Determination of the molecular weight and compositional heterogeneity of block copolymers using combined gel permeation chromatography and low-angle laser light scattering

Polymer ◽  
1986 ◽  
Vol 27 (8) ◽  
pp. 1170-1176 ◽  
Author(s):  
T. Dumelow ◽  
S.R. Holding ◽  
L.J. Maisey ◽  
J.V. Dawkins
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Block Copolymers ◽  
Laser Light ◽  
Gel Permeation Chromatography ◽  
Laser Light Scattering ◽  
Compositional Heterogeneity ◽  
Gel Permeation

The effect of heterogeneity in composition on the determination of molecular weight distribution of block copolymers by gel permeation chromatography

1969 ◽  
Vol 22 (3) ◽  
pp. 543 ◽  
Author(s):  
JR Urwin ◽  
DN Cramond
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Block Copolymers ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Gel Permeation Chromatography ◽  
Scattering Data ◽  
Gel Permeation

The molecular weight of samples of block copolymers of poly(isoprene : styrene) determined by gel permeation chromatography (g.p.c.) are found to deviate from the values obtained by light scattering and osmometry. The extent of the deviation depends on composition, and comparision of (g.p.c.) values with osmometry (MN) can be interpreted if account is taken of the effect of heterogeneity. The drift in composition with molecular weight calculated from light scattering data can be used to predict the direction of the deviation, at least qualitatively.

Determination of absolute molecular weight of sodium lignosulfonates (NaLS) by laser light scattering (LLS)

Holzforschung ◽  
2013 ◽  
Vol 67 (3) ◽  
pp. 265-271 ◽  
Author(s):  
Yong Qian ◽  
Yonghong Deng ◽  
Yunqing Guo ◽  
Conghua Yi ◽  
Xueqing Qiu
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Laser Light ◽  
Gel Permeation Chromatography ◽  
Laser Light Scattering ◽  
Sodium Polystyrene Sulfonate ◽  
Sodium Lignosulfonate ◽  
The Absolute ◽  
Syringe Filter

Abstract The problems related to the determination of the absolute molecular weight (Mw) of sodium lignosulfonate (NaLS) are the focus of the present work. Four narrow-dispersed NaLS fractions were collected by filtration, ultrafiltration, and gel permeation chromatography (GPC), and their Mw measured by laser light scattering (LLSMw) was compared with that obtained by GPC (GPCMw). The LLSMw values were much larger than GPCMw, and this Mw difference increased with increasing Mw of NaLS. This finding confirms the known polyelectrolyte and aggregation effects of NaLS. The deviation is also partly due to the conformation differences between the GPC standard (sodium polystyrene sulfonate) and the NaLS molecules. The effects of polyelectrolytes and NaLS aggregates could be inhibited by adding enough NaCl salt in the NaLS solution and filtering the NaLS/NaCl solution through a syringe filter. As a result, the slow mode in dynamic LLS measurement disappeared. By this approach, the absolute LLSMw values were only slightly larger than that determined by GPC due to the conformation differences between the GPC standard and the NaLS molecules.

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