Branching analysis of star-shaped polybutadienes by temperature gradient interaction chromatography-triple detection

Lee, Hyojoon; Yang, Jum-Hong; Chang, Taihyun

doi:10.1016/j.polymer.2017.01.070

Cited by 18 publications

(14 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous works on comb shaped polymers show that g exp is larger than g rw in both good solvents and theta solvents . Similar behavior was also found for the star‐shaped polymers . It indicates that the random walk statistics does not reflect the actual chain conformation of the branched polymers at a theta condition.…”

Section: Resultssupporting

confidence: 59%

“…Therefore, the synthesis of model comb‐shaped polymers is more difficult than star‐shaped polymers and the model comb‐shaped polymers usually have multivariate distribution in the number of branches and the location of the branch points even if it is made with a nearly uniform backbone as well as branch chains prepared by anionic polymerization. For well‐defined star‐shaped polybutadienes, we recently reported that ε = 0.7 in a good solvent while ε = 0.6 in a theta solvent in the relationship of g ′ = g rw ε where the subscript rw means that the geometric contraction factor is calculated by the random walk statistics …”

Section: Introductionmentioning

confidence: 99%

“…Utilizing the high MW resolution of temperature gradient interaction chromatography (TGIC), the local MW dispersity issue in SEC separation is resolved to a large extent . In addition, the TGIC solvent is often a theta solvent for the polymer analytes and TD analysis at the theta condition can be realized in TGIC‐TD analysis …”

Section: Introductionmentioning

confidence: 99%

“…For well-defined starshaped polybutadienes, we recently reported that ε = 0.7 in a good solvent while ε = 0.6 in a theta solvent in the relationship of g′ = g rw ε where the subscript rw means that the geometric contraction factor is calculated by the random walk statistics. [11] In early times, R g and/or [η] for model comb-shaped polymers of well-defined chain structure were compared with the linear polymers. [12][13][14][15][16][17][18][19] The experimental results showed a general behavior according to Equation (3), but failed to reach a consensus in the value of the exponent ε.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Branching Analysis of Comb‐Shaped Polystyrene with Long Chain Branches

Lee

Chang

2017

Macro Chemistry & Physics

Self Cite

View full text Add to dashboard Cite

Model comb-shaped polystyrene (PS) samples are synthesized by anionic polymerization and the as-prepared PS heterogeneous combs are further fractionated by temperature gradient interaction chromatography (TGIC) to obtain well-defined random combs with 1-4 branches at random positions on a backbone. Size exclusion chromatography-triple detection and TGICtriple detection analyses are carried out with the fractionated PS random combs in a good and a theta solvent, respectively. The experimentally observed geometric contraction factor (g), the ratio of the mean square radius of gyration and the hydrodynamic contraction factor (g′), and the ratio of the intrinsic viscosity are compared. It is observed that the two contraction factors follow the relationship of g′ = g ε reasonably well and the exponent ε of the PS combs is found as ∼1 in a good solvent and ∼0.66 in a theta solvent. Furthermore, it is found that the theoretical g rw is not in good agreement with the experimental results.

show abstract

Section: Resultssupporting

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Branching Analysis of Comb‐Shaped Polystyrene with Long Chain Branches

Lee

Chang

2017

Macro Chemistry & Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, at present it is not straightforward to determine the number k of branch points in a polymer molecule experimentally. On the other hand, the g ‐ratio could be measured accurately as a function of molecular weight, or the degree of polymerization, nearly independent of polymer architecture 17,18. The expected Rg 2 for a given degree of polymerization

\overset{true¯}{R g^{2}} (r)

, as shown in Figure 2, could be determined experimentally.…”

Section: Resultsmentioning

confidence: 98%

Random Branching of Polymer Chains with Schulz–Zimm Distribution. 2. Radius of Gyration and Maximum Span Length

Tobita

2020

Macro Theory & Simulations

View full text Add to dashboard Cite

Mean‐square radius of gyration Rg2 and the maximum span length LMS of each polymer molecule are investigated for the random branching of primary chains that follow the Schulz–Zimm distribution, by using the Monte Carlo simulation method. It is found that the expected g‐ratio of Rg2 of the branched molecule to that of a linear molecule for a given number of branch points k does not change with the branching density. The expected g‐ratio becomes larger for the primary chains with broader distribution. An approximate formula for the relationship between g‐ratio and k that accounts for the distribution breadth is proposed. The relationship between the weight fraction of the maximum span chain LMS/(degree of polymerization) and k shows the analogous behavior with that for g‐ratio and k. The magnitude of Rg2 is proportional to LMS, with Rg2 = 0.18 LMS, irrespective of the breadth of the primary polymer chain length distribution.

show abstract

Cost‐efficient modeling of distributed molar mass and topological variations in graft copolymer synthesis by upgrading the method of moments

Figueira

Edeleva

et al. 2022

AIChE Journal

View full text Add to dashboard Cite

Cost‐efficient deterministic method of moments solvers, as widely used to calculate average characteristics of chemical processes driven by population variations (e.g., average chain lengths), can be a posteriori extended with approximated solutions delivering distributed properties (e.g., chain length distributions). However, these solutions are rarely verified, specifically for complex systems with many population members and strong coupling, as is the case for industrially relevant free‐radical‐induced grafting (FRIG) toward graft copolymer (GC) synthesis with monomer unit dependent reactions. FRIG, as studied in the present work with polybutadiene at low styrene conversions, is an important chemical process, for example, the production of compatibilizers and high‐impact materials. Deterministic model validation is uniquely performed by benchmarking the low to medium molar mass (MM) results (29 topologies) in the log‐molar mass distribution with detailed matrix‐based kinetic Monte Carlo simulation output, inherently capable of mapping distributions. The GC product is identified to be a heterogeneous mixture in MM, chemical composition, and molecular topology at any styrene conversion. The molecular structural evolution during GC synthesis is further theoretically related to both one‐dimensional size‐exclusion chromatography (1D‐SEC) and two‐dimensional liquid chromatography (2D‐LC) analysis. It is shown that conventional SEC—even in the absence of broadening—is insufficient for GC separation, mainly due to the unavoidable coelution of topologically different GC species. In any case, the parallel running of advanced modeling tools allows for detailed molecular interpretation.

show abstract

Branching analysis of star-shaped polybutadienes by temperature gradient interaction chromatography-triple detection

Cited by 18 publications

References 29 publications

Branching Analysis of Comb‐Shaped Polystyrene with Long Chain Branches

Branching Analysis of Comb‐Shaped Polystyrene with Long Chain Branches

Random Branching of Polymer Chains with Schulz–Zimm Distribution. 2. Radius of Gyration and Maximum Span Length

Cost‐efficient modeling of distributed molar mass and topological variations in graft copolymer synthesis by upgrading the method of moments

Contact Info

Product

Resources

About