Semi-interpenetrating polymer networks based on polyurethane and poly(2-hydroxyethyl methacrylate): Dielectric study of relaxation behavior

Lyudmyla Karabanova (1) , Gisèle Boiteux (2) , Gérard Seytre (2) , Isabelle Stevenson (2) , O. Gain (2) , Chady Hakme (2) , Elena D. Lutsyk (1) , Anna V. Svyatyna (1)

1 Institute of Macromolecular Chemistry of National Academy of Sciences of Ukraine
2 IMP-LMPB - Ingénierie des Matériaux Polymères - Laboratoire des Matériaux Polymères et des Biomatériaux

The study of molecular dynamics by broadband dielectric spectroscopy (BDS) is presented for polyurethane (PU), poly(2-hydroxyethyl methacrylate) (PHEMA) and for semi-IPNs based on PU and PHEMA synthesized by photopolymerization. The dielectric properties were performed in wide range of frequencies and temperatures with the goal to establish the relation between the relaxations and the structure. Five relaxation phenomena were finally detected for PHEMA : gamma-, beta sw-, beta-relaxations at low temperatures and a-relaxation at 150 degrees C at high frequencies plus ionic conductivity relaxation which starts at 0 degrees C. For semi-IPNs the overlapping of gamma- and beta sw-relaxations of PHEMA (-125/-75 degrees C) then with increasing the temperature alpha-relaxation in PU (-75/0 degrees C), next ionic conductivity relaxation which starts at 0 degrees C, and finally the alpha-relaxation of PHEMA (+125/+170 degrees C) were detected. The alpha-relaxation of PHEMA in semi-IPNs shifts to lower temperatures and became broader with increasing amount of PU due to incomplete phase separation in the system and formation of interphases. The dielectric relaxation phenomena were fitted with Havriliak-Negami equation. Activation energy, tau(o) and alpha parameters were calculated. For alpha-relaxations corresponding dielectric characteristics have been determined from Vogel-Fulcher-Tammann equation. The relaxation map for investigated PU, PHEMA and semi-IPNs was built.

Mots clés: Biomaterials; Electrical and electronic properties; Dielectric properties; relaxation; electric; modulus; Mechanical properties; Mechanical; stress relaxation; Polymers and organics; Viscoelasticity

Domaines: Polymères

Lyudmyla Karabanova, Gisèle Boiteux, Gérard Seytre, Isabelle Stevenson, O. Gain, et al.. Semi-interpenetrating polymer networks based on polyurethane and poly(2-hydroxyethyl methacrylate): Dielectric study of relaxation behavior. Journal of Non-Crystalline Solids, 2009, 355, pp.1453-1460. ⟨10.1016/j.jnoncrysol.2009.05.002⟩. ⟨hal-00423360⟩