Living Anionic Polymerization of 4‐(1‐Adamantyl)‐α‐Methylstyrene

Abstract

the living fashions to give the polymers of well-defined chain structures. It is noteworthy that the glass transition temperatures (T g s) of poly(AdS) and poly(Ad2S) are 234 and 232 °C. These T g values of the adamantyl-substituted polystyrenes are significantly higher than that of the parent polystyrene (T g = 100 °C). The highly symmetrical alicyclic adamantyl group has a negligible reactivity toward various chemical reagents, but it shows the drastic effect on enhancing the thermal properties of the resulting polymers. [29][30][31][32][33][34][35][36][37][38][39][40][41][42] Recently, the living anionic polymerizations of styrenes carrying reactive moieties, [41] and 1-adamantyl 4-vinylphenyl ketone [42] are also achieved. The rigid and bulky adamantyl substituents effectively hindered any serious side reactions of the nucleophilic initiators and the propagating carbanion with the electrophilic CO and CHN groups and realized the living anionic polymerizations. The high T g values of these polymers are respectively observed at 193 and 257 °C. Thus, the adamantyl substituents play very important roles to increase the T g s of the substituted polymers and to sterically protect the reactive functional groups from the serious side reactions.In this study, we newly designed and anionically polymerized an adamantyl-substituted α-methylstyrene derivative, 4-(1-adamantyl)-α-methylstyrene (AdαMS), in order to check the polymerizability of the monomer and the thermal properties of the resulting polymer. It is well known that α-methylstyrene derivatives usually undergo the equilibrium polymerization under the anionic conditions due to the low ceiling temperatures. [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58] The polymerization and depolymerization of α-methylstyrene derivatives reversibly occur under the equilibrium conditions. In addition, the poly(α-methylstyrene)s generally show higher T g values than those of the corresponding polystyrene derivatives and the ease of the chain degradation on heating. Results and DiscussionThe monomer, AdαMS, was synthesized from 1-bromoadamantane by the four-step reactions as shown in Scheme 1. In the final two steps, the Grignard reagent of 1-(4-bromophenyl) adamantane and acetone was reacted to give a corresponding tertiary alcohol. The following dehydration of the resulting alcohol in the presence of p-toluenesulfonic acid afforded

Extremely High Glass Transition Temperature Hydrocarbon Polymers Prepared through Cationic Cyclization of Highly 3,4‐Regulated Poly(Phenyl‐1,3‐Butadiene)

“…However, the fabrication of hydrocarbon polymers with high service temperature (Tg > 250 °C) remains a challenge. Hydrogenated poly(1,3‐cyclohexadiene) (Tg = 231 °C), hydrogenated high‐molecular‐weight polyindene (Tg = 267 °C), and poly(4‐(1‐adamantyl)‐α‐methylstyrene) (Tg = 274 °C) are hydrocarbon polymers with desirable temperature capabilities reported previously.…”

“…[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] However, the fabrication of hydrocarbon polymers with high service temperature (Tg > 250 °C) remains a challenge. Hydrogenated poly(1,3cyclohexadiene) (Tg = 231 °C), [26] hydrogenated high-molecular-weight polyindene (Tg = 267 °C), [27] and poly(4-(1-adamantyl)α-methylstyrene) (Tg = 274 °C) [8] are hydrocarbon polymers with desirable temperature capabilities reported previously.However, further increasing the Tg values of the aforementioned polymers by using only one strategy is difficult. Previously, we proposed a method combining strategies (2) and (3) to noticeably increase the Tg of hydrocarbon polymers.…”

“…Increasing efforts have been made to prepare high‐temperature hydrocarbon polymers in recent years. These strategies have involved: 1) the enhancement of the tacticity of the polymer chain, 2) the incorporation of bulky pendant groups in the side chain, and 3) the introduction of cyclic structures in the main chain . However, the fabrication of hydrocarbon polymers with high service temperature (Tg > 250 °C) remains a challenge.…”

“…Increasing efforts have been made to prepare high-temperature hydrocarbon polymers in recent years. These strategies have involved: 1) the enhancement of the tacticity of the polymer chain, [4,5] 2) the incorporation of bulky pendant groups in the side chain, [6][7][8] and 3) the introduction of cyclic structures in the 3,4-structure content reached 94% as determined from the 1 H NMR spectrum according to previous study [29] (Figure 1A), and this was also indicated by its 13 C NMR spectrum ( Figure S2, Supporting Information). The Tg of this P(1-PB) prepolymer was 82 °C.…”

Dienes and diamondoids: poly(2‐[1‐adamantyl]‐1,3‐butadiene) and random copolymers with isoprene via redox‐emulsion polymerization and their hydrogenation

“…Of the branched alkanes, diamondoids are highly symmetric and polycyclic, with a molecular geometry superimposable on the diamond lattice, and the smallest diamondoid, adamantane (tricyclo [3.3.1.13,7]decane), exhibits a remarkably high melting point above 220 C. 7 When incorporated as a pendant group in a range of olefins, [8][9][10][11][12][13][14][15][16][17][18] adamantane has imparted unique thermal and oxidative stability, low surface energy, high density and hydrophobicity, high refractive index and UV-transparency to polymers. 8,10,12 Tunable T g s have been observed by statistical copolymerizations varying the proportions of adamantyl-modified monomers with their parent monomers.…”