•Photoinitiators were prepared by Darocur 1173 and cotton cellulose nanowhiskers.•Photolyzed CNW were photo-grafted onto the networks of UV-cured films.•The properties of the UV-cured films were improved.•Dual-functional CNW functioned simultaneously as photoinitiators and additives.Novel dual-functional photoinitiators (DFP) of cotton cellulose nanowhiskers (CNW) were prepared and photo-grafted onto macromolecular networks by photolysis and photopolymerization. DFP were prepared with incorporating a fragmental photoinitiator, 2-hydroxyl-2-methyl-1-phenyl-1-propanone, onto isophorone diisocyanate modified CNW. Characterizations were conducted to verify the feasibility of the synthesis by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, nuclear magnetic resonance spectroscopy, and X-ray powder diffraction, respectively. Thermal stability was investigated by thermogravimetric analysis. The photopolymerization kinetics of DFP in polyurethane acrylate (PUA) oligomers were investigated by real time Fourier transform infrared and UV–vis spectroscopy. Scanning electron microscope was performed to study the fracture surfaces of UV-cured PUA films. The mechanical properties of PUA/DFP films were studied, exhibiting that 5 wt.% DFP significantly reinforced elongation at break of PUA matrix by 80%. It was found that DFP could simultaneously effectively initiate the photopolymerization and photo-graft CNW onto UV-cured PUA networks.Download high-res image (159KB)Download full-size image

12% acrylamide (AM) was grafted onto the surface of nanocellulose whiskers (NCW), which was self-assembled to be the chiral nematic suspension at 3% content. The acrylamide grafted NCW (AM-g-NCW) was characterized with Fourier Transform Infrared Spectroscopy (FTIR). The grafting ratio was measured by elemental analysis. The degrees of crystallinity of the AM-g-NCW were measured by X-ray diffraction (XRD). The liquid crystalline properties of the AM-g-NCW were investigated by the polarizing optical microscopy (POM). The AM-g-NCW was found to self-assembly to be a lyotropic state.