| Abstract: | The effects of a mixed solvent consisting of water and organic solvents such as acetone and methanol on the photografting (λ > 300 nm) of N‐isopropylacrylamide (NIPAAm) on linear low‐density polyethylene film (thickness = 30 μm) was investigated at 30°C and 60°C. Xanthone, which had been coated on the film, was used as a photoinitiator. The photografting initiated even in the system at 30°C by using a longer irradiation time. It was found that the maximum percentage of grafting was attained at a certain concentration of organic solvent in the mixed solvent, which shifted to a lower concentration of organic solvent in the system at 60°C compared with the system at 30°C. It was found that the grafted chains of the sample prepared in the system with the higher polymerization temperature and the use of mixed solvent penetrated into the center of the film compared with the sample prepared in the system with the lower polymerization temperature and use of a water solvent. Moreover, the NIPAAm‐grafted films exhibited temperature responsiveness, swelling and shrinking in water at 0°C and 50°C, respectively. The extent of this characteristic was found to be closely related to the location of the grafted chains in film substrate, which was measured by an attenuated total reflection infrared spectroscope and a scanning electron microscope. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 458–463, 2003 |
