Synthesis of Core Cross-Linked Star Polymers Consisting of Well-Defined Aromatic Polyamide Arms

Abstract

Homopolymer-arm, block-arm, and miktoarm star polymers consisting of poly(N-octylm-benzamide) and poly(N-H-m-benzamide) were synthesized by means of a core cross-linking method. Macromonomers (MM) with the styryl terminal moiety were synthesized by chain-growth condensation polymerization of 3-(alkylamino)benzoic acid esters 1 in the presence of phenyl 4-vinylbenzoate as an initiator, and copolymerization with N,N 0 -methylenebis(acrylamide) as a divinyl monomer in the presence of 2,2 0 -azobis(isobutyronitrile) at 60 °C yielded the corresponding star polymers. In the synthesis of star polymers containing poly(N-H-m-benzamide) arms, the 4-(octyloxy)benzyl group on the amide nitrogen of the obtained star polymers was removed with trifluoroacetic acid. The number of arms per molecule, determined by multiangle laser light scattering, varied in the range of 36-100 depending on the N-alkyl group of 1 and the molecular weight of MM. The 1 H NMR spectra of the star polymers in dimethyl sulfoxide revealed that the poly(N-octyl-m-benzamide) segments and arms of the block-arm and miktoarm star polymers, respectively, were compactly packed at room temperature and became extended at higher temperatures.

N‐Alkylated Aromatic Poly‐ and Oligoamides

“…[31b,32] This type of polycondensation enables the synthesis of well-defined block copolyamides having different aminoalkyl side chains or different aryl substitution patterns (meta/para) [31a,33] as well as telechelic poly(p-benzamide)s (i. e. reactive polymers possessing reactive functional groups at the chain ends) [34] and crosslinked star polymers with aromatic polyamide arms. [35] It is worth noting that this type of polycondensation in the absence of an initiator was efficiently applied to access aromatic oligoamide macrocycles such as calix[3]amides. [36] One drawback of the chain-growth polymerization is the difficulty of accessing high molecular weight polymers since only polyaramides up to 24 000 g.mol À 1 could be formed.…”

“…To this end, the 4-(octyloxy)benzyl (OOB) or N-pmethoxybenzyl (PMB) groups were efficiently used as Nsubstituents to prevent aggregation during oligomer synthesis and to facilitate purification. [35,44] The protecting groups could then be removed to obtain highly interesting shape-persistent materials. This strategy has for example led to the development of strongly aggregating poly(benzamide)s with a rod-like conformation or rod-coil conformation when associated with PEG coil block polymers.…”

Synthesis of reactive three‐arm star‐shaped oligoimides with narrow molecular weight distribution

“…In the context of Yokozawa's and other researchers works, the use of the substituent effect in SSP synthesis is only an example of a more general methodological approach developed to obtain the well‐defined linear polycondensation‐type polymers such as polyamides, polyesters, polyethers, polyetherketones, and polyethersulfones. Also this approach was applied to obtain the polymers of different topological structure (block‐, graft‐copolymers, and SSP) . Another approach which has also been proposed by Yokozawa et al .…”

Functional Aromatic Polyamides

“…Ohisi et al synthesized a star polymer with controlled molecular mass and low polydispersity following a chain growth condensation strategy using 3-(alkylamino)-benzoic acid esters (condensation monomer) in the presence of phenyl 4-vinylbenzoate (condensation initiator, vinylic co-monomer) and N,N -methylenebisacrylamide (divinyl co-monomer) (Scheme 4, P9-P15) [24].…”