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 T_g of the complexed gel diminished with enhancement in the acrylic acid-content in the copolymer. The modulus ratio (E_g/E_r) 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, T_g, 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.