Shape memory characterization of polytetra methylene oxide/poly (acrylic acid-co-acrylonitrile) complexed gel

Polymer gels of poly(acrylic acid-co-acrylonitrile) [p(AA-co-AN)] of varying compositions were synthesized and complexed with polytetramethylene oxide (PTMO) to get PTMO/p(AA-co-AN) complexed gels. The complexation occurred through H-bonding of carboxyl group of acrylic acid with ether group of PTMO. The PTMO/p(AA-co-AN) gels were characterized by DSC, DMTA and swelling ratio. Their shape memory property was evaluated by bending tests. The swelling ratio of [p(AA-co-AN)] in PTMO (as solvent) increased and Tg of the complexed gel diminished with enhancement in the acrylic acid-content in the copolymer. The modulus ratio (Eg/Er) increased with the acrylic acid content, which is conducive to better shape memory and shape recovery properties of the gels. The influence of the copolymer composition on the swelling ratio, Tg, dynamic mechanical and the shape memory properties of the complexes is examined and presented. The gels showed a shape recovery of >90%, which increased with the acrylic acid content in the copolymer.