy may be applied to obtain SCLC polymethacrylates with adhesive properties. Contrary to the copolymerization of MA with 1-alkenes, which yields perfectly alternating copolymers 16,20,21) , copolymerization of MA with methacrylates is not strictly alternating due to the tendency of methacrylates to homopolymerize. MA does not homopolymerize under the applied conditions 20,21) .…”

“…Contrary to the copolymerization of MA with 1-alkenes, which yields perfectly alternating copolymers 16,20,21) , copolymerization of MA with methacrylates is not strictly alternating due to the tendency of methacrylates to homopolymerize. MA does not homopolymerize under the applied conditions 20,21) . Therefore, the MA content of the MA-methacrylate copolymer can be influenced by changing the amount of MA in the monomer feed and, consequently, both backbone flexibility and mesogen density can be altered.…”

Isomerisation of Erythro‐ and Threo‐Succinyl Units in Alternating Alkene‐Maleic Acid Copolymers: A Promising Route to New Microstructures

“…The radical polymerisation of MAn with olefins results in limited erythro-contents of about 12-17% for ethene [7][8][9] and 20-33% for propene [8] as comonomer. No erythrounits were found for the isobutene copolymer.…”

“…NMR spectroscopy allows this ratio to be determined very easily for the ethene-MAn copolymer and its acid and salt forms. [9] Therefore, this copolymer was chosen for our first investigations. Because the 2,3-dialkyl succinic anhydride group is unstable under experimental conditions (T !…”