The objective of the study was to evaluate the relationship between the fluoride concentration of the fluoride-releasing elastomers and the acquired acid resistance of human enamel. Four kinds of fluoride concentration of the experimental fluoride-releasing elastomers were 1.25, 2.5, 3.75 and 5.0 wt%. An enamel block was cut into two smaller enamel blocks, one of which was set with an elastomer...

The present work is an in-depth study of the connections between microstructural instabilities and their macroscopic manifestations—as captured through the effective properties—in finitely strained porous elastomers. The powerful second-order homogenization (SOH) technique initially developed for random media, is used for the first time here to study the onset of failure in periodic porous elas...

The purpose of this study was to evaluate the dynamic viscoelastic properties of experimental silicone soft lining materials, Silastic MDX 4-4210 reinforced with silica fillers. Storage modulus (E'), loss modulus (E") and damping factor (tan delta) were determined using a dynamic mechanical analyzer under a deformation strain level of 0.27% at test frequency and a temperature range of 1 Hz and ...

When liquid-crystalline elastomers pass through the isotropic-nematic transition, the orientational order parameter and the elastic strain vary rapidly but smoothly, without the expected first-order discontinuity. This broadening of the phase transition is an important issue for applications of liquid-crystalline elastomers as actuators or artificial muscles. To understand this behavior, we dev...

We present a three-dimensional nonlinear finite element formulation for dielectric elastomers. The mechanical and electrical governing equations are solved monolithically using an implicit time integrator, where the governing finite element equations are given for both static and dynamic cases. By accounting for inertial terms in conjunction with the Arruda–Boyce rubber hyperelastic constitutiv...

conclusions this study indicated that the delivery rate accuracy of elastomeric infusion pumps is preserved after repeated usage. these laboratory findings suggested that elastomeric pumps could be safely refilled in the successive days to provide postoperative analgesia. results the mean flow rate in the three series of measurements showed a gradual increase; however, the difference was not st...

Polymeric nematic liquid crystals crosslinked into elastomers (solid liquid

We review in these lecture notes some of our recent work on modelling the response of nematic elastomers to applied mechanical loads and/or to electric fields, both in the static and in the dynamic regime. Our aim is to compare theoretical results based on mathematical analysis and on numerical simulations with the available experimental evidence, in order to examine critically the various rece...

The hydrophobic recovery of polydimethylsiloxane elastomers was studied after exposure to partial electrical discharge. Silicone elastomers that were thoroughly extracted of free oligomeric impurities as well as those deliberately contaminated with low molecular weight (LMW) silicone fluids were used for these studies. Contact angle and X-ray photoelectron spectroscopy revealed that the recover...

Typical bilayer wrinkle systems employ soft elastomers as the substrates. In contrast, shape memory polymers have recently emerged as attractive alternatives. Besides the shape fixing capability, shape memory polymers distinguish from elastomers in that they are rigid at room temperature, but experience significant modulus drop upon heating. We hereby report unique aspects of shape memory polym...