Characterization of branched polymers by SEC coupled with a multiangle light scattering detector. II. Data processing and interpretation

Podzimek, Štěpán; Vlček, Tomáš

doi:10.1002/app.1871

Cited by 75 publications

(56 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Again, accurate estimations of molar mass distributions of the amphiphilic copolymer dual brushes were complicated by non-size exclusion effects in SEC analysis, as found for the precursor block copolymers. 8,39,40 Nevertheless, for the synthesis of TriB-1, one peak at considerably shorter elution times was observed in the elugrams, corresponding to higher molar mass of the product and indicating successful grafting of BuA to the backbone (Fig. 2a).…”

Section: Synthesis Of Giant Surfactants By ''Grafting-from'' Of Buamentioning

confidence: 99%

Synthesis and self-assembly of amphiphilic semi-brush and dual brush block copolymers in solution and on surfaces

et al. 2011

View full text Add to dashboard Cite

Section: Synthesis Of Giant Surfactants By ''Grafting-from'' Of Buamentioning

confidence: 99%

Synthesis and self-assembly of amphiphilic semi-brush and dual brush block copolymers in solution and on surfaces

et al. 2011

View full text Add to dashboard Cite

“…45 For linear random coils, the gradient values are generally within the 0.5 -0.6 region, whereas for branched polymers the values are typically lower. 46 For these product polymers, the conformation plots (see Figure 8 and ESI Figure S.3) were shown to be non-linear in nature, which is typical for branched polymers, indicating that there are differences in branching within the series. Furthermore, close examination of the data obtained from these R g against M w plots (see Figure 8 and Table 2) strongly indicated that there was a progression in both level of branching compared to linear and relative to branching number achieved as the BOD concentration was increased.…”

Section: Multi-angle Laser Light Scatteringmentioning

confidence: 97%

“…Unfortunately, because it has generally proved impossible to determine DB by either solution or solid state 13 C NMR, average contraction factors parameters such as and ′ , have typically been used in previous literature reports to describe the DB of the branched polymers. 1,[46][47] The mathematical equations that describe these parameters can be found in the ESI (Section S.4). They are calculated based on the mean radius of gyration and intrinsic viscosity of the polymer respectively, where the mean square radius of gyration ‹ 2 › is related to the hydrodynamic volume of a polymer, 44,47 and is measured using light scattering methods.…”

Section: Degree Of Branching (Db) By Gpc-malls and Gpc-viscometermentioning

confidence: 99%

“…DRI detector) to that determined by GPC/MALLS. 46 The explanation for this relationship was that M w (GPC-DRI) is proportional to hydrodynamic volume and M w (GPC-MALLS) is the absolute value. Thus at constant M w , this ratio will be seen to decrease with increasing DB and give a qualitative measure of the relative degree on branching through a range of materials with similar compositions.…”

Section: Degree Of Branching (Db) By Gpc-malls and Gpc-viscometermentioning

confidence: 99%

See 1 more Smart Citation

Facile one-spot synthesis of highly branched polycaprolactone

et al. 2014

View full text Add to dashboard Cite

Reported is the first solvent-free (bulk) synthesis of degradable/bioresorbable, highly branched polymers via tin octanoate Sn(Oct 2 ) catalysed controlled ring opening copolymerisation (ROP) of mono and di-functional lactone monomers that proceed to near quantitative conversion. The successful isolation of solvent soluble, highly branched structures was shown to be dependent on both the concentration of the di-functional monomer and the overall reaction time. Comparison with analogous systems utilising controlled radical polymerisation (CRP) to form the highly/hyper branched polymers suggested significant experimental differences between the two chain growth methods. The maximum proportion of di-functional monomer without gelation ensuing was found to be 0.6 equivalents w.r.t. mono-functional monomer (c.f. 1 with CRP) and the onset of significant levels of branching occurred at approximately 90% conversion (c.f. ~70% with CRP). These differences and significant disparity in reaction times were attributed to (a) the coordination and insertion (C+I) propagation mechanism adopted by the Sn catalyst and (b) the presence of additional trans-esterification reactions at high conversion. Evidence is presented to support the conclusion that there are two mechanisms contributing to the overall branching process in the ROP system at high conversion. First, the C+I mechanism promotes growth of linear polymer until approximately 90% conversion, after which both the C+I and transesterification processes contribute to the interchain branching process. The branched nature of the molecular structures was supported by confirmation plots generated from static light scattering. This data demonstrated that the polymers synthesised exhibit varying degrees of branching, consistent with the di-functional monomer (4, concentration in the feed. The degree of branching was calculated using 3 different methods 2 and the results were shown to be independent of method. Finally, DSC analysis of the polymers demonstrated correlation between the degree of branching achieved and the observed T m for the material where increased branching leads to a drop in the recorded T m .

show abstract

“…[1,[9][10][11][12]21] Unfortunately SEC gives wrong results for polymers with high molar masses or strongly branched polymers. [1,[13][14][15][22][23][24][25][26][27][28][29][30][31][32][33][34] In 1966 the field-flow fractionation (FFF) technique was developed. [35] In this system the separation is based on an external separation field.…”

Section: Introductionmentioning

confidence: 99%

Visualization of Thermo‐Oxidative Degradation of Polyolefins in Solution Using HT‐SEC and HT‐AF4‐MALS

Otte

Pasch

Brüll³

et al. 2011

Macro Chemistry & Physics

View full text Add to dashboard Cite

The molar mass distributions of high‐molar‐mass PE and PP were characterized using HT‐AF4 and HT‐SEC in combination with IR and MALS detection. Calculated molar mass distributions, average molar masses and radii of gyration were compared. It was found that HT‐AF4 can detect the real extent of thermo‐oxidative degradation during dissolution. HT‐SEC is affected by shear and thermo‐oxidative degradation while in HT‐AF4 no shear stress exists. As a consequence, the molar mass averages obtained from HT‐SEC are pronouncedly lower as obtained from HT‐AF4. In addition, branched polyolefins cannot be correctly characterized by SEC‐MALS due to abnormal co‐elution effects. HT‐AF4 is therefore the method of choice for studying the thermo‐oxidative degradation of macromolecules with high molar masses. magnified image

show abstract

Characterization of branched polymers by SEC coupled with a multiangle light scattering detector. II. Data processing and interpretation

Cited by 75 publications

References 25 publications

Synthesis and self-assembly of amphiphilic semi-brush and dual brush block copolymers in solution and on surfaces

Synthesis and self-assembly of amphiphilic semi-brush and dual brush block copolymers in solution and on surfaces

Facile one-spot synthesis of highly branched polycaprolactone

Visualization of Thermo‐Oxidative Degradation of Polyolefins in Solution Using HT‐SEC and HT‐AF4‐MALS

Contact Info

Product

Resources

About