SynopsisShear degradation of polyisobutylene solutions was studied in laminar flow through capillaries. A special apparatus was designed with a view to a controlled shear history. The various effects of initial molecular weight, concentration, temperature, and shear stress at the wall on the final degradation product are combined in a single parameter representing the minimum force required for degrading a polymer sample to its final state.This work is based on the M.Sc. Thesis of A. Kadim, submitted a t the

In this work, antimony trioxide nanoparticles (Sb2O3NPs)-doped polyvinyl alcohol (PVA[Formula: see text]) and polyvinyl pyrrolidone (PVP[Formula: see text]) (i.e., PVAP@[Formula: see text]Sb2O3NPs, [Formula: see text], and 0.04) composite films were prepared using the casting method. Light optical microscopy (LOM), scanning electron microscopy (SEM), and Fourier infrared spectrums (FTIR) were used to investigate PVAP@[Formula: see text]Sb2O3NPs films. Sb2O3NPs were well dispersed within the matrix. FTIR showed a strong interaction between the matrix material and NPs. The density increased by up to 75% after adding 0.04[Formula: see text]wt.% of Sb2O3NPs. The mechanical ultrasound properties (MUS) were measured with different ultrasound frequencies in the ranges of (25, 30, 35, 40 and 45[Formula: see text]kHz). MUS coefficients such as ultrasonic velocity, absorption coefficient, and bulk modules were significantly improved after the impact of NPs by up to 20%, 115% and 230%, respectively. The reduction of electrical properties such as dielectric and loss constant was associated with an increase in frequency. The dielectric constant of PVAP@Sb2O3NPs was increased by about 80% after loading. AC electrical conductivity revealed an improvement with an increase in frequency and loading ratio. The results demonstrate a promising material for electromechanical, energy harvesting, and pressure sensor applications.

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