Molar mass analysis of polyamides-11 and -12 by size exclusion chromatography in HFiP

New insights into the structure and composition of technical lignins: a comparative characterisation study

“…HFIP is expensive, but can be recovered and has the major advantage of easily dissolving (bio)polymers at room temperature. [70][71][72][73] Indeed, all six lignins were completely dissolved in HFIP without the need for derivatisation. The molar masses obtained with method E were considerably (1.5-8 times) higher than those recorded with the other methods.…”

Bio-based, amorphous polyamides with tunable thermal properties

“…It is a common observation that polyamides show a different hydrodynamic volume than the used PMMA standards depending on the exact chemical composition, leading to miscalculated (i.e. overestimated) molecular weights compared to M n values derived from NMR and titration techniques [19]. Although 1 H NMR results are prone to error caused by the presence of cyclic polyamide chains and by resolution limitations, they are considered to approach the actual M n more accurately than SEC data.…”

Molecular and macromolecular structure changes in polyamide 11 during thermal oxidation

“…Molar mass of PA11 films was determined by SEC [9,10]. Samples were dissolved in 1,1,1,3,3,3-hexafluoroisopropan-2-ol (HFiP -≥99 % purity -VWR) with a concentration of 1 mg ml -1 .…”

“…The latter technique [9,10] appears to be relevant in comparison with rheometry measurements [4] where part of the oxidized polymer may undergo thermolysis as the measurements are performed in molten state. Furthermore, SEC is expected to be more informative than viscosimetry (only M W [11]) with the aim of quantifying the dual chain scission/crosslinking process in polyamides.…”