Solid‐state microcellular high temperature vulcanized (HTV) silicone rubber foam with carbon dioxide

Yang, Qian; Yu, Haitao; Song, Lixian; Lei, Yajie; Zhang, Fengshun; Lu, Ai; Liu, Tao; Luo, Siwei

doi:10.1002/app.44807

Cited by 28 publications

(19 citation statements)

References 53 publications

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“…This large amount of cell nuclei density simultaneously growing in a restricted volume leads to a higher number (cell density) of smaller cells (average diameter) and a more uniform cell structure (narrower distribution) [ 176 ]. In another work, a series of microcellular high temperature vulcanizates (HTV) silicone rubber foams were produced using CO 2 [ 216 ]. It was shown that CO 2 diffusivity in the HTV silicone rubber also increased with saturation pressure.…”

Section: Foam Morphologymentioning

confidence: 99%

Chemistry, Processing, Properties, and Applications of Rubber Foams

Rostami‐Tapeh‐Esmaeil

Vahidifar

Esmizadeh

et al. 2021

Polymers

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With the ever-increasing development in science and technology, as well as social awareness, more requirements are imposed on the production and property of all materials, especially polymeric foams. In particular, rubber foams, compared to thermoplastic foams in general, have higher flexibility, resistance to abrasion, energy absorption capabilities, strength-to-weight ratio and tensile strength leading to their widespread use in several applications such as thermal insulation, energy absorption, pressure sensors, absorbents, etc. To control the rubber foams microstructure leading to excellent physical and mechanical properties, two types of parameters play important roles. The first category is related to formulation including the rubber (type and grade), as well as the type and content of accelerators, fillers, and foaming agents. The second category is associated to processing parameters such as the processing method (injection, extrusion, compression, etc.), as well as different conditions related to foaming (temperature, pressure and number of stage) and curing (temperature, time and precuring time). This review presents the different parameters involved and discusses their effect on the morphological, physical, and mechanical properties of rubber foams. Although several studies have been published on rubber foams, very few papers reviewed the subject and compared the results available. In this review, the most recent works on rubber foams have been collected to provide a general overview on different types of rubber foams from their preparation to their final application. Detailed information on formulation, curing and foaming chemistry, production methods, morphology, properties, and applications is presented and discussed.

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Section: Foam Morphologymentioning

confidence: 99%

Chemistry, Processing, Properties, and Applications of Rubber Foams

Rostami‐Tapeh‐Esmaeil

Vahidifar

Esmizadeh

et al. 2021

Polymers

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“…There is a strong interaction between CO 2 and silicone rubber [ 13 ], which can lead to a strong CO 2 plasticization effect. Yang et al [ 14 ] found that the CO 2 concentration of around 3% and diffusivity with a magnitude of 10 −5 cm 2 /s in high temperature vulcanized methyl vinyl silicone rubber at a CO 2 pressure of 2–5 MPa at 40 °C, and this diffusion coefficient of CO 2 in silicone rubber was 1000 times higher than that in polyetherimide. Yan et al [ 15 ] fitted the cell density with CO 2 dissolution and found that the logarithm of the cell density had a linear relationship with the square of saturation pressure.…”

Section: Introductionmentioning

confidence: 99%

Effect of Vulcanization and CO2 Plasticization on Cell Morphology of Silicone Rubber in Temperature Rise Foaming Process

et al. 2021

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Both vulcanization reaction and CO2 plasticization play key roles in the temperature rise foaming process of silicone rubber. The chosen methyl-vinyl silicone rubber system with a pre-vulcanization degree of 36% had proper crosslinked networks, which not only could ensure enough polymer matrix strength to avoid bubble rupture but also had enough dissolved CO2 content in silicone rubber for induced bubble nucleation. The CO2 diffusion and further vulcanization reaction occur simultaneously in the CO2 plasticized polymer during bubble nucleation and growth. The dissolved CO2 in the pre-vulcanized silicone rubber caused a temperature delay to start while accelerating further vulcanization reactions, but the lower viscoelasticity caused by either CO2 plasticization or fewer crosslinking networks was still the dominating factor for larger cell formation. There was a sudden increase in elastic modulus and complex viscosity for pre-vulcanized silicone rubbers at higher temperature because of the occurrence of further vulcanization, but CO2 plasticization reduced the scope of change of rheological properties, and the loss factor was close to 1 around 170 °C, which is corresponding to the optimum foaming temperature. The foamed silicone rubber had a higher cell density and smaller cell size at a higher temperature rising rate, which is due to higher CO2 supersaturation and faster vulcanization reaction. These results provide some insight into the coupling mode and effect of CO2 plasticization and vulcanization for regulating cell structure in foaming silicone rubber process.

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“…Silicone rubber (SR) has attracted great attention from industry for its extensive applications in sealants, adhesives, high voltage insulation devices, electronics, automotive, and healthcare, due to its high thermal stability, high extensibility, low dielectric constant, low surface energy, high gas permeability and excellent biocompatibility 1–6 . Unlike condensed type silicone rubber, 7,8 addition‐type silicone rubber shows low shrinkage, uniform curing, and high conversion during vulcanization, 9 besides, it holds superior operability than high temperature vulcanized silicone rubber (peroxide vulcanized silicone rubber) 10–12 . However, the weak polarity of the main chain (SiO) and lack of reactive functional groups result in poor adhesion of addition‐type silicone rubber with metal substrate 13,14…”

Section: Introductionmentioning

confidence: 99%

“…silicone rubber (peroxide vulcanized silicone rubber). [10][11][12] However, the weak polarity of the main chain ( Si O ) and lack of reactive functional groups result in poor adhesion of addition-type silicone rubber with metal substrate. 13,14 Thus, lots of studies were carried out for improving the adhesion performance of addition-type silicone rubber.…”

mentioning

confidence: 99%

Role of in‐situ polymethyl‐methacrylate in addition type silicone rubber with specific reference to adhesion and damping properties

Huang

Dai

Chen

et al. 2020

J of Applied Polymer Sci

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Herein, a strategy of embedding in‐situ polymethyl‐methacrylate (PMMA) domains in polydimethylsiloxane (PDMS) networks is proposed to enhance adhesive and damping properties of addition type silicone rubber (SR). PMMA domains improve the modulus of SR (at room temperature), which is stronger correlated to its adhesive performance, according to the Griffith criterion. Besides, the damping performance at high temperature is provided by the glass transition of thermoplastic PMMA. The PMMA/SR blends are obtained by the crosslink of PMMA and vinyl‐terminated polydimethylsiloxane (vi‐PDMS) liquid blends with polymethylhydrosiloxane, and the PMMA/vi‐PDMS liquid blends are prepared by in‐situ radical polymerization of methyl‐methacrylate (MMA) in vi‐PDMS with toluene as compatibilizer. Effects of disperse speed, compatibilizer content, and PMMA proportion on the morphologies and properties of PMMA/SR blends are studied. Small PMMA domains (around 800 nm) in PMMA/vi‐PDMS blends with narrow size distribution and well dispersion are formed at appropriate disperse speed (100–300 rpm) and abundant compatibilizer content (~100 wt% refers to vi‐PDMS). The blends with 20 wt% PMMA possess tensile strength over 8 MPa and lap shear strength over 5 MPa to stainless steel. And the blends with 50 wt% PMMA show good damping properties with tan δ over 0.15 at temperature range from −50 to 150°C. Tg‐PMMA moves slightly to lower temperature with less PMMA embedded, but Tg‐PDMS remained stable relatively.

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Solid‐state microcellular high temperature vulcanized (HTV) silicone rubber foam with carbon dioxide

Cited by 28 publications

References 53 publications

Chemistry, Processing, Properties, and Applications of Rubber Foams

Chemistry, Processing, Properties, and Applications of Rubber Foams

Effect of Vulcanization and CO2 Plasticization on Cell Morphology of Silicone Rubber in Temperature Rise Foaming Process

Role of in‐situ polymethyl‐methacrylate in addition type silicone rubber with specific reference to adhesion and damping properties

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