Solid state photopolymerization of acrylic acid at low temperature

Near-infrared spectroscopy was used to investigate the kinetic characteristics of acrylic acid photopolymerized at-70 degrees C and room temperature, respectively. The obtained results showed that at-70 degrees C the double bond conversion increased with increase in the initiator's concentration. Addition of soft chain component polyethylene glycol 400 (PEG400) could lead to high conversion in the solid state, and then high final double bond conversion after post-curing. The introduction of water at low temperature also contributed largely to the enhancement in the initial and final double bond conversion in solid state. SEM photographs showed that more pores came up in the cured films with the increase in the water content in the reaction system. The change in the photoinitiator concentration, amount of PEG400, and content of water had significant effect on samples cured at lower temperature than at room temperature under the same conditions. Different kinds of photoinitiators showed different contributions to the initial and final double bond conversion on photopolymerization of acrylic acid at low temperature. Significant post-curing phenomena for photopolymerization of acrylic acid at low temperature could be observed as well. Copyright (C) 2009 John Wiley & Sons, Ltd.