Modeling the Rheology of Concentrated AB/AB<sub>2</sub> Hyperbranched Polymeric Systems

Lee, A. T.; McHugh, A. J.

doi:10.1021/ma011430s

Cited by 9 publications

(7 citation statements)

References 16 publications

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“…[29][30][31][32][33][34][35][36][37][38][39][40][41] However, few AB and AB 2 monomers are available commercially due to tedious synthetic approaches for asymmetric functionality. Moreover, the statistical distribution of segments results in broad compositional distributions, and the concept of average segment length does not accurately describe the structures.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the statistical distribution of segments results in broad compositional distributions, and the concept of average segment length does not accurately describe the structures. [36][37][38] As a result, the development of facile alternative approaches for the preparation of highly branched polymers with acceptable mechanical properties based on readily available monomers will promote significant progress in this field.…”

Section: Introductionmentioning

confidence: 99%

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Highly Branched Poly(arylene ether)s via Oligomeric A₂ + B₃ Strategies

Qin¹,

Ünal

Fornof

et al. 2006

Macro Chemistry & Physics

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Summary: Branched poly(arylene ether)s were prepared in an oligomeric A2 + B3 polymerization of phenol endcapped telechelic poly(arylene ether sulfone) oligomers as A2 and TFPPO as trifunctional monomer B3. The molar mass of the A2 oligomer significantly influenced the onset of gelation and the DB. A high level of cyclization during polymerization of low molar mass A2 oligomers (U3 = 660 and U6 = 1 200 g · mol−1) led to a high conversion of functional groups in the absence of gelation, and the level of cyclization reactions in the polymerization decreased as the molar mass of the A2 oligomer was increased. The pronounced steric effect in the polymerization of higher molar mass A2 oligomers (U8 = 1 800 and U16 = 3 400 g · mol−1) resulted in low reactivity of the third aryl fluoride in the B3 monomer. As a result, only slightly branched (U8 = 1 800 g · mol−1) or nearly linear (U16 = 3 400 g · mol−1) high molar mass products were obtained with higher molar mass A2 oligomers. The branched polymers exhibited lower Mark‐Houwink exponents and [η] relative to linear analogs, and differences between the branched polymers and linear analogs were less significant as the molar mass of the A2 oligomers was increased due to a decrease in the overall DB. magnified image

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Highly Branched Poly(arylene ether)s via Oligomeric A₂ + B₃ Strategies

Qin¹,

Ünal

Fornof

et al. 2006

Macro Chemistry & Physics

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“…Branched polymers have attracted increasing attentions in recent years . They can greatly vary the rheology behavior of linear polymers after blending .…”

Section: Introductionmentioning

confidence: 99%

Improved processibility of silicone composites by MQ silicone resins

Huihui

Zhang³

et al. 2018

J of Applied Polymer Sci

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Processibilities of silicone composites were always a problem for their high content of SiO2 powders. This article found that the substitution of silicone resins for linear polydimethylsiloxanes (PDMS) made processibilities easier. Three silicone resins (MQ1.0, MQ1.1, and MQ1.2) with clarified chemical structures (by FT IR, 29Si NMR, and GPC) were adopted. Their shearing viscosities [η(trueγ̇)] were greatly higher than PDMS with higher molecular weight, which could be assigned to stronger molecular interactions as surface tension and flowing activation energy ΔE indicated. On the contrary, η(trueγ̇) of MQ‐PDMS binary blends greatly decreased to that even lower than either components (about 85% utmost decrease comparing to PDMS), for the variation of molecular interaction rather than dilution effect. Furtherly, when PDMS were partly replaced with MQ resins, process time of PDMS–SiO2 silicone composites were greatly shortened (from >6 to 2 h), while with better SiO2 dispersion (Mooney viscosity greatly decreased from 30.0 to 5.0 MU). Better dispersion of SiO2 fillers in composites could be confirmed by SEM and mechanical properties. For the better dispersion, mechanical properties of composites were improved with higher elastic modulus, higher tensile strength, and higher hardness, especially with higher elongation at break (utmost increased from 190% to 277%). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46445.

