[Mitch]

I mafe a 10kdalton polyethylenamine derivative polymer and have no idea how to characterize it? Its a very viscous polymer and aside from IR I don't know what other method could be used to characterize it.

[movies]

That won't fly on any mass spec?  MALDI-TOF?  You could get NMR, maybe.  Also HPLC might be interesting to get an idea of purity.  What about measuring the PDI?

[DrCMS]

GPC is the first thing i'd do it'll give you info on molecular weight and polydispersity.

[HP]

For viscosity mesurement you may use Bruckfield viscosity meter which will give you idea for dynamic viscosity of your polymer in solutions with diferent concentrations. Light scatering  and dynamic one may help you for some specific phenomena measurment e.g agregation and micell forming properties at different solvents or polymer complexation. DSC and TGA mesurments will help you determine Tg(glass temperature) and some H and S data. Raman spectroscopy can help you determine the conformation changes with your polymer in solution. Also there's two kind of polyethylene imine - linear with only primary NH2 groups(obtained by polymerisation and further decarboxylation of Lewis anhydrides) and branched with 1',2' and 3' N-atoms (obtained by ring opening polymerization ethylene imine - aziridine).