Cellular structure design by controlling the dissolution and diffusion behavior of gases in silicon rubber

Synergistic Effects of Multiple Environmental Factors on Degradation of Silicone Rubber Seals under Marine Atmosphere

“…Firstly, water and additives in silicone rubber specimens can escape in large quantities, which can lead to a reduction in specimen weight. According to the references [32][33][34][35], high temperature promotes the escape process, while oil and compression stress inhibit it. Secondly, small molecules of oxygen and oil can enter the silicone rubber matrix by diffusion, leading to a rise in weight.…”

A facile and efficient strategy for fabrication of silicone rubber foam based on in situ precuring‐supercritical CO2 foaming technology

“…It is believed that a lower foaming temperature tends to produce a smaller cell size and larger cell density because the solubility of CO 2 in polymer is higher at lower temperature, leading to generation of more cell nucleation sites. 25,35 Moreover, melt viscosity and melt strength of polymer are high enough at lower temperature, leading to a sufficient retractive force to restrict cell expansion. With an increase in temperature, the solubility of CO 2 in polymer decreases, resulting in a reduction of supersaturation degree and limited generation of cell nucleation sites.…”

Supercritical CO2Foaming of Lightweight Polyolefin Elastomer/trans-Polyoctylene Rubber Composite Foams with Extra-Soft and Anti-Shrinkage Performance

“…Among current foaming processes, supercritical carbon dioxide (scCO 2 ) foaming is considered as an ideal method to fabricate high-performance polymer foams owing to its environmentally friendly performance and high structural controllability. − However, the preparation of POE using scCO 2 foaming has faced serious shrinkage and narrow foaming window problems because of the strong movement ability of chain segments and poor melt strength of the elastomer. , For example, Zhao et al found that the POE foams with a higher octene content have more serious shrinkage problems due to the lower compression modulus, weaker crystal structure, and higher CO 2 permeability . In general, the shrinkage behavior is very common in the elastomer foams prepared via CO 2 foaming.…”

“…However, the permeability of CO 2 in the polymer is much higher than that of air, which will create a negative pressure between the foam and air. Different from the plastic foam, the elastomer foam has a low modulus at room temperature and cannot resist the compressive force induced by negative pressure, resulting in the volume shrinkage. , Moreover, the shrinkage and foaming behavior of polymer foam are determined by the intrinsic properties of the polymer matrix, cell morphology, and different kinds of blowing agents. For example, Wang et al proposed a novel strategy of implementing mixed CO 2 and N 2 as blowing agents in microcellular foaming to stabilize the cell structure and modulate the shrinkage behavior of TPE foams .…”

“…17−19 However, the preparation of POE using scCO 2 foaming has faced serious shrinkage and narrow foaming window problems because of the strong movement ability of chain segments and poor melt strength of the elastomer. 4,18 For example, Zhao et al found that the POE foams with a higher octene content have more serious shrinkage problems due to the lower compression modulus, weaker crystal structure, and higher CO 2 permeability. 20 In general, the shrinkage behavior is very common in the elastomer foams prepared via CO 2 foaming.…”