A versatile new method for structure determination in hyperbranched macromolecules

Kambouris, Peter; Hawker, Craig J.

doi:10.1039/p19930002717

Cited by 87 publications

(80 citation statements)

References 11 publications

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“…The synthesis of hyperbranched polyester of a similar structure but using the corresponding methyl ester as monomer and cobalt acetate as catalyst has been carried out by Hawker et al 11,12) The kinetics of the polycondensation as well as a detailed structure analysis of the product has been published recently 13) ; it was found that this polycondensation follows a strictly statistical conversion dependence of the degree of branching, which means that the reaction rates of both phenol groups are equal for each step. This leads to a degree of branching of 50% with one half of the functional groups located at the terminal units and one half at the linear units.…”

Section: Polyester Synthesismentioning

confidence: 98%

New coating systems based on vinyl ether- and oxetane-modified hyperbranched polyesters

Schmaljohann

Voit²,

Jansen

et al. 2000

Macromol. Mater. Eng.

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Section: Polyester Synthesismentioning

confidence: 98%

New coating systems based on vinyl ether- and oxetane-modified hyperbranched polyesters

Schmaljohann

Voit²,

Jansen

et al. 2000

Macromol. Mater. Eng.

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“…So far two techniques are generally used to determine the degree of branching of hyperbranched polymers: the first is based on NMR measurements of different building units 15 and the second method on degradation of hyperbranched backbones. 16 The former method is limited to polymers exhibiting differences in NMR resonance, and the latter is only applicable to those fully degradable polymers. Neither of the two techniques are applicable to the measurement of DB of poly[allyl methyl maleate-co-N-propyl maleimide].…”

Section: H Nmr Studiesmentioning

confidence: 99%

Preparation and glass transition temperature of hyperbranched poly[allyl methyl maleate‐co‐N‐propyl maleimide]

Liu

Wilén

2005

J of Applied Polymer Sci

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ABSTRACT:The kinetics and molecular weight averages of the hyperbranched polymers formed by the alternating copolymerization of equimolar allyl methyl maleate (AMM) and N-n-propyl maleimide (PMI) were investigated. The yields, molecular weight averages, and polydispersity indices as well as the branching degrees of the produced copolymers increased with increasing initiator concentrations and prolonged polymerization time. The trends of the experimental molecular weights as determined by size exclusion chromatography were in good agreement with the theoretical predictions. The molecular weight distribution indices fit the curve given by M w /M n ϭ 1/(1-x D ), and the molecular weights fit the curve given by M w ϭ 4076/ (1-x D ) 2 , where x D was the conversion of vinyl groups. DSC studies demonstrated a nonlinear relation of T g values to the reciprocal of molecular weight (M), and T g values decreased with the increase of molecular weight. For the T g values of highly branched polymers in high molecular weight range, a relation of T g ϭ T gϱ 0 ϩ k/M was obtained, where T gϱ 0 was obtained by extrapolating to infinite molecular weight and k was a constant. T gϱ 0 was 136°C, and k ϭ 2.9 for this work.

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“…First, the chain ends must remain intact during the degradation reactions, and the second, conversion into elementary subunits must be completed. 49 …”

Section: Synthesis Of Hbps T Higashihara Et Almentioning

confidence: 99%

Synthesis of hyperbranched polymers with controlled degree of branching

Higashihara

Segawa

Sinananwanich

et al. 2011

Polym J

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Hyperbranched polymers (HBPs) have attracted considerable attention during the past decade because of their intrinsic globular structures and unique properties, such as low viscosity, high solubility and a high degree of functionality, compared with linear analogs. As HBPs are generally prepared by one-pot polycondensation of an AB x monomer, where A and B represent two different functional groups, they are regarded as less-expensive alternatives to dendrimers. However, HBPs have randomly branched structures and their degree of branching (DB) is determined by statistics and only reaches B50%. Recently, several research groups have successfully synthesized a 100% DB without any defect mainly by condensation or addition reactions. These methods are based on a new concept in which the ratio of the rate constants, the first reaction rate constant (k 1 )/the second reaction rate constant (k 2 ) of an AB 2 monomer, can be controlled. Recent development in the synthesis of a linear polymer, that is, a 0% DB HBP, from an AB 2 monomer could make it possible to further precisely control the DB from 0 to 100% by using the same AB 2 monomer. In this review article, the backgrounds and methodologies for controlling the DB are described, especially focusing on recent advances in the synthesis of HBPs with a DB of 100, 0% and any percentage between 0 and 100%.

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A versatile new method for structure determination in hyperbranched macromolecules

Cited by 87 publications

References 11 publications

New coating systems based on vinyl ether- and oxetane-modified hyperbranched polyesters

New coating systems based on vinyl ether- and oxetane-modified hyperbranched polyesters

Preparation and glass transition temperature of hyperbranched poly[allyl methyl maleate‐co‐N‐propyl maleimide]

Synthesis of hyperbranched polymers with controlled degree of branching

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