Solid-like and liquid-like viscoelastic behaviors at low and high temperature,
T, respectively, observed for carboxyl-terminated telechelic poly(ethyrene-butylene) (CTPEB) neutralized with octadecylamine ODA prepared by melt mixing are studied in relation with the structure examined by XRD, FT-IR, DSC and small angle neutron scattering. When the mole ratio of -NH
2 and -COOH, NH
2/COOH in CTPEB/ODA is 1.4 or higher, CTPEB/ODA was solid-like at 298K, while it was liquid-like having almost the same viscosity as CTPEB at 343K. The network structure formed at low
T was easily fractured by small strain and cannot be reformed at low
T. However, when the sample is annealed at 353K, cooled and kept for a few hours at
T < 300K, the solid-like behavior is reproduced. It was concluded that the network formation at low
T and its disappearance at high
T for CTPEB/ODA is caused by non-crystalline association/dissociation of C18 residues in ODA connected to CTPEB by ionic bond (NH
3+COO
-). Due to the small
Mw of CTPEB, only longer chains (∼ 1/3 of total chains) connected to ODA aggregates form network structure and sustain the constant
G'in this system at low
T.
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