Enhanced Low-Density Silicone Foams Blown by Water–Hydroxyl Blends
Water, alcohols, diols, and glycerol are low-cost blowing agents that can be used to create the desired silicone foam structures. Although their combined use can be beneficial, it remains unclear how it affects the physical properties of the resulting materials. We conducted a comparative study of t...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-11-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/15/22/4425 |
| _version_ | 1797458005288026112 |
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| author | Ingrid Rebane Karl Jakob Levin Uno Mäeorg Urmas Johanson Peeter Piirimägi Tauri Tätte Tarmo Tamm |
| author_facet | Ingrid Rebane Karl Jakob Levin Uno Mäeorg Urmas Johanson Peeter Piirimägi Tauri Tätte Tarmo Tamm |
| author_sort | Ingrid Rebane |
| collection | DOAJ |
| description | Water, alcohols, diols, and glycerol are low-cost blowing agents that can be used to create the desired silicone foam structures. Although their combined use can be beneficial, it remains unclear how it affects the physical properties of the resulting materials. We conducted a comparative study of these hydroxyl-bearing blowing agents in fumed silica- and mica-filled polymer composite systems for simultaneous blowing and crosslinking to obtain a low-density, uniform porosity and superior mechanical properties. The foams were optimized for a uniform open-pore structure with densities ranging from 75 to 150 kg‧m<sup>−3</sup>. Varying the diol chain length (C<sub>n</sub>) from one to seven carbons can alter the foam density and structure, thereby enhancing the foam tensile strength while maintaining a low density. Replacing 10 mol% of water with 1,4-butanediol decreased the density by 26%, while increasing the specific strength by 5%. By combining glycerol and water blowing, the resulting foams exhibited a 30% lower apparent density than their water-blown analogs. The results further showed that C<sub>n</sub> > 4 alkane chain diols had an odd–even effect on the apparent density and cell wall thickness. All foamable compositions had viscosities of approximately 7000 cSt and curing times below 2 min, allowing for quick dispensing and sufficient time for the foam to cure in semi-industrial volumes. |
| first_indexed | 2024-03-09T16:30:56Z |
| format | Article |
| id | doaj.art-f6bcb06709784a2293ca03c25323a4d7 |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-09T16:30:56Z |
| publishDate | 2023-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-f6bcb06709784a2293ca03c25323a4d72023-11-24T15:02:34ZengMDPI AGPolymers2073-43602023-11-011522442510.3390/polym15224425Enhanced Low-Density Silicone Foams Blown by Water–Hydroxyl BlendsIngrid Rebane0Karl Jakob Levin1Uno Mäeorg2Urmas Johanson3Peeter Piirimägi4Tauri Tätte5Tarmo Tamm6Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, EstoniaInstitute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, EstoniaInstitute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, EstoniaInstitute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, EstoniaEstelaxe Ltd., Kivimurru 2, 65605 Võru, EstoniaInstitute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, EstoniaInstitute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, EstoniaWater, alcohols, diols, and glycerol are low-cost blowing agents that can be used to create the desired silicone foam structures. Although their combined use can be beneficial, it remains unclear how it affects the physical properties of the resulting materials. We conducted a comparative study of these hydroxyl-bearing blowing agents in fumed silica- and mica-filled polymer composite systems for simultaneous blowing and crosslinking to obtain a low-density, uniform porosity and superior mechanical properties. The foams were optimized for a uniform open-pore structure with densities ranging from 75 to 150 kg‧m<sup>−3</sup>. Varying the diol chain length (C<sub>n</sub>) from one to seven carbons can alter the foam density and structure, thereby enhancing the foam tensile strength while maintaining a low density. Replacing 10 mol% of water with 1,4-butanediol decreased the density by 26%, while increasing the specific strength by 5%. By combining glycerol and water blowing, the resulting foams exhibited a 30% lower apparent density than their water-blown analogs. The results further showed that C<sub>n</sub> > 4 alkane chain diols had an odd–even effect on the apparent density and cell wall thickness. All foamable compositions had viscosities of approximately 7000 cSt and curing times below 2 min, allowing for quick dispensing and sufficient time for the foam to cure in semi-industrial volumes.https://www.mdpi.com/2073-4360/15/22/4425open-cell cellular structureslightweight materialsblowing agentssilicone foamsporous PDMSelastomeric foams |
| spellingShingle | Ingrid Rebane Karl Jakob Levin Uno Mäeorg Urmas Johanson Peeter Piirimägi Tauri Tätte Tarmo Tamm Enhanced Low-Density Silicone Foams Blown by Water–Hydroxyl Blends Polymers open-cell cellular structures lightweight materials blowing agents silicone foams porous PDMS elastomeric foams |
| title | Enhanced Low-Density Silicone Foams Blown by Water–Hydroxyl Blends |
| title_full | Enhanced Low-Density Silicone Foams Blown by Water–Hydroxyl Blends |
| title_fullStr | Enhanced Low-Density Silicone Foams Blown by Water–Hydroxyl Blends |
| title_full_unstemmed | Enhanced Low-Density Silicone Foams Blown by Water–Hydroxyl Blends |
| title_short | Enhanced Low-Density Silicone Foams Blown by Water–Hydroxyl Blends |
| title_sort | enhanced low density silicone foams blown by water hydroxyl blends |
| topic | open-cell cellular structures lightweight materials blowing agents silicone foams porous PDMS elastomeric foams |
| url | https://www.mdpi.com/2073-4360/15/22/4425 |
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