Radical copolymerization ofN-alkylmaleimides with isobutene and the properties of the resulting alternating copolymers

Abstract

Radical copolymerization of N‐methylmaleimide (MeMI) as well as other N‐alkylmaleimides (RMI) and isobutene (IB) was carried out with 2,2′‐azobis(isobutyronitrile) as an initiator at 60°C. The initial rate of the copolymerization (Rp) was dependent on the monomer composition and was maximum at the 40 mol % of MeMI in the feed. A solvent effect on the Rp and the monomer reactivity ratio was observed in this copolymerization system, i.e., copolymerization in chloroform produced a higher Rp and an alternating tendency compared with those in dioxane (rMeMI = 0.14, r1B = 0 in chloroform and rMeMI = 0.47, r1B = 0 in dioxane). The alternating copolymer of RMI and IB shows a high glass transition temperature (Tg) and excellent thermal stability, e.g., the Tg and the thermal decomposition temperature (Td) were 152 and 363°C, respectively, for the alternating copolymer of MeMI and IB. Both the Tg and Td increased as the concentration of the MeMI unit in the copolymers increased. Colorless transparent sheets were obtained from press molding the alternating copolymers. They showed excellent mechanical and optical properties. © 1996 John Wiley & Sons, Inc.

Thermal Properties of N-Phenylmaleimide-Isobutene Alternating Copolymers Containing Polar Groups to Form Intermolecular and Intramolecular Hydrogen Bonding

“…[28][29][30] Considering a steric factor, poly(2-alt-IB) was expected to show the highest T g value due to the steric hindrance, but actually this was not true. In a previous paper, 18 the T g values of poly(XPhMI-alt-IB) containing 2-methyl and 2,6-dimethyl substituents in the Nphenyl group were reported to be 207 and 237 C, respectively. The T g value (222 C) for poly(2-alt-IB) in the present study was higher than that of the 2-methyl-substituted one.…”

“…The alternating repeating structure of the copolymers was confirmed by 1 H NMR spectroscopy (Figure 1), similar to the results for the copolymerization of N-alkyl-and N-(alkyl-substituted phenyl)maleimides with IB. 13,18 The steric hindrance of the substituents in the ortho-substituted XPhMIs decreases their propagation rate constants and relative monomer reactivity during homo-and copolymerizations, respectively, according to the number and size of the substituents. 14,26,27 Consequently, alternating copolymers are readily produced during the copolymerization of the ortho-substituted XPhMIs with IB because of a lack of the homopolymerizability of IB.…”

“…4,[15][16][17] In 1996, Doi and coworkers reported that the alternating copolymerization of N-alkylmaleimides (RMI) with isobutene (IB) [poly(RMI-alt-IB)] produces high molecular weight copolymers with excellent thermal properties, as well as excellent mechanical and optical properties. [18][19][20][21] Poly(RMI-alt-IB)s are soluble in a larger number of organic solvents and had a moderate softening temperature. The processing of poly-(RMI-alt-IB)s can be easily carried out for the fabrication of polymer films, sheets, and molded products.…”

Synthesis and Characterization of Thermoresistant Maleimide Copolymers and their Crosslinked Polymers

“…This indicated that the AAB-type sequence was predominantly produced during the copolymerization of the RMIs with bulky DIB under the penultimate unit control, [17][18][19] being different from the formation of alternating copolymers with isobutene under terminal control. [11][12][13] The AMI content varied in a range of 12-43 mol% in the copolymers. The carbon-to-carbon double bond of the maleimide ring had a reactivity 10 3 times higher than that of the allyl moiety in the side group, resulting in the selective participation of the maleimide double bonds in propagation during the copolymerization.…”

“…[7][8][9][10][11] Especially, the copolymerization of the RMIs with isobutene provided an alternating copolymer with excellent thermal stability, high transparency, and high modulus and strength. [12,13] The introduction of polar groups and cyclic structures into the olefin repeating units led to further increases in their thermally stability and the T g values. [14][15][16] Recently, we demonstrated that the copolymerization of the RMIs provided copolymers with finely controlled structures in the 1:1 alternating and 2:1 sequence-controlled fashions, depending on the steric bulkiness and conjugated structure of olefin and styrene derivatives.…”