Effect of the degree of branching on the glass transition temperature of polyesters

Khalyavina, Anna; Häußler, Liane; Lederer, Albena

doi:10.1016/j.polymer.2012.01.020

Cited by 64 publications

(67 citation statements)

References 17 publications

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“…A major accelerating effect was a result of preferred formation of the most stable phenolate, which favored the formation of dendritic units as per the previous findings reported in literature [111,112]. Recently, Khalyavina et al [113] studied the effect of the DB on the T g of hb polyesters and observed that the DB did not show much influence on the T g of the polymers with an identical amount of phenolic -OH groups per unit. For example, the T g and M n values of OH-terminated polymers with DB ¼ 8% (M n ¼ 14,500 Da, T g ¼ 155 C) and DB ¼ 50% (M n ¼ 17,000 g/mol, T g ¼ 152 C), were close to each other.…”

Section: Hyperbranched Poly(aryl Ester)ssupporting

confidence: 56%

Aromatic Hyperbranched Polymers: Synthesis and Application

Ghosh

Banerjee

Voit

2014

Porous Carbons – Hyperbranched Polymers – Polymer Solvation

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Hyperbranched (hb) polymers have been receiving increasing attention because of their unique architecture that results in an interesting set of unusual chemical and physical properties. Over the past decade quite a number of excellent reviews on hb polymers have been published by different research groups, covering various aspects of this class of polymers. This review will highlight the work on aromatic hb polymers of the last decade, emphasizing general synthetic strategies and recent development of alternative synthetic strategies, and discussing various aspects of hb polymers to demonstrate their wide range of applications.

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Section: Hyperbranched Poly(aryl Ester)ssupporting

confidence: 56%

Aromatic Hyperbranched Polymers: Synthesis and Application

Ghosh

Banerjee

Voit

2014

Porous Carbons – Hyperbranched Polymers – Polymer Solvation

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“…Fig. 57 On the other hand, the Zimm branching factor g 0 for h-PMMA decreases from 0.43 to 0.63 in the order of h-PMMA 1 < h-PMMA 2 < h-PMMA 3 , indicating the DB increases as [MMA]/[HEMA] molar ratio decreases. The broad peaks located at 3.90-4.21 ppm attributed to the protons of the ether groups in HEMA units conrm the hyperbranched structures of h-PMMA 1 .…”

Section: Synthesis Of Hyperbranched Pmma Using a Commercially Availabmentioning

confidence: 93%

A versatile strategy for synthesis of hyperbranched polymers with commercially available methacrylate inimer

et al. 2015

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Self-condensing vinyl polymerization (SCVP) provides an efficient approach for synthesis of hyperbranched polymers. However, most of the inimers employed for SCVP need to be synthesized before use. Here, we report a facile strategy to synthesize hyperbranched polymers under mild conditions by using a commercially available hydroxyl-substituted methacrylate as the inimer. The hyperbranched structures of the resulting polymers were confirmed by nuclear magnetic resonance, differential scanning calorimetry and size-exclusion chromatography equipped with online light scattering and viscosity detectors. The synthesis can be performed under mild reaction conditions. Particularly, this approach can be applied to not only the SCVP of vinyl monomers but also the self-condensing ring-opening polymerization of cyclic esters for preparation of hyperbranched polyesters. The present study provides a facile strategy to synthesize hyperbranched polymers.

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“…This indicates that for a very high branch point content up to a perfect dendrimer (DB >> 0.65) the T g might exceed the T g for the perfectly linear analogue, as it has been observed for hyperbranched aromatic polyesters. [29] For another type of hb aromatic polyesters [16] it was also shown that the DB exerts a similar influence on the glass transition temperature. Upon increasing the DB, the course for the silylated, non-interacting polymers linearly decreases by about 10 K, whereas a minimum for the hydroxylated counterpart was observed around a DB of 0.30.…”

Section: Thermorheological Propertiesmentioning

confidence: 94%

“…Although the synthesis and rheological characterization of hyperbranched polymers in general, [12][13][14][15][16][17][18] and specifically of polyglycerol-based structures [19][20][21] have been successfully developed over the last two decades, only few studies focusing on the influence of the branching structure on rheological bulk properties in these complex materials have been reported. [22][23][24] However, detailed structure-property relationships are key for the application of hyperbranched polymers, especially in the areas of functional materials, viscosity modifiers, biomedical applications, and nanotechnology.…”

Section: Introductionmentioning

confidence: 99%

“…A fundamental rheological investigation of hyperbranched aromatic polyesters was carried out by Suneel et al [12] Lederer and co-workers further studied these kind of polymers by developing a remarkable synthetic route to control the degree of branching, [14] also showing the effect of DB on the glass transition (T g ). [16] Furthermore, these systems were investigated with respect to their solution properties. [18] Voit, Serra et al studied the thermomechanical characteristics of hyperbranched polymers as reactive modifier in epoxy thermosets in dependency of the degree of branching.…”

Section: Introductionmentioning

confidence: 99%

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Systematic Variation of the Degree of Branching (DB) of Polyglycerol via Oxyanionic Copolymerization of Glycidol with a Protected Glycidyl Ether and Its Impact on Rheological Properties

Schubert

Schömer

Steube

et al. 2017

Macro Chemistry & Physics

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and a large amount of functional groups with a comparably simple synthesis. The hyperbranched structure of a polymer is characterized by its degree of branching (DB), which can be calculated from the fraction of dendritic (D) and linear (L) units (Equation (1)). [1] = +Control of the branching density of hyperbranched polymers is important both with respect to key properties, such as viscosity, but also with respect to end group functionality. Fundamental work in understanding and quantifying the branching density of hyperbranched polymers was carried out for the AB m -polycondensation approach [1,2] as well as for the self-condensing vinyl polymerization. [3] A review article from 2012 by Higashihara et al. [4] focused on the methodologies to control the DB and summarized recent advances in the synthesis of hyperbranched polymers with a DB of 100% and values between 0% and 100%, mainly by condensation or addition reactions. These methods are based on a concept, in which the rate constants k 1 and k 2 for reaction of the two B-groups of an AB 2 monomer are different. [2] In a theoretical work, it was shown that copolymerizing branching AB m -type monomers with linear AB monomers represents a key strategy to control the degree of branching of hyperbranched polymers. [5] For hyperbranched polyglycerol (hbPG) this translates to the copolymerization of the latent AB 2 monomer glycidol with other epoxides as linear AB comonomers. This has been demonstrated for copolymers of glycidol with ethylene oxide and propylene oxide, leading to hyperbranched materials with glycerol branching points between linear oligo(ethylene glycol) or oligo(propylene glycol) segments. [6,7] In these cases, the DB could be varied between 0.07 and 0.59 with comonomer contents up to 97%. In a recent study, hyperbranched poly(ethylene glycol)-co-(glycerol) copolymers (hbPEGs) have been presented in a broad molecular PolyglycerolsIn an oxyanionic polymerization, glycidol as a latent AB 2 monomer is copolymerized with the protected linear AB glycidyl ether monomer EEGE (ethoxy ethyl glycidyl ether) to generate hyperbranched polyglycerols with an adjustable degree of branching (DB) after deprotection. The DB for the random copolymers is controlled by the comonomer content (10-92% EEGE).

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Effect of the degree of branching on the glass transition temperature of polyesters

Cited by 64 publications

References 17 publications

Aromatic Hyperbranched Polymers: Synthesis and Application

Aromatic Hyperbranched Polymers: Synthesis and Application

A versatile strategy for synthesis of hyperbranched polymers with commercially available methacrylate inimer

Systematic Variation of the Degree of Branching (DB) of Polyglycerol via Oxyanionic Copolymerization of Glycidol with a Protected Glycidyl Ether and Its Impact on Rheological Properties

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