Poly(styrene-co-N-butylmaleimide) macroinitiators by controlled autopolymerization and related block copolymers

Abstract

Autopolymerization of styrene-N-butylmaleimide mixtures at 125 or 140°C in the presence of a stable nitroxyl radical [2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO)] was found to proceed in a pseudoliving manner. Unimolecular initiators, which were originated by trapping self-generated radical species with TEMPO, took part in the process. Under the studied experimental conditions, the TEMPO-controlled autopolymerization with a varying comonomer ratio provided virtually alternating copolymers of narrow molecular weight distributions. The molecular weights of the copolymers increased with conversions. The obtained styrene-N-butylmaleimide copolymers containing TEMPO end groups were used to initiate the polymerization of styrene. The polymerization yielded poly(styrene-co-N-butylmaleimide)-polystyrene block copolymers with various polystyrene chain lengths and narrow molecular weight distributions. The compositions, molecular weights, and molecular weight distributions of the synthesized block copolymers and the initial poly(styrene-co-N-butylmaleimide) precursors were evaluated using nitrogen analysis, gel permeation chromatography, and 1 H-and 13 C-NMR spectroscopy.

New mesogenic maleimide-styrene copolymers via N-oxyl mediated free radical copolymerization

“…Copolymerizations of N-alkyl-or N-phenylmaleimides with St in bulk or solution by 'controlled' / living radical polymerization methods like ATRP [20,21] or SFRP [22][23][24][25][26] revealed that alternating copolymers or block copolymers with controlled molecular weight and low polydispersities can be prepared.…”

Tailored Polymer Microstructures Prepared by Atom Transfer Radical Copolymerization of Styrene and N‐substituted Maleimides

“…For instance, the first example of nitroxide mediated alternating copolymerization of styrene and N-butyl maleimide was published by Lokaj and co-workers in 1999. [65] Shortly after, the same group described the NMP of styrene and MAh. [66] In these two examples, TEMPO was used as control agent (i.e., first generation nitroxide) and therefore the molecular weight distributions of the formed alternating copolymers were relatively broad.…”

Functional Polymers with Controlled Microstructure Based on Styrene and N ‐Substituted Maleimides

“…Schmidt-Naake et al [55] reported the copolymerization of styrene and various N-substituted maleimides, that is, N-cyclohexyl maleimide [54,55], N-butyl maleimide, and N-phenyl maleimide in the presence of the stable free radical 2,2,6,6-tetramethylpiperidin-1-yloxyl (TEMPO) initiated by benzoyl peroxide, while Lokaj et al studied the copolymerization of styrene with maleimide [56], N-butyl maleimide [57], or N-phenyl maleimide [58] in the presence of TEMPO and initiated by autopolymerization (i.e., styrene thermal initiation). As in the case of conventional radical polymerization, an alternating copolymer was observed, but the polymerization technique employed allowed better control over the molecular weight and molecular weight distribution.…”