ma401429n_si_001.pdf (511.34 kB)
Online HPLC–NMR: An Efficient Method for the Analysis of PMMA with Respect to Tacticity
journal contribution
posted on 2016-02-18, 17:30 authored by Mathias Hehn, Khumo Maiko, Harald Pasch, Wolf HillerNew methods of liquid adsorption
chromatography were developed to separate poly(methyl methacrylate)
(PMMA) regarding tacticity and molar mass. Gradient and isocratic
chromatographic methods were applied to separate the tactic polymers.
In particular, the online coupling of HPLC–NMR was used to
identify and quantify the microstructural moieties during the chromatographic
separation. It was possible to individually follow the elution of
the syndiotactic, heterotactic as well as isotactic patterns. Several
representative blends of PMMA samples of different tacticities as
well as molar masses were well separated and analyzed. The quantification
of all tacticities of the HPLC–NMR measurements was performed
and the overall compositions were in good agreement with the data
on the bulk samples. In addition, SEC–NMR data of predominantly
isotactic PMMA show dependences of the tacticity on the molar mass.