Effect of molecular weight on the refractive increment of polyethylene and n‐alkanes

Abstract

synopsisAs in the case with other polymers previously reported, the values of the refractive index increment dn/dc of polyethylene and the n-alkanes change with molecular weight. Most of the variation may be understood by examination of the role of density in the Lorentz-Lorenz mixing equation ior specific refractivity, R12 = plR1 + P2R2 used to calculate dnldc. It rcay also be shown that as the absolute refractive index difference between solute and solvent becomes smaller, dnldc becomes more sensitive to density change of the solute.

Molecular weight dependency of refractive index increment of polystyrene determined by uniform oligomers

“…Molecular weight dependencies of dn / dc were reported experimentally, which are expressed as linear functions of reciprocal number‐average molecular weight 5–10. However, it should be verified that the molecular weight dependency is also expressed as a linear function of reciprocal molecular weight of each component (see the ).…”

“…On the other hand, in the oligomeric region, a number of studies have shown that dn / dc greatly depends on the molecular weight 1–10. Variations in dn / dc affect not only the accuracy of M w measured by SLS, but also that of molecular weight distribution measured by size‐exclusion chromatography (SEC).…”

The characterization of linear polyethylene SRM's 1482, 1483, and 1484. III. Weight-average molecular weights by light scattering

“…Ao is the wavelength in vacuum of the scallered light, set at 546 nm in this work , nand nB are the indices of refra ction of the solvent and benzene, taken as 1.586 [8] and 1.503 [3], respectivel y, dn/dc is the differential refractive index of the solution, measured as described in 3.1, N A is Avogadro's number, taken as 6.022 X 10 23 mol -I, Vv B is the Rayleigh ratio for the vertically polarized scattering of vertically polarized light from benzene, used for calibration and obtained as described in the following paragraph, and S is the measured ratio I G/I B of the scattering signal obtained from the glass working standard to that obtained from benzene.…”

Dendrimeric Alkylated Polyethylenimine Nano-carriers with Acid-Cleavable Outer Cationic Shells Mediate Improved Transfection Efficiency Without Increasing Toxicity

“…The UV detector, Wyatt Dawn EOS, and refractive index detector were aligned using an injection of 0.50 mg bovine serum albumin monomer fractionated by a Superdex 200 10/300 GL gel permeation column. Alkylated bPEI and 1,4-bis-maleimidobutane-containing dendrimer constructs were analyzed using three PSS Novema columns in series: a guard column, a 300 Å 8×300 mm column, and a 1,000 Å 8×300 mm column (38). All samples were dissolved in 1% aqueous formic acid filtered through a 0.2 μm pore size filter and eluted with the same solvent.…”

“…To allow mass measurements, the Altex 156 refractive index detector was calibrated using five sodium chloride concentrations known to the fourth significant digit (e.g., 0.1847 mg/mL) spanning the range of 0.0000-2.000 mg/mL (NaCl specific refractive index increment, dn/dc=0.172 mL/g) (38). The Wyatt Dawn EOS 18-angle detectors were normalized using spectrophotometric grade toluene.…”