The effects of viscoelastic properties on the cellular morphology of silicone rubber foams generated by supercritical carbon dioxide

Liao, Xia; Xu, Hao; Li, Shaojie; Zhou, Chuanjian; Li, Guangxian; Park, Chul

doi:10.1039/c5ra22242g

Cited by 54 publications

(39 citation statements)

References 41 publications

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“…The LCB-PLA foams produced by batch foaming process using CO 2 as foaming agents was described by Goel and Beckman earlier. 24 The samples with thickness of 0.4 mm were prepared by compression molding under vacuum at 180 C and then cut into the dimensions of 10 Â 10 mm 2 for foaming. The sample was then placed into a high-pressure vessel which was preheated to the experimental temperature.…”

Section: Preparation Of Lcb-pla Foams By Supercritical Comentioning

confidence: 99%

Introduction of a long-chain branching structure by ultraviolet-induced reactive extrusion to improve cell morphology and processing properties of polylactide foam

Liao

et al. 2017

RSC Adv.

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Section: Preparation Of Lcb-pla Foams By Supercritical Comentioning

confidence: 99%

Introduction of a long-chain branching structure by ultraviolet-induced reactive extrusion to improve cell morphology and processing properties of polylactide foam

Liao

et al. 2017

RSC Adv.

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“…When the precuring time of silicone rubber matrix is 10 min, the cell density reaches to the maximum value 2.96 × 10 10 cells/cm 3 . It is well known that with the extension of precuring time, the strength of silicone rubber matrix will be improved, leading to increasing of the viscosity . When the precuring time is short, the cure degree is so low that the strength of silicone rubber matrix cannot hold cell stability, which causes the cell to merge or collapse.…”

Section: Resultsmentioning

confidence: 99%

“…They first reported that the high temperature vulcanized (HTV) silicone rubber foams were prepared with scCO 2 . Liao et al investigated that the viscoelastic properties of silicone rubber play a vital role in the scCO 2 foaming process. Yang et al prepared the microcellular HTV silicone rubber foams by controlling the foaming parameters, and the smallest cell size could reached to 9.8 μm.…”

Section: Introductionmentioning

confidence: 99%

Microcellular silicone rubber foams: The influence of reinforcing agent on cellular morphology and nucleation

Xiang

Deng

Zhang

et al. 2018

Polymer Engineering & Sci

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A series of microcellular silicone rubber foams were prepared by supercritical carbon dioxide (scCO 2 ). The effect of reinforcing agent (silica) on the rheological behavior, cellular morphology and nucleation of silicone rubber composites was investigated. The results show that the silica not only acts as reinforcing agent but also plays an important role in the cellular nucleation. When the content of silica increases from 40 phr to 70 phr, the range of the calculated surface tension of silicon rubber composites/ scCO 2 (c mix ) and radius of the critical nucleus (r*) are 158.95$1,092.74 nN/m and 14.45-99.34 nm, respectively. Meanwhile, aggregated silica has good heterogeneous nucleation as the diameter of aggregated silica particles is approximate to twice r*. The smallest cell diameter and the highest cell density of the silicone rubber foam can reach to 708 nm and 1.02 3 10 11 cells/cm 3 , which indicate that the silicone rubber nanofoams can be obtained by means of the supercritical foaming technology. POLYM. ENG. SCI., 00:000-000,

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“…The primary challenge posed in foaming of rubbers stems from their elastic and soft (less rigid) structure. A limited number of studies that have appeared in the literature on foaming of silicone rubber with carbon dioxide show some of the challenges . These challenges include balancing the viscoelasticity, bubble growth and coalescence, and the need for pre‐and postfoaming curing.…”

Section: Introductionmentioning

confidence: 99%

Foaming of poly(ethylene‐co‐vinyl acetate) and poly(ethylene‐co‐vinyl acetate‐co‐carbon monoxide) and their blends with carbon dioxide

Sarver

Sumey

Williams

et al. 2017

J of Applied Polymer Sci

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Poly(ethylene‐co‐vinyl acetate) (EVA‐25) and poly(ethylene‐co‐vinyl acetate‐co‐carbon monoxide) (EVACO‐2410) and their blends with EVACO:EVA ratios of 80:20, 60:40, 40:60, and 20:80 were foamed using CO2. These foams are of interest for applications ranging from footwear to medical devices. Foaming experiments were carried out using 1 mm thick melt‐extruded films in CO2 at a range of pressures (100, 200, and 300 bar) and temperatures (30, 40, 50, and 60 °C). Foamability of the polymers was explored both under isothermal and gradient temperature conditions. Foams of EVACO‐2410 displayed high initial expansions followed by postfoaming relaxation and shrinkage while foams generated from EVA‐25 showed more dimensional stability. Blending EVACO‐2410 with EVA‐25 was explored as an approach to reduce postfoaming relaxation and shrinkage. The surfaces of the foamed samples displayed blistering that was linked to CO2 bubble entrapment and coalescence at the surface. Scanning electron micrographs of the foams generated from blends displayed distinct morphologies reflecting whether the sections were representing the machine‐ or cross‐machine direction of extruded films. In going from EVACO‐2410 to EVA‐25, the cell densities ranged from about 106 to 1010 cells/cm3. Foams with low bulk densities of about 0.11 g/cm3 could be generated. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45841.

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The effects of viscoelastic properties on the cellular morphology of silicone rubber foams generated by supercritical carbon dioxide

Abstract: Silica content, saturation temperature and pressure all have an effect on silicone rubbers' viscoelastic properties, which further has a close connection with the cellular structure.

Cited by 54 publications

References 41 publications

Introduction of a long-chain branching structure by ultraviolet-induced reactive extrusion to improve cell morphology and processing properties of polylactide foam

Introduction of a long-chain branching structure by ultraviolet-induced reactive extrusion to improve cell morphology and processing properties of polylactide foam

Microcellular silicone rubber foams: The influence of reinforcing agent on cellular morphology and nucleation

Foaming of poly(ethylene‐co‐vinyl acetate) and poly(ethylene‐co‐vinyl acetate‐co‐carbon monoxide) and their blends with carbon dioxide

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