Synthesis and characterisation of star branched polyesters with dendritic cores and the effect of structural variations on zero shear rate viscosity

Claesson, Hans; Malmström, Eva; Johansson, Mats; Hult, Anders

doi:10.1016/s0032-3861(02)00073-3

Cited by 100 publications

(65 citation statements)

References 19 publications

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“…[1][2][3][4][5][6] Long chain branching alters both the shear-rate dependence [7][8][9][10] and the strain dependence [11][12][13] of the rheological response, as well as enhancing strainhardening in extensional flow. [14][15][16][17] On the other hand, a multiplicity of short branches can yield high molecular weight polymers having very low melt viscosities, 18,19 albeit at the expense of some cured properties. 20 Polyisobutylene (PIB) is one of the more interesting rubbers.…”

Section: Introductionmentioning

confidence: 99%

Filler Dispersion in Hyperbranched Polyisobutylene

Roland

Robertson

Nikiel³

et al. 2004

Rubber Chemistry and Technology

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The microdispersion of carbon black filler in linear and hyperbranched polyisobutylene (PIB) was assessed from dynamic mechanical and volume resistivity measurements. While no significant differences were observed in the carbon black concentration necessary for formation of a filler network, in comparison to the linear polymer, the highly branched PIB was found to have substantially more carbon black agglomeration. This occurs despite its higher viscosity, due to the relative inaccessibility of large portions of the molecule, as a result of the profuse treelike branching. The consequence is more extensive interaggregate interaction, and thus a larger Payne effect and greater mechanical hysteresis.

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Section: Introductionmentioning

confidence: 99%

Filler Dispersion in Hyperbranched Polyisobutylene

Roland

Robertson

Nikiel³

et al. 2004

Rubber Chemistry and Technology

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“…The degree of polymerization of the arms (DP p ) was calculated from the triplet at 3.65 ppm (e), which corresponds to the methyl group adjacent to the hydroxyl end group, and the triplet at 4.05 ppm (d), which corresponds to the methyl groups adjacent to the ester linkages. [57] The signal of the H40 core was not visible in any of the 1 H NMR spectra because of the large excess of PCL.…”

Section: Synthesis and Characterization Of H40-(pcl) Pmentioning

confidence: 97%

“…However, the relative size of the NMR peak from the methyl group adjacent to the hydroxyl group decreased with increasing DP n , resulting in reduced accuracy at high M n . [57] The Mark-HouwinkSakurada coefficient decreased to close to zero ( Table 2), indicating that the polymers behave as compact spheres in solution.…”

Section: Synthesis and Characterization Of H40-(pcl) Pmentioning

confidence: 98%

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Amphiphilic Multi‐Arm Star‐Block Copolymers for Encapsulation of Fragrance Molecules

Ternat

Kreutzer

Plummer

et al. 2007

Macro Chemistry & Physics

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Novel amphiphilic multi‐arm star‐block copolymers with a hyperbranched core, a hydrophobic inner shell, and a hydrophilic outer shell have been prepared from a commercial hyperbranched polyester macroinitiator by ring‐opening polymerization of ε‐caprolactone, followed by atom transfer radical polymerization of tert‐butyl acrylate (tBuA). Hydrolysis of the tert‐butyl groups was then used to convert the poly(tBuA) blocks to poly(acrylic acid), resulting in stable amphiphilic core‐shell structures with significantly higher degrees of functionality than reported so far in the literature. A strong correlation between the maximum concentration of selected hydrophobic guest molecules and the concentration of amphiphilic star‐block copolymer in aqueous solution was observed by 1H NMR, demonstrating the capacity of these copolymers to encapsulate and disperse significant loadings (up to about 27 wt.‐%) of volatile hydrophobic molecules such as fragrances in water.magnified image

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“…[1][2][3][4][5][6][7][8][9][10][11] In the dynamically growing area of biocompatible and biodegradable polymers, the synthesis and characterization of starshaped aliphatic polyesters are particularly advanced. [12][13][14][15][16][17][18][19][20][21][22][23][24] Among others, some of our recent articles [25][26][27][28][29][30] report the synthesis and characterization of 1-, 2-, 3-, 4-, 5-, 6-, 8, 13-, and 32-arm star-shaped poly(L-lactide)s by size exclusion chromatography (SEC), liquid chromatography under critical conditions (LC-CC), two-dimensional LC-CC/SEC, NMR, and fluorescence spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

One‐pot synthesis of star‐shaped aliphatic polyesters with hyperbranched cores and their characterization with size exclusion chromatography

Biela

Polanczyk

2006

J. Polym. Sci. A Polym. Chem.

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Star‐shaped aliphatic polyesters with hyperbranched cores were prepared by a two‐step synthesis with the one‐pot, arms‐first core method. First, the polymerization of ε‐caprolactone (CL) or L,L‐lactide (LA) was initiated with aluminum isopropoxide trimer. Then, the resulting poly(CL)–OAl< or poly(LA)–OAl< living chains were employed as initiators for 5,5′‐bis(oxepan‐2‐one) or 1,6‐dioxaspiro[4,4]nonane‐2,7‐dione) polymerization. A sequence of chain growth and branching reactions led to the formation of starlike macromolecules. The progress of the polymerization was followed with size exclusion chromatography, and the products of the model reaction were also analyzed with matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry.

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Synthesis and characterisation of star branched polyesters with dendritic cores and the effect of structural variations on zero shear rate viscosity

Cited by 100 publications

References 19 publications

Filler Dispersion in Hyperbranched Polyisobutylene

Filler Dispersion in Hyperbranched Polyisobutylene

Amphiphilic Multi‐Arm Star‐Block Copolymers for Encapsulation of Fragrance Molecules

One‐pot synthesis of star‐shaped aliphatic polyesters with hyperbranched cores and their characterization with size exclusion chromatography

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