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“…To this end, various researchers have studied a "zoo" of various lowpolydispersity model long-chain branched polymers, with topologies ranging from star 3−8 to "H" 9 to "comb" 10−13 and hyperbranched (or branch-on-branch) topologies. 14 The rheology of such long-chain branched polymers is extremely sensitive to branch length and branch polydispersity as well as to topology. In fact, failure to predict accurately the rheology of such materials might sometimes be the result of imperfections in the synthesis of these polymers, which are never completely monodisperse nor completely free of contaminating polymers, such as unreacted branches, or complex multiply branched side products.…”

Section: Introductionmentioning

confidence: 99%

“…To pursue either of these goals, the ability must be developed to predict the rheology of branched polymers with different levels and types of branching. To this end, various researchers have studied a “zoo” of various low-polydispersity model long-chain branched polymers, with topologies ranging from star − to “H” to “comb” − and hyperbranched (or branch-on-branch) topologies . The rheology of such long-chain branched polymers is extremely sensitive to branch length and branch polydispersity as well as to topology.…”

Section: Introductionmentioning

confidence: 99%

Analytical Rheology of Asymmetric H-Shaped Model Polybutadiene Melts

et al. 2012

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An asymmetric H-shaped model polybutadiene (PBd) melt, H(SS13LL20)B58, with a backbone of molar mass 58 kg/mol and with two short arms of molar mass 13 kg/mol and two long arms with molar masses around 20 kg/mol, was designed and synthesized by anionic polymerization and purified by fractional precipitation. To obtain this novel structure, two short arms were synthesized and linked together using 4-(dichloromethylsilyl)diphenylethylene (DCMSDPE). The backbone was then grown from this linkage point to produce an asymmetric star intermediate terminating in a reactive anion at the end of the backbone. The two long arms were similarly grown in a separate reaction vessel and then linked by DCMSDPE, and these linked long arms were then attached to the backbone of the asymmetric star. The multiple steps of this reaction scheme led to multiple possible byproducts. The most likely of these were identified and quantified by temperature gradient interaction chromatography (TGIC) performed on both purified and unpurified H(SS13LL20)B58 product and its asymmetric star-shaped synthetic precursor. We then performed linear rheological studies on purified and unpurified H(SS13LL20)B58, its star precursor, and blends of the purified H polymer with its star precursor and found that their rheological behaviors can be predicted reasonably accurately by the “hierarchical model” [Wang et al. (2010)], if the impurities identified by TGIC are accounted for in the rheological modeling. These results show that TGIC characterization of product and intermediate reaction products, supplemented by rheological studies of controlled blends, are important steps in determining the accuracy of rheological models of polymers with complex branching architectures.

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Modeling the Rheology of Concentrated AB/AB₂ Hyperbranched Polymeric Systems

Cited by 9 publications

References 16 publications

Highly Branched Poly(arylene ether)s via Oligomeric A₂ + B₃ Strategies

Highly Branched Poly(arylene ether)s via Oligomeric A₂ + B₃ Strategies

Improved processibility of silicone composites by MQ silicone resins

Analytical Rheology of Asymmetric H-Shaped Model Polybutadiene Melts

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Modeling the Rheology of Concentrated AB/AB2 Hyperbranched Polymeric Systems

Cited by 9 publications

References 16 publications

Highly Branched Poly(arylene ether)s via Oligomeric A2 + B3 Strategies

Highly Branched Poly(arylene ether)s via Oligomeric A2 + B3 Strategies

Improved processibility of silicone composites by MQ silicone resins

Analytical Rheology of Asymmetric H-Shaped Model Polybutadiene Melts

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Product

Resources

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Modeling the Rheology of Concentrated AB/AB₂ Hyperbranched Polymeric Systems

Highly Branched Poly(arylene ether)s via Oligomeric A₂ + B₃ Strategies

Highly Branched Poly(arylene ether)s via Oligomeric A₂ + B₃ Strategies