Amidation of acrylic acid grafted polyethylene film with isopropylamine and temperature‐responsive character of the resulting amidated film

An acrylic acid (AA) grafted polyethylene (PE) film with a homogeneous distribution of grafted chains was prepared by the photografting of AA onto a low‐density PE film with a thickness of 30 μm. The AA‐grafted PE film was subjected to amidation with isopropylamine (IPA) at 25°C in water as a solvent. Up to 80 mol % of the carboxyl groups of the AA‐grafted chains could be successfully converted to N ‐isopropylacrylamide (NIPAAm) residues through the control of the amidation conditions, such as the reaction time, amount of the condensation reagent, and concentration of IPA. The resulting amidated PE film exhibited a temperature‐responsive character: the film swelled and shrank in water below and above a temperature range of about 40–60°C, respectively. The extent of the character of the amidated PE film was greater than that of NIPAAm‐ and NIPAAm/AA‐grafted PE films prepared by the photografting of NIPAAm monomer and NIPAAm/AA binary monomers, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009