Syntheses and properties of hyperbranched polybenzoxazole by thermal cyclodehydration of hyperbranched poly[o‐(t‐butoxycarbonyl)amide] via A₂ + B₃ approach

Abstract

The syntheses and properties of hyperbranched poly(o‐hydroxyamide) [poly(HAB‐BCC)‐ABP], poly[o‐(t‐butoxycarbonyl)amide] [poly(HAB‐BCC)‐ABP‐t‐BOC], and polybenzoxazole [poly(HAB‐cycloBCC)] were examined. Poly(HAB‐BCC)‐ABP was obtained from the polycondensation reaction of 3,3‐dihydroxy‐4,4′‐diaminobiphenyl (HAB) as an A2‐monomer and 1,3,5‐benzenetricarboxylchloride (BCC) as a B3‐monomer with 2‐amino‐4‐t‐butylphenol (ABP) in NMP in the presence of pyridine for 24 h. The reaction of poly(HAB‐BCC)‐ABP and di‐t‐buthylcarbonate (DiBOC) was performed to obtain the corresponding poly(HAB‐BCC)‐ABP‐t‐BOC with pendant t‐BOC groups. The thermal cyclodehydration of poly(HAB‐BCC)‐ABP‐t‐BOC was carried out in the film sate at 400 °C, affording the poly(HAB‐cyclo‐BCC) in quantitative yield. Furthermore, the solubilities and thermal properties of these polymers were examined. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3640–3649, 2006

Synthesis of Hyperbranched Polymers via Metal‐Free ATRP in Solution and Microemulsion

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typically could be produced in one pot via step-growth polymerization of multifunctional AB m (m ≥ 2) monomers, [7][8][9][10][11][12][13] step-growth copolymerization of A n and B m monomers (e.g., A 2 + B 3 ), [14][15][16] chaingrowth polymerization of AB m (m ≥ 2) monomers, [17][18][19] chain-growth copolymerization of divinyl cross-linkers, [20][21][22][23][24][25][26] selfcondensing vinyl polymerization (SCVP) of polymerizable initiators (inimers), [27][28][29][30][31][32][33][34][35] or polymerizable transfer agents (transmers). [36][37][38][39][40] It is important to note that any of these methods could produce hyperbranched polymers and randomly branched polymer as their difference lies in the fraction of branching unit incorporated into the polymer backbone.

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Synthesis of hyperbranched polybenzoxazoles and their molecular composites with epoxy resins

“…16,17 The introduction of hyperbranched structure constitutes another facilitate approach to tailor the physicochemical properties of linear polymers. [27][28][29] For instance, Kudo et al synthesized HBPBOs in two steps via the thermal cyclodehydration of a hyperbranched poly(o-hydroxyamide), which was preprepared by A 2 1B 3 strategy. [18][19][20] Owing to their globular and porous structure, HBPs generally exhibit better solubility and processibility than their linear counterparts because such configuration could lower the entanglement or packing of polymer chains.…”

“…Hyperbranched polymers (HBPs) are a special class of dendritic polymer, but unlike perfect dendrimers, HBPs can be synthesized via one-step polymerization, which offers great promising for large-scale preparation. 27 Unfortunately, the HBPBOs were still not soluble in common organic solvents. The lowered intermolecular interaction also offers possibility to tune the electronic properties, transporting properties, and optical properties of HBPs.…”

Synthesis of hyperbranched polyacetals via a n + b2 -type polyaddition (n = 3, 8, 18, and 21): Candidate resists for extreme ultraviolet lithography

“…Further, the A n + B m ‐type method has significant advantages for industrial applications, because commercially available monomers can be used, and soluble hyperbranched polymer can be synthesized in high yield by control of the polymerization conditions, such as monomer feed ratio, monomer concentration, and reaction time. Many hyperbranched polymers have been reported: hyperbranched polyamide, hyperbranched polyesters, hyperbranched polyimide, hyperbranched polybenzoxazole, and hyperbranched polyacetal . Very recently, Ramakrishnan et al reported the synthesis of a photodegradable hyperbranched polyacetal by means of an AB 2 ‐type method.…”