Proton exchange membranes with pendent phosphonic acid groups were synthesized by pre-irradiation grafting from vinylbenzyl chloride onto FEP and ETFE films with subsequent Arbuzov phosphonation. Free phosphonic acid groups, which are necessary for proton conductivity, were obtained by acid ester hydrolysis. The phosphonated membranes were characterized by phosphonation degree, FTIR-spectroscopy, ion exchange capacity (IEC), oxidation stability, swelling properties, and thermal properties (TGA).

When agricultural residues are processed to ethanol, lignin and silica are some of the main byproducts. Separation of these two products is difficult and the chemical interactions between lignin and silica are not well described. In the present study, the effect of lignin-silica complexing has been investigated by characterizing lignin and silica coprecipitates by FTIR and solid state NMR. Silica particles were coprecipitated with three different lignins, three lignin model compounds, and two silanes representing silica-inlignin model compounds. Comparison of 29 Si SP/MAS NMR spectra revealed differences in the distribution of silanol hydroxyl groups among different coprecipitates. These differences are dependent on the lignin type. The results are interpreted that the underlying mechanism of the interactions is the formation of hydrogen bonds between lignin aliphatic hydroxyl or carboxyl groups and the silanols, but not a condensation of the silica-inlignin among the silica particles and not the formation of C-O-Si bonds.

No abstract

Summary: Commercial poly(styrene‐co‐acrylonitrile) (SAN) and poly(butadiene‐co‐acrylonitrile) (NBR) were functionalized with oxazoline groups through a reaction with 1,3‐aminoethylpropanediol (AEPD). Each of the two products, along with a third commercial poly(styrene‐co‐vinyl oxazoline) copolymer, went through a reaction with methyl triflate producing stable oxazolinium salts. The products were subsequently used as macroinitiators for the ring‐opening cationic grafting of 2‐methyl and 2‐phenyl oxazoline to produce poly(N‐acylethylenimine) grafts. The products were characterized by FT‐IR, 1H NMR and elemental analysis. The grafted fraction varied from 10 to 55 wt.‐%. The monomer units grafted onto each oxazolinium pendant group varied from 3 to 23 depending on the oxazoline substitution and concentration. The results show, firstly, that controlled and reproducible levels of poly(N‐acylethylenimine) grafts can be incorporated and, secondly, that since these results are general, they are thus applicable to a wide variety of nitrile‐containing polymers.

Summary: Oxazoline functionalities were introduced onto the surface of polyacrylonitrile particles and polyacrylonitrile‐grafted films by the catalyzed reaction of a substituted aminoalcohol with the nitrile groups. The resulting oxazoline group was reacted with methyl triflate to use the resulting oxazolinium salt as initiator for the ring opening grafting of 2‐ethyl‐2‐oxazoline. The products were characterized with Fourier transform infrared spectroscopy (FTIR), elemental analysis, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The modification of polyacrylonitrile with the substituted aminoalcohol achieves high conversions. Conversely, the amount of grafted 2‐ethyl‐2‐oxazoline is low. The results show that controlled levels of 2‐oxazolines or polyoxazolines can be incorporated onto the surface of polyacrylonitrile.