Acrylic acid grafting experiments

After a few minutes irradiation with a high pressure mercury lamp at about 50 C, a rather complete cover of grafted acrylic acid, acrylamide and other vinyl monomers could be obtained. In later experiments a continuous grafting method has been developed where a tape or a fiber bundle after suitable pretreatment is grafted by UV irradiation for a few seconds. Homopolymer formed is removed by washing and grafted polymer analyzed by dye absorption, IR reflection and ESCA spectroscopy. 

Figure 2 shows the effect of reaction time on percent "graft." Grafting increased initially and then leveled off before six hours. Since there is a large excess of acrylic acid available even after the longer reaction times, this leveling off is presumably due to catalyst exhaustion. A six hour reaction time was used for the remaining experiments. 

Wu, T. Gong, P. Szleifer, I. Vlcek, P. Subr V. Grenzer, J., Behavior of surface-anchored poly(acrylic acid) brushes with grafting density gradients on solid substrates 1. experiment, Macromolecules 2007, 40, 8756-8764... 

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