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

Qian, Yong; Deng, Yonghong; Guo, Yunqing; Yi, Conghua; Qiu, Xueqing

doi:10.1515/hf-2012-0063

Cited by 15 publications

(17 citation statements)

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“…The refractive index increment (dn/dc) value of NaLS (1.80, see Qian et al 2013) was determined by BI-DNDC (DNDC-2010, WEG, Kerpen, Germany). A 632.8 nm interference filter and a Glan-Thompson interferometer were used to avoid overestimation of the molecular weight Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 5/25/15 4:58 PM of NaLS due to fluorescence and polarization.…”

Section: Characterizationmentioning

confidence: 99%

“…The NaLS solution is diluted to an extent that the adsorption effect could be neglected. For theoretical details, see Qian et al (2013). For dust removal, all the solutions were filtered by 0.45 μm polyvinylidene fluoride (PVDF) Millipore Millex-LCR filters before the LS experiments.…”

Section: Characterizationmentioning

confidence: 99%

“…At higher concentrations, the apparent M w can be made visible by different methods Yan et al 2010). Generally, during DLS measurement the fmD and smD are perceptible in the NaLS solutions due to the aggregation and polyelectrolyte effects Qian et al 2013). The former refers to the diffusion of NaLS monomolecules, whereas the latter is related to the combination of aggregation and polyelectrolyte effect.…”

Section: Preparation Of Nals Monomolecular Solutionmentioning

confidence: 99%

“…The former refers to the diffusion of NaLS monomolecules, whereas the latter is related to the combination of aggregation and polyelectrolyte effect. The polyelectrolyte effect is inhibited by adding NaCl (Qian et al 2013) and the NaLS aggregates can be removed by filtering the high-salt solution with a filter of a proper pore size. Figure 1a shows the size distributions of 0.6 g·l -1 NaLS which is dissolved in 1.2 mol·l -1 NaCl solution and then treated by different methods, and the corresponding M w determined by SLS are summarized in Table 1.…”

Section: Preparation Of Nals Monomolecular Solutionmentioning

confidence: 99%

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Aggregation of sodium lignosulfonate above a critical temperature

Qian¹,

Deng²,

Qiu³

et al. 2014

Holzforschung

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Single molecules of sodium lignosulfonate (NaLS) were prepared and their aggregation behavior was studied as a function of temperature. The molecular dispersity of the NaLS solutions were confirmed by dynamic light scattering (DLS), and the aggregation behavior was studied by DLS and static light scattering (SLS), fluorescence spectrometry (FS), and atomic force microscopy (AFM). It was demonstrated that NaLS molecules started to aggregate above a critical temperature and the aggregation behavior was related to their spherical microgel conformation and hydrophobic interaction. During the DLS measurement, when NaLS was dissolved in 1.2 mol·l -1 NaCl aqueous solution and then filtered with 0.45 μm syringe filter, the slowmode diffusion (smD) corresponded to the polyelectrolyte effect and the original aggregates disappeared and the fast-mode diffusion (fmD) corresponded to the monomolecular NaLS (not yet aggregated) in the solution. When the temperature of the NaLS solution was raised to 38°C, the disappeared smD in DLS analysis appeared again, indicating that NaLS molecules started to form new aggregates. Due to the aggregation at 38°C, molecular weight (M w ) obtained from the SLS had a sharp increase, intensity ratio (I 1 /I 3 ) of pyrene in FS suddenly decreased, and the adsorption of NaLS on a solid substrate and the corresponding roughness of the surface increased significantly.

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Section: Characterizationmentioning

confidence: 99%

Section: Characterizationmentioning

confidence: 99%

Section: Preparation Of Nals Monomolecular Solutionmentioning

confidence: 99%

Section: Preparation Of Nals Monomolecular Solutionmentioning

confidence: 99%

See 2 more Smart Citations

Aggregation of sodium lignosulfonate above a critical temperature

Qian¹,

Deng²,

Qiu³

et al. 2014

Holzforschung

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“…NaLS was found to form aggregates with different size distributions in diluted aqueous solution when its concentration exceeded the critical aggregation concentration (CAC) Yan et al 2010 ;Qian et al 2012 ;Zhou et al 2012 ). The aggregation is also affected by the pH and ionic strength of the solution.…”

Section: Introductionmentioning

confidence: 99%

Aggregation and adsorption behaviors of carboxymethylated lignin (CML) in aqueous solution

Gan¹,

Zhou²,

Yang³

et al. 2012

Holzforschung

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Carboxymethylated lignin (CML) as a watersoluble lignin derivative is a multipurpose adsorbent and dispersant. In this article, the aggregation and adsorption behaviors of CML have been investigated in aqueous solution using fluorescence spectroscopy, dynamic light scattering, and a quartz crystal microbalance combined with dissipation monitoring techniques. It was found that CML forms aggregates when its concentration exceeds the critical aggregation concentration (CAC). The CAC of CML1 with a carboxylic (COOH) group content of 2.8 mmol g -1 was 0.022 g l -1 , and that of CML2 with a COOH group content of 2.0 mmol g -1 was 0.026 g l -1 . The adsorption behavior of CML on the gold surface was strongly dependent on the pH and ionic strength of the solution. At low pH and ionic strength, more CMLs were adsorbed at the gold/water interface, and the layers were rigid. The results could be used not only from the theoretical but also from the application point of view.

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Getting Closer to Absolute Molar Masses of Technical Lignins

et al. 2018

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Determination of molecular weight parameters of native and, in particular, technical lignins are based on size exclusion chromatography (SEC) approaches. However, no matter which approach is used, either conventional SEC with a refractive index detector and calibration with standards or multi‐angle light scattering (MALS) detection at 488 nm, 633 nm, 658 nm, or 690 nm, all variants can be severely erroneous. The lack of calibration standards with high structural similarity to lignin impairs the quality of the molar masses determined by conventional SEC, and the typical fluorescence of (technical) lignins renders the corresponding MALS data rather questionable. Application of MALS detection at 785 nm by using an infrared laser largely overcomes those problems and allows for a reliable and reproducible determination of the molar mass distributions of all types of lignins, which has been demonstrated in this study for various and structurally different analytes, such as kraft lignins, milled‐wood lignin, lignosulfonates, and biorefinery lignins. The topics of calibration, lignin fluorescence, and lignin UV absorption in connection with MALS detection are critically discussed in detail, and a reliable protocol is presented. Correction factors based on MALS measurements have been determined for commercially available calibration standards, such as pullulan and polystyrene sulfonate, so that now more reliable mass data can be obtained also if no MALS system is available and these conventional calibration standards have to be resorted to.

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

Cited by 15 publications

References 0 publications

Aggregation of sodium lignosulfonate above a critical temperature

Aggregation of sodium lignosulfonate above a critical temperature

Aggregation and adsorption behaviors of carboxymethylated lignin (CML) in aqueous solution

Getting Closer to Absolute Molar Masses of Technical Lignins

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