The chemo-rheological behavior of an acrylic based UV-curable inkjet ink: Effect of surface chemistry for hyperbranched polymers

•Modification of hyperbranched polymers.•Inkjet challenges with UV-curable inks.•UV-curable inkjet ink formulations.•The effect of hyperbranched polymers on chemo-rheological behavior of UV-curable inkjet inks. A polyester-amid based hyperbranched polymer (HBP) with hydroxyl terminal groups is modified by the aid of saturated fatty acid groups with 7 carbon lengths. FTIR results reveal that about 85% of hydroxyl terminal groups were replaced by fatty acid chains. Having prepared and characterized the inferred modified HBP, the effect of both neat and modified forms of HBP was tested on the curing behavior of an acrylic based UV-curable inkjet ink by time-resolving photo rheo-mechanical spectroscopy (TRP-RMS). The chemo-rheological results of TRP-RMS show that the hyperbranched polymers, in both neat and modified forms affected the rheological behavior of the ink during the curing process. In this research, slope of estimated line on the chemo-rheological curves was used to measure the rate of complex viscosity growth of ink formulation during the curing process. Accordingly, slope in the blend without HBPs was 180.56Pa and it increased to about 300Pa on addition of HBPs even at a loading of as much as 2wt.%. Results demonstrate that hyperbranched polymers have altering influence at the various different stages of the curing process.