Refractive index increments of polyacrylamide and comments on the light scattering from its solutions

Abstract

The refractive index increments of polyacrylamide for various wavelengths were determined both in the usual solvents (water, ethylene glycol, formamide) and in those so far unused (ethanolamine, dimethyl sulfoxide). The values thus obtained are compared with the reported data. The necessity to employ anhydrous polyacrylamide samples is stressed. The question of the possible effect of ageing of solutions on the refractive index increment values is discussed. No ageing of solutions was observed at room temperature; at elevated temperatures, the amide groups of the polymer undergo hydrolysis in water. 1 wt.-%, and the molar mass determined by light scattering gave M , = 1 , l . lo6 g/mol.Redistilled water was used for differential refractometric measurements; the other solvents (dimethyl sulfoxide, ethanolamine and formamide) were distilled on a laboratory column and their purity was checked by gas chromatography. Commercial ethylene glycol and organic acids (analytical grade) were used without further treatment.

Propensity of Lignin to Associate: Light Scattering Photometry Study with Native Lignins

“…[35][36][37][38] However, we did not find any systematic study that relates the changes of dn/dC to incubation or association phenomena of polymers in solution. During this work, an unexpected finding was obtained regarding the systematic changes in the dn/dC values with the aging of the solution with no supporting literature citations because a unique dn/dC value of lignins in solution was used in all previous work.…”

Molecular weight and the Mark‐Houwink relation for ultra‐high molecular weight charged polyacrylamide determined using automatic batch mode multi‐angle light scattering

“… Mark‐Houwink relation of 30 mol % APAM in 1.0 M NaCl at 30 °C: M ≤ 5.3 × 10 6 g mol −1 , [η] = 1.79 × 10 −4 M 0.723 dL g −1 ; M ≥ 5.3 × 10 6 g mol −1 , [η] = 2.63 × 10 −7 M 1. dL g −1 .…”

“…Light scattering has long been used for MW characterization of PAMs. For several decades, academic and industrial researchers have used light scattering to study the solution behavior and viscosity‐molecular weight relationships of PAM and its derivatives . There are, however, very few published studies on the light scattering analysis of these polymers in the UHMW regions .…”

OMCVD Gold Nanoparticles Covalently Attached to Polystyrene for Biosensing Applications

“…Through the highly reactive amide (NH2) group, the polymer can be chemically modified to produce a positively charged cationic polymer or a negatively charged anionic polymer. It has a refractive index of 1.452 at λ = 546 nm [57]. …”