In the present work poly (N-vinyl-2-pyrrolidone-co-methyl methacrylate) copolymers were prepared successfully and cleanly by a one step process via cationic copolymerization of N-vinyl-2-pyrrolidone (NVP) with methyl methacrylate (MMA), in heterogeneous phase using "Maghnite-H+" (Mag-H+) as catalyst in bulk, Maghnite is a montmorillonite sheet silicate clay exchanged with protons to produce Maghnite-H+. Temperature is varied between 20 and 80 °C. The effects of reaction temperature, amount of Mag-H+ on the yield and the intrinsic viscosity (η) were investigated. A typical reaction product of poly (NVP-coMMA) was analyzed by infra red spectroscopy (FTIR) and 1 H-NMR, 13 C-NMR spectroscopy as well as by viscosimetry.

Telechelic poly (propylene oxide) (PPO) bismacromonomers bearing methyl Acetate end groups, were prepared by cationic ring-opening polymerization of propylene oxide (PO), in the presence of Acetic anhydride, catalyzed by Maghnite-H + (Mag-H + ), in bulk. Mag-H + is a montmorillonite sheet silicate clay which was exchanged with protons.The influence of the amount of acetic anhydride and the reaction time on The polymerisation yield and molecular weight were studied. The products have been caracterized by Nuclear magnetic resonance ( 1 H-NMR).

Purpose This paper aims to propose a new hydrostatic squeeze film damper compensated with electrorheological valve restrictors to control the nonlinear dynamic behavior of a rigid rotor caused by high unbalance eccentricity ratio. To investigate the effect of electrorheological valve restrictors on the dynamic behavior of a rigid rotor, a nonlinear model is developed and presented. Design/methodology/approach The nonlinear results are compared with those obtained from a linear approach. The results show good agreement between the linear and nonlinear methods when the unbalanced force is small. The effects of unbalance eccentricity ratio and electric field on the vibration response and the bearing transmitted force are investigated using the nonlinear models. Findings The results of simulation performed that the harmonics generated by high unbalance eccentricities can be reduced by using hydrostatic squeeze film damper compensated with electrorheological valve restrictors. Originality/value The numerical results demonstrate that this type of smart hydrostatic squeeze film damper provides to hydrostatic designers a new bearing configuration suitable to control rotor vibrations and bearing transmitted forces, especially for high speed.