Ultrasound assisted polyacrylamide grafting on nano-fibrillated cellulose.

Polyacrylamide has been grafted onto nanofibrillated cellulose (NFC-g-PAM) under mild conditions. This was accomplished by developing and optimizing an ultrasound assisted protocol in the presence of potassium persulfate initiator. The synthesis was optimized on the basis of maximizing grafting percentage and grafting efficiency by varying the initiator and monomer concentration. The data shows that ultrasound has a profound effect in promoting the grafting of PAM onto NFC. The intended grafting was confirmed and the properties of the new co-polymers were examined by elemental analyses, Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Intrinsic viscosity determinations in 0.1M cupriethylenediamine solutions for the NFC-g-PAM copolymers and the starting NFC and PAM homopolymer revealed that grafting of PAM onto nanofibrillated cellulose has a profound effect on the hydrodynamic characteristics of the graft polymers